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Oh man oh man, this could be good. Fingers crossed. @$1199 it's excellent per channel cost, got input And output xformers, and also an an output knob per channel, which could be useful when not only for good gain staging, but especially if these trannys overdrive pleasantly. Plus the op amps are easily swappable. If I'm dreaming I don't wanna wake up! I hope it sounds as cool as it seems on paper!

Comments

kmetal Thu, 10/06/2016 - 21:07

Looks like API updated the 512c 500 series pre to the 500v, and included an output attenuation knob. This is great. Having used the 512c once on bass at the studio, which was enough to make me want it, this new version really really makes me want it.

This is an exciting time for gear, and I think designers are finally past the first hump of digital about 40 years into its integration in audio. Analog took about 80-85 years to get refined.

This is an exciting time for both ITB and analog since things are moving passed the problem solving or comprise points, into good sonics and creativity again.

From thins like melodynes audio to midi functionality to Sibelius turning print music into midi, tabulators, and even sound thru vsti, many of the things I 'wished' I could do just a few years back are now super easy, and possible.

I think we've entered a new era. Latency is dropping, native computer power is competitive, the fizzy stuff of pre 2013 records is gone (mostly at least) I think due to better clocking/conversion, and 64bit OS, this is a wonderful time to be a creative professional. I happened to be in the market for new stuff for the first time in 6-8 years, but I think anyone could with a 'rack review' of there own and perhaps swap out some of there audio door stops for some of these new toys at no pain to the pocket.

audiokid Thu, 10/06/2016 - 21:30

kmetal, post: 441950, member: 37533 wrote: I think we've entered a new era. Latency is dropping, native computer power is competitive, the fizzy stuff of pre 2013 records is gone (mostly at least) I think due to better clocking/conversion, and 64bit OS, this is a wonderful time to be a creative professional.

I agree.

DonnyThompson Fri, 10/07/2016 - 07:23

The only thing about Warm Audio that I've noticed over the years, ( and I could be wrong but I don't think I am) is that they seem to use Cinemag XFO's pretty much exclusively in everything they make that uses XFO's.
I don't hate Cinemag trannies, but when I was doing the ADK Mic Pre for vocals shoot-out here on RO a few years back, and then posting blind listening tests, the Cinemag was always more towards the bottom of the rankings of sonic preference with those that listened and commented.
( FWIW The consistently top-rated was the Lundhal 1538, which is also used in Focusrite's ISA series, and is also a common replacement XFO for Ribbon Mic mods...)

Of course there are variables... and there's no doubt that Cinemag makes more than just one input/output XFO. I'd be very interested to hear what you think once you put it through its paces, K. :)

kmetal, post: 441950, member: 37533 wrote: Looks like API updated the 512c 500 series pre to the 500v, and included an output attenuation knob. This is great. Having used the 512c once on bass at the studio, which was enough to make me want it, this new version really really makes me want it.

There are some who adore the sound of API, others who find it preferable for only certain things, and still others who don't really care for it at all. I happen to be in the middle camp, I think API is great for snare, toms, electric guitar amps and DI'd basses... but it's not traditionally been my first choice for vocals, or other tracks that have more "nuance". Jensen and Lundhal seem to be my main go-to's for those things. But, that's a personal preference thing, not an unequivocal statement across the board.

The bottom line is, if you like the way it sounds, be it Cinemag or API, then absolutely nothing else matters. ;)

kmetal, post: 441950, member: 37533 wrote: This is an exciting time for both ITB and analog since things are moving passed the problem solving or comprise points, into good sonics and creativity again.

I absolutely agree. There are RO members who prefer analog, those who prefer digital, those who prefer a hybrid workflow. Some of us like plug-in's, some of us not as much, some not at all.
Here's the thing for me, and the way I look at it... that technology has given us a plethora of choices in which we can create and work in whatever way we want.. and that's what I find to be most attractive.
There's some new digital technology that I love, and some I don't... there's some analog technology that I love, and some things I don't. I'm not scared or wary of new things just because they are new, nor am I enslaved by "old" ways, either. If new technology wasn't embraced through the years, then we'd still be recording to cylinders and wire ... sometimes new is great, sometimes not, sometimes old is awesome, sometimes not.
In any case, technology has given us the choice(s) to work in whatever way we find to be the most productive to our personal creativity... And that's important to me. ;)

IMHO of course.
-d.

audiokid Fri, 10/07/2016 - 11:34

DonnyThompson, post: 441960, member: 46114 wrote: I don't hate Cinemag trannies, but when I was doing the ADK Mic Pre for vocals shoot-out here on RO a few years back, and then posting blind listening tests, the Cinemag was always more towards the bottom of the rankings of sonic preference with those that listened and commented.

+1
Interesting, some gear I've sold, didn't like too much had Cinemag.

DonnyThompson Fri, 10/07/2016 - 18:56

audiokid, post: 441978, member: 1 wrote: What makes one tranny different from another?

There are several variables- the number of winding's, the winding ratio, voltage rating, etc.
I'm no XFO expert, so someone like Bos ( Boswell) - or even John Hardy himself if he is lurking - would be able to explain more about what factors determine the differences.
XFO's aren't all that different from tube stuff, really... in that certain tubes have certain characteristics - both good and bad - and while I've never heard a "bad" XFO, I've certainly heard those that I prefer more than others.
Some times the differences are esoteric, and it takes a trained ear to hear them... while other times, the differences are pretty much in-your-face obvious.

But, it also depends on the mic, the singer...

In my own experience, having a choice between Jensen, Lundhal, Sowter, ADK and Cinemag input XFO's, I tend to go with he Jensen and the Lundhal, and probably out of those two, I use the Lundhal most.
Out of the output XFO's I have - (John Hardy, Seventh Circle, ADK and the ADK Neve-Style) - my favorite one to use, with both the Lundhal and the Jensen, is constantly the JH 990 discreet op amp.
I really like this combo for vocals ( at least my own and two of my biggest clients). The 990 has a very smooth mid-range presence to it, but is still present, and up front, but not at all harsh. The low end is nice and tight, not muddy or "frumpy".
The Seventh Circle OA has a very SSL type vibe to it, a "fast" sound, high detail and clarity, and when pushed, it can develop a very pleasing "edge" in the top-top end.
The ADK Neve Clone is indeed very Neve-ish... it has that "classic" warm, rich sound, silky high's. The mid-range is a bit more subdued, but a great edge when pushed.

All of these were tested using my voice on an AKG 414EB/C12 mic, in a treated room. I did similar tests with a few clients, both experienced studio singers... one male, one female. The Jensen was #1 for the female vocal, with the Lundhal ranking a close 2nd.
The Lundhal fared best for male vocals, with the Jensen coming in a close 2nd. In both cases, the JH 990 discreet Op-Amp was the best-sounding choice for those singers, using that mic, and in the same environment.

I experimented with some re-amping as well; sending vocals out to the ADK that had been previously recorded through a Presonus 1818; and out of all the choices, the Sowter input and Seventh Circle OpAmp combo sounded best for that particular workflow... although I have no explanation as to why. I'm more than happy to entertain theories. ;)

d.

kmetal Fri, 10/07/2016 - 20:52

DonnyThompson, post: 441960, member: 46114 wrote: Of course there are variables... and there's no doubt that Cinemag makes more than just one input/output XFO. I'd be very interested to hear what you think once you put it through its paces, K

Could be a while man... But I'll be sure to report. According to the video the warm used "altran USA" trannies.

DonnyThompson, post: 441960, member: 46114 wrote: I think API is great for snare, toms, electric guitar amps and DI'd basses...

I've only used it for bass DI that one time. It made the same bass I usually used sound instantly more 'like I record' so that's really the only reason I want a 512. I'm so critiacAl and negative that when something sounds actually good to me right away, it's usually a keeper. Although I do take a second listen just in case.

After using the calrec, it's my opinion that calrec/neve smokes API in general. I feel like neve does anything API could do, and the things it can't. That said, for bass di i think I still err towards the 512.

I tend to like the lundyl in the ISA stuff, and whatever is in those calrecs in general as far as xfo sound. On more than one occasion I've noticed something sounding exceptional and it was the ISA (to my surprise) and the carelec/neve stuff.

That said I belive van halen used API after the first record which was a UA 610 (original)

I don't thin swapping xfo is very hard for a tech. I know one of the kids at the studio had a Jensen swapped into his eureka for like $100.

When I think Jensen I think big full and dark (slightly) lundyl I think smooth and full. Cinemag I'm not reall familiar w the tendencies.

I don't know a whole lot about xfo besides I tend to like their sound in pre amps. Even an old Tascam mixer was noticeably good and had xfo in the path.

Xfo does to mic pre amps, what tubes do to guitar amps imho.

Tubes in mic pres don't have to necessarily be dark or saturated, they can be very clear like a Manley, but they seem to err to vintage to my ears.

Before I used tube and tranny pres I was obsessed w getting a tube pre but really it's the tranny sound I tend to lean towards. It's thick and 'modern' even tho I hate modern as a sound description, as well as 'like a record' lol it's cliche night for me.

DonnyThompson Sat, 10/08/2016 - 07:14

kmetal, post: 441986, member: 37533 wrote: Before I used tube and tranny pres I was obsessed w getting a tube pre but really it's the tranny sound I tend to lean towards. It's thick and 'modern' even tho I hate modern as a sound description, as well as 'like a record' lol it's cliche night for me.

And yet, there are those who prefer neither tubes or trannies... opting for the clearest and cleanest path to the destination as possible. Chris ( audiokid ) tends to prefer this route - I'm not inferring that he hates tubes or trannies, but he tends to lean more towards a transformer-less signal path, opting for as much transparency and lack of "character' as possible (although I suppose that the argument could be made that this "lack of character' found in these designs could be considered to offer a "vibe" of their own, LOL, if you consider ultra-clean to be a "character" description of its own). ;)

While there is nothing that is truly 100% transparent, there are pre's that offer far less color, character, and vibe than tube and/or trannie designs.
Grace and Millennia are a few preamp manufacturers that offer a discreet transformer-less signal path, and are known for being far more "transparent" than pre's that are tube or trannie.
Interestingly enough though, it does seem to be - at least as of this writing - that there are far more tube/trannie pre's available out there than there are transformer-less.

I think that most here on RO know me well enough to know that I'm not hell-bent in any one direction. I like options, I like choices, I embrace technological advances in our craft that allows this range of choices.
In my perfect world of preamps, I'd like to have a plethora of all styles: a few tube pre's, a few XFO designs, FET, Transformer-less, even hybrids like the Studio Projects VTB1 is a cool little amp; which offers both tube and solid state, and lets you select either/or, or even blend between them in varying degrees.

Mics enter into the equation as well... I like mics with XFO's - and those without. I like mics with tubes, and those without. Having a nice, wide, sonic pallet to choose from, letting you select which is best, based on the context of the song; and for the individual vocalist as well, is highly advantageous.
Technology is a very good thing. It gives us choices, which are also a very good thing.

Sonically speaking, it'd be a pretty boring world if we were all using the exact same gear, wouldn't it? It'd be a lot like restricting artists to painting with only the exact same shades of red, blue, and green... ;)

IMHO :)
-d.

kmetal Sat, 10/08/2016 - 14:01

I agree completely D. I also like to have options. I think 'clean/transparent' gets a bad rap becuase of the rarely reputation of solid state gear and digital. And cheap clean/transparent is often flat and clinical.

When you get into things like grace and millennia what they do by being clean is unlock space and dimension. IMHO.

I look forward to having a nice unr from millennia or grace. I'll likely go ISA then something super clean. Then neve or API, then a tube unit. Over the next 5 years.

One thing I will say is that I very much like the tla 100 compresser, and the retro 176, has a great reputation. People love the la2a, so if I get an OB compressor/pair I'm probably gonna shoot for tube based.

The tla 100 is way to expensive for me, and it only does one thing, but that dull silk it does so works amazingly w bright voices mics and pres and it just does a nice job of it.

audiokid Sat, 10/08/2016 - 14:33

DonnyThompson, post: 441990, member: 46114 wrote: And yet, there are those who prefer neither tubes or trannies... opting for the clearest and cleanest path to the destination as possible. Chris ( audiokid ) tends to prefer this route - I'm not inferring that he hates tubes or trannies, but he tends to lean more towards a transformer-less signal path, opting for as much transparency and lack of "character' as possible (although I suppose that the argument could be made that this "lack of character' found in these designs could be considered to offer a "vibe" of their own, LOL, if you consider ultra-clean to be a "character" description of its own).

Not exactly, let me explain my approach a bit clearer:

I love character and sometimes the dirtiest patch as possible. Just not when it comes to a summing or mastering console, that is, unless I want to insert the character at will rather than it always forced in a mix or a track.

My favourite pre of all time is the Millennia M-2b which has a tube in it. And I also love the ADL 600 which is far from clean.

On the other side of the fence, I like Lavry SS preamps because they sound very natural making a choice pre for mobile acoustic work like choirs, acoustic instruments where transparent accuracy is likely more important.
One of my all time vocal chains is the M-2b > UA LA2A/1176 l combo followed by a Pultec MEQ-5 which has a big ass tranny. That's a lot of character.

Its not that I don't like trannies and tubes, it's that I don't want them on the console when I have a choice system like what I built. Especially when I have modular options to get character in a more refined "modular" fluid workflow (ITB or OTB).

Being said... If I had to choose a console, no choice of ever getting a modular chain like what I describe, I would likely look to API or Neve and forget I ever discovered the transformerless console combined with outboard pre's etc.

kmetal Sun, 10/09/2016 - 20:44

I think the question is, is the warm audio missing something vs the API, or is the API just rendered overpriced now.... I hope someone here on RO tries the warm version. Lord knows the mags are likely gonna rave about it, while simultaneously publishing adds. Lol although tape op and SOS are Somewhat honest. If you know how to interpret their language lol.

JWHardy Thu, 10/13/2016 - 17:33

DonnyThompson, post: 441980, member: 46114 wrote: There are several variables- the number of winding's, the winding ratio, voltage rating, etc.
I'm no XFO expert, so someone like Bos ( Boswell) - or even John Hardy himself if he is lurking - would be able to explain more about what factors determine the differences.

I have not read the entire thread in detail, but here are a few comments:

I try to emphasize the importance of the "impedance ratio", or "turns ratio", or "step-up ratio" (they are all saying the same thing in different ways), and the importance of using the transformer with the lowest ratio if you want the lowest distortion and widest bandwidth. If you want color and flavor, the higher ratio models will be more appropriate.

Check the Jensen Transformers page for selecting mic input transformers:

http://www.jensen-transformers.com/transformers/mic-input/

The older version of this page (pre-Radial) included the "-3dB" bandwidth of each model. Here are those specs for their main mic input models:

JT-16-A/B: 220 kHz (1:2 ratio)
JT-13K7-A: 120 kHz (1:5 ratio)
JT-110K-HPC: 100 kHz (1:8 ratio)
JT-115K-E: 90 kHz (1:10 ratio)

You can see that the lower the step-up ratio, the wider the bandwidth. Basic laws of physics at work. Each of the Jensen models is the best that it can be for its particular step-up ratio. The step-up ratio is chosen based on the characteristics of the op-amp or tube that follows the input transformer. The 990 discrete op-amp has the lowest noise when driven by a low source impedance, so the JT-16-A/B is the ideal match for it. Quoting from the JT-16-A data sheet:

"This transformer, with its 750 Ω secondary source impedance, will produce the best signal-to-noise performance with ultra-low e(subscript "n") amplifiers such as the Jensen JT-990-C module."

So Deane Jensen came up with the ideal combination of input transformer and op-amp, the JT-16 and 990. In the earlier days, it was a "JE" number, not "JT", but that's another story. Many other op-amps and vacuum tubes are quietest when dealing with higher source impedances, so that is where the higher-ratio transformers come in.

On the plus side, the higher ratio transformers provide more voltage gain than the lower ratio transformers. The JT-16 with its 1:2 ratio provides 5.7 dB voltage gain, while the JT-115K-E with its 1:10 ratio provides 19.75 dB of voltage gain. So you have a trade-off of voltage gain vs. distortion and bandwidth. Inescapable laws of physics and the trade-offs involved. You need more turns of wire on the secondary winding for the higher ratio transformers, and this creates higher inductance and reduced bandwidth, etc.

Since the JT-16 provides only 5.7 dB of voltage gain, Deane no doubt though that it would be a good idea to add a 2nd 990 op-amp in series with the first 990 so that very high gain situations would split the gain between two 990s rather than push one 990 to provide all the gain. If you need 60 dB of gain, 5.7 dB comes from the JT-16, the remaining 54.3 dB must be provided by one 990, or 27.15 dB from each of two 990s. This is what the Jensen Twin Servo does.

Then there are issues of how accurately the windings of a transformer are made. Also, how they are configured - one winding, or multiple windings, interleaved windings, and so on. What about core material? 80% nickel, 50% nickel, 97% iron, other materials. Size of the bobbin, therefore the size of the windings, maximum signal level the windings and core material can handle... So may ways to cause changes.

I have always relied on Jensen because, in my strong opinion, they make the world's best audio transformers. If you prefer something else, I respect that. Whatever makes you happy. But if you want the widest bandwidth and lowest distortion, etc., The JT-16 is the best there is, followed by the 990, followed by the Jensen JT-11-BMQ output transformer with its 1:1 ratio, astonishingly low distortion and bandwidth of 15 MHz. It is not listed on the Jensen site, but it is essentially the same as the JT-11-BMCF, which is listed.

And so on.

John Hardy
The John Hardy Co.
www.johnhardyco.com

audiokid Thu, 10/13/2016 - 18:34

JWHardy, post: 442181, member: 19368 wrote: I have not read the entire thread in detail, but here are a few comments:

I try to emphasize the importance of the "impedance ratio", or "turns ratio", or "step-up ratio" (they are all saying the same thing in different ways), and the importance of using the transformer with the lowest ratio if you want the lowest distortion and widest bandwidth. If you want color and flavor, the higher ratio models will be more appropriate.

Check the Jensen Transformers page for selecting mic input transformers:

http://www.jensen-transformers.com/transformers/mic-input/

The older version of this page (pre-Radial) included the "-3dB" bandwidth of each model. Here are those specs for their main mic input models:

JT-16-A/B: 220 kHz (1:2 ratio)
JT-13K7-A: 120 kHz (1:5 ratio)
JT-110K-HPC: 100 kHz (1:8 ratio)
JT-115K-E: 90 kHz (1:10 ratio)

You can see that the lower the step-up ratio, the wider the bandwidth. Basic laws of physics at work. Each of the Jensen models is the best that it can be for its particular step-up ratio. The step-up ratio is chosen based on the characteristics of the op-amp or tube that follows the input transformer. The 990 discrete op-amp has the lowest noise when driven by a low source impedance, so the JT-16-A/B is the ideal match for it. Quoting from the JT-16-A data sheet:

"This transformer, with its 750 Ω secondary source impedance, will produce the best signal-to-noise performance with ultra-low e(subscript "n") amplifiers such as the Jensen JT-990-C module."

So Deane Jensen came up with the ideal combination of input transformer and op-amp, the JT-16 and 990. In the earlier days, it was a "JE" number, not "JT", but that's another story. Many other op-amps and vacuum tubes are quietest when dealing with higher source impedances, so that is where the higher-ratio transformers come in.

On the plus side, the higher ratio transformers provide more voltage gain than the lower ratio transformers. The JT-16 with its 1:2 ratio provides 5.7 dB voltage gain, while the JT-115K-E with its 1:10 ratio provides 19.75 dB of voltage gain. So you have a trade-off of voltage gain vs. distortion and bandwidth. Inescapable laws of physics and the trade-offs involved. You need more turns of wire on the secondary winding for the higher ratio transformers, and this creates higher inductance and reduced bandwidth, etc.

Since the JT-16 provides only 5.7 dB of voltage gain, Deane no doubt though that it would be a good idea to add a 2nd 990 op-amp in series with the first 990 so that very high gain situations would split the gain between two 990s rather than push one 990 to provide all the gain. If you need 60 dB of gain, 5.7 dB comes from the JT-16, the remaining 54.3 dB must be provided by one 990, or 27.15 dB from each of two 990s. This is what the Jensen Twin Servo does.

Then there are issues of how accurately the windings of a transformer are made. Also, how they are configured - one winding, or multiple windings, interleaved windings, and so on. What about core material? 80% nickel, 50% nickel, 97% iron, other materials. Size of the bobbin, therefore the size of the windings, maximum signal level the windings and core material can handle... So may ways to cause changes.

I have always relied on Jensen because, in my strong opinion, they make the world's best audio transformers. If you prefer something else, I respect that. Whatever makes you happy. But if you want the widest bandwidth and lowest distortion, etc., The JT-16 is the best there is, followed by the 990, followed by the Jensen JT-11-BMQ output transformer with its 1:1 ratio, astonishingly low distortion and bandwidth of 15 MHz. It is not listed on the Jensen site, but it is essentially the same as the JT-11-BMCF, which is listed.

And so on.

John Hardy
The John Hardy Co.
www.johnhardyco.com

John, what an honor seeing you here and thank you for taking the time to write all that. :love:

DonnyThompson Fri, 10/14/2016 - 08:23

JWHardy, post: 442181, member: 19368 wrote: I have not read the entire thread in detail, but here are a few comments:

Holy crap! What an awesome post, John!!! It's like Moses coming down from the mountain with the tablets... LOL...(y)

Man, I'm gonna save this to my files right NOW... as a fan of transformers in mic preamps, this stuff is pure gold to me. I don't pretend to understand everything ( or even much) about transformers, but posts like yours really help me to learn more about a subject that I'm really interested in. I wasn't expecting you to take the time to explain all this, John, but I'm sure glad you did - thank you very much for stopping by RO and helping me to understand this subject a little better. :)

If you happen to stop by RO again ( I really appreciate you giving the info you have thus far, and understand if you can't get back here); I have a few questions...that may be considered to be of the most elementary type...please forgive my ignorance, I'm trying to keep up, and wrap my brain around all of this...

JWHardy, post: 442181, member: 19368 wrote: Since the JT-16 provides only 5.7 dB of voltage gain, Deane no doubt though that it would be a good idea to add a 2nd 990 op-amp in series with the first 990 so that very high gain situations would split the gain between two 990s rather than push one 990 to provide all the gain. If you need 60 dB of gain, 5.7 dB comes from the JT-16, the remaining 54.3 dB must be provided by one 990, or 27.15 dB from each of two 990s. This is what the Jensen Twin Servo does.

Using the above example you have given, (referring to the factor of 60db for example purposes), can you clarify the advantages/disadvantages to using one 990 with the JT16, and having the single 990 providing all of the remaining 54.3 db of gain needed, as opposed to using two JH990's, and obtaining the remaining gain from both? (ie. less distortion? cleaner overall sound? not as much "sonic" character?, easier to build? or... none of the aforementioned?)
Or... are you saying that the Jensen Twin Servo alleviates the need for a second JH990?

As of right now, I'm using an ADK AP1 mic pre, and one of the transformers I have in my collection is a Jensen JT110k. (The others I have to to choose from are a Sowter 9040R(?), an ADK "stock", a Cinemag, and a Lundhal 1538XL).
I realize that the turn ratio is higher in the JT110K ( is it 1:8?) than it is in the JT16 1:2, but all the same, I really do like the sound that the JT110K transformer presents when used in combination with your JH 990... I also really like the sound of the Lundhal 1538 when used with the 990 ( at least for my vocal through an AKG 414EB/CK12,) but now, after reading your post, I'm gonna have to do some research and find out if the the JT16A/B is available in the 7-pin, removable, "pop and swap" format for the ADK AP1 mic preamp I have...
(FWIW, The other (output) XFO's I have - besides the JH990 - includes a Seventh Circle, an ADK "Vintage N", and an unmarked model that I'm assuming is the "stock" ADK Crimson).

Thanks so much again, John :)

-donny

JWHardy Fri, 10/14/2016 - 09:28

Donny;

DonnyThompson, post: 442215, member: 46114 wrote: Using the above example you have given, (referring to the factor of 60db for example purposes), can you clarify the advantages/disadvantages to using one 990 with the JT16, and having the single 990 providing all of the remaining 54.3 db of gain needed, as opposed to using two JH990's, and obtaining the remaining gain from both? (ie. less distortion? cleaner overall sound? not as much "sonic" character?, easier to build? or... none of the aforementioned?)
Or... are you saying that the Jensen Twin Servo alleviates the need for a second JH990?

My M-1 mic preamp uses the JT-16-B and one 990 op-amp. The Jensen Twin Servo uses the JT-16-B and two 990 op-amps connected in series. Here is the gain situation in the "60 dB gain scenario":

M-1: 5.7 + 54.3 = 60
Jensen Twin Servo: 5.7 + 27.15 + 27.15 = 60

Consider a 3rd variation of the "60 dB gain scenario" where you have a high-ratio transformer such as the JT-115K-E that provides about 20 dB of voltage gain. The vacuum tube or op-amp or op-amps that immediately follow the JT-115K-E must provide 40 dB of gain to get you to the desired total of 60 dB. 20 + 40 = 60

The high-ratio JT-115K-E (and the JT-110K-HPC) have the advantage of providing lots of voltage gain (about 20 dB for the JT-115K-E, about 18 dB for the JT-110K-HPC), so the op-amp following them does not have to provide as much gain to get you to 60. Therefore, the op-amp operating at 40 dB of gain will not be pushed to such a high gain that distortion starts to rise.

Both the M-1 and Jensen Twin Servo will do a great job at 60 dB of gain. I don't have specific distortion and bandwidth specs to give you, but the Twin Servo will have a slight edge. Sometimes I put it this way: on a scale of zero to ten, both of these preamps are in the nineties. The character of both preamps should be very similar because they use the same input transformer, same op-amp, same output transformer, there are no coupling capacitors in the signal path. Same basic power supply (some grounding differences), same meter card, same basic frame. So the sonic differences should be slight, and they will be at high gain settings because of the single-stage vs. two-stage design. But I will leave that up to the users that have tried both to describe in terms of sonic character, etc.

There are twice as many 990 op-amps in the Twin Servo, so there is a lot more circuitry to assemble (and to squeeze into the existing space of the original M-1 card format). More adjustments to make (the "input bias current compensation" adjustments and the "DC servo" adjustments). The input bias current compensation circuitry is more complex on the Twin Servo, and it is NOT the circuit that is shown in the Jensen application notes for the Twin Servo. Those notes have much simpler circuits. The official circuitry of the Twin Servo that I build is proprietary and not released to the public.

Any op-amp, even the 990, has limits on how much gain it can provide before distortion starts to increase. This is why the two-stage design of the Twin Servo offers somewhat less distortion and wider bandwidth at very high gain settings than the single-stage design of the M-1.

Thanks again.

John Hardy

audiokid Fri, 10/14/2016 - 10:13

JWHardy

JWHardy, post: 442181, member: 19368 wrote: I try to emphasize the importance of the "impedance ratio", or "turns ratio", or "step-up ratio" (they are all saying the same thing in different ways), and the importance of using the transformer with the lowest ratio if you want the lowest distortion and widest bandwidth. If you want color and flavor, the higher ratio models will be more appropriate.

JWHardy, post: 442218, member: 19368 wrote: Any op-amp, even the 990, has limits on how much gain it can provide before distortion starts to increase. This is why the two-stage design of the Twin Servo offers somewhat less distortion and wider bandwidth at very high gain settings than the single-stage design of the M-1.

John, my question to you is for the passive summing crowd. I'm hoping you are familiar with the Folcrom ( http://www.rollmusic.com/folcrom.php ) approach and can suggest, possibly give a few scenarios in regards to Hardy/ Folcrom combo's? (Please feel welcome to suggest your pre-amps as it is Hardy pre's I am interested in).

example: would a more British sound attribute to the single-stage design of the M-1 ("the higher ratio models will be more appropriate") ? and so on...

Anything you can add towards this would be valuable for us too.

We are thrilled to have caught your attention to say the least. Thanks for chiming in.

JWHardy Fri, 10/14/2016 - 13:06

Chris;

I have never heard any comparisons of the M-1 vs. the Jensen Twin Servo (or either of those preamps compared to any other preamp) that involved the word "British", or any other specific country, etc. A very common type of comment is that my preamps are very accurate, but with a certain quality that they really like. People from all walks of life use them quite successfully, whether it is rock, C&W, jazz, classical, rap, heavy metal, post-nuclear, voice work, Foley, you name it. My preamps work extremely well at very low gain settings, at very high gain settings, and anywhere in between. They perform flawlessly all the way up to output levels of almost +26 dBu where the clipping point is. As long as the signal is not clipping (and there is the "PK" LED on the meter that goes off at +22 dBu to warn you ahead of time), it will sound great. Even at the lowest gain setting, the output level will reach the clipping point before the input transformer even begins to saturate.

Many users have put their entire stereo mix through an M-1 or M-2 or Jensen Twin Servo in order to warm things up a bit, or get rid of the digital harshness that they hear. I don't know the specifics of all of those situations, and I don't know if any of them are using my preamps as make-up gain for a passive summing box such as the Folcrom. They may just be mixing digitally with the stereo mix coming out somewhere in the analog domain, then going through one of my preamps. Lots of differences in how things are processed digitally, some better than others.

Synthesizers and other devices are often put through my preamps to get more gain from them and to warm them up.

Regarding the Folcrom, I had a call from someone in Europe asking about using an M-1 as the make-up gain device. He apparently had tried an M-1 that way, as well as some sort of Neve clone. All I can tell you is, all of my preamps are about a quiet as the laws of physics allow, and they are very accurate, with a certain quality that most people really like. Only you can tell if it meets your specific requirements. Try it. See what you think. If you are only going to need 35-40 dB of gain, the M-1 is a more economical choice and should be as good as the Jensen Twin Servo.

Regarding Neve preamps vs. my M-1 (I guess that would be a British preamp vs. however we might describe an M-1), I have a couple of classic examples of people that strongly preferred the M-1. One of them is represented in a video on my YouTube page:

Another example is a legendary engineer by the name of Jim Anderson. He was recording the Renee Rosnes album "For the Moment" back around 1990 or so. His 4-channel M-1 stopped working in the middle of recording one day. He immediately called me for help. I sent a 990 replacement by overnight delivery so they were back in business the next day. But the rest of the story is: When Jim got off the phone with me, he realized that the M-1 would be out of commission until the next day. So they took the four mics that were plugged into the M-1 and moved them over to the legendary Neve console that they had at A&R Studios (room #2) in New York. Immediately everyone noticed the difference and they decided to quit for the day, to resume the next day after the M-1 was working again. Jim wrote a nice letter to me some time later, thanking me and mentioning: "I'm always amazed when the artists and even producers can tell a noticeable difference." He enclosed a copy of the finished album with the letter. He explained that it was "recorded direct to 2 track Sony Dash 3402 at A&R Studio R-2 in New York. The piano sound is yours. Thank you."

So if you want a lot of color, try a Neve. If you want accuracy with a special certain quality, try my preamps.

Thank you.

John Hardy

kmetal Fri, 10/14/2016 - 18:57

Awsome to have you here John. A freind of mine has 2 M1's in his rack and loves them. Thanks for the informative posts! I have a couple quick questions.

JWHardy, post: 442181, member: 19368 wrote: Since the JT-16 provides only 5.7 dB of voltage gain, Deane no doubt though that it would be a good idea to add a 2nd 990 op-amp in series with the first 990 so that very high gain situations would split the gain between two 990s rather than push one 990 to provide all the gain. If you need 60 dB of gain, 5.7 dB comes from the JT-16, the remaining 54.3 dB must be provided by one 990, or 27.15 dB from each of two 990s. This is what the Jensen Twin Servo does.

Does employing 2 xformers in the design effect the noise floor in any significant way?

JWHardy, post: 442223, member: 19368 wrote: My preamps work extremely well at very low gain settings, at very high gain settings, and anywhere in between. They perform flawlessly all the way up to output levels of almost +26 dBu where the clipping point is. As long as the signal is not clipping (and there is the "PK" LED on the meter that goes off at +22 dBu to warn you ahead of time), it will sound great. Even at the lowest gain setting, the output level will reach the clipping point before the input transformer even begins to saturate.

With some pres known to sound subjectivley better when the xformers get saturated, and your designs known for being 'honest or transparent' are you intentionally trying to avoid the harmonic distortions from xformers saturation? Is there a trade off where clipping a pre like yours would cause a subjective unpleasant, becuase your able to achieve such a high level of clean gain? Is this something mainly controlled by xformer model/design or is it more of an overall design aesthetic that determines the clean gain and saturation tendencies?

I'm in no way trying to say one is better than the other, just curious from a design perspective what the obstacles/tradeoffs might be reguarding clean gain and/or xformer saturation.

JWHardy Fri, 10/14/2016 - 20:07

Does employing 2 xformers in the design effect the noise floor in any significant way?

No. The combination of the low-ratio JT-16-B input transformer and the 990 op-amp establish the noise floor. The JT-11-BMQ output transformer is working at line level, not mic level, with a 1:1 step-up ratio, so there is no change in the noise floor because of it.

With some pres known to sound subjectivley better when the xformers get saturated, and your designs known for being 'honest or transparent' are you intentionally trying to avoid the harmonic distortions from xformers saturation? Is there a trade off where clipping a pre like yours would cause a subjective unpleasant, becuase your able to achieve such a high level of clean gain? Is this something mainly controlled by xformer model/design or is it more of an overall design aesthetic that determines the clean gain and saturation tendencies?

I'm not intentionally trying to avoid transformer saturation. it is simply a byproduct of using the best of the Jensen input transformers (JT-16-B), a great op-amp (990) designed by Deane Jensen to be the perfect match for that input transformer, and the best of the Jensen output transformers (JT-11-BMQ) that is also ideally driven by the 990.

The large size of the input transformer means that it can handle very high signal levels before saturation occurs. By the time the JT-16-B would start to saturate, the output of the preamp would be clipping anyway. Consider that the maximum 20 Hz input level for the JT-16-B is typically +9.7 dBu. An octave above that, 40 Hz (below the low E of a bass), the maximum input level would be 6 dB higher, or +15.7 dBu. The transformer provides about 6 dB of voltage gain, plus the 6 dB of gain from one 990 at its minimum recommended gain (like the M-1 mic preamp), for a minimum gain for the preamp of 12 dB. So an input level of +15.7 dBu would result in an output level from the 990 of +27.7 dBu which is beyond the clipping point of the 990 with +/-24VDC power supplies. In other words, forget about transformer saturation with the JT-16-B.

The large size of the output transformer means that it can also handle very high signal levels without saturating. Its maximum output level is +27 dBu at 20 Hz. The output of the 990 would start clipping before the JT-11-BMQ would start saturating. The only way to cause any significant distortion is to force the output of the 990 to the clipping point. That sort of distortion is not as pleasant as a transformer starting to saturate. Short of the clipping point, everything will sound very accurate, but with a certain quality that most people really like.

I respect anyone's desire to add color. Whatever makes you and the artist happy. But I believe that 98% of the time, engineers and artists would love it if they could simply get their recordings to sound the way the instrument or voice sounded live.

Thank you.

John Hardy

kmetal Fri, 10/14/2016 - 23:13

Wow! Thanks for an amazing reply, it's an honor to hear from one of the brighter minds in the industry. Facinating.

JWHardy, post: 442235, member: 19368 wrote: I respect anyone's desire to add color. Whatever makes you and the artist happy. But I believe that 98% of the time, engineers and artists would love it if they could simply get their recordings to sound the way the instrument or voice sounded live.

As engineers how many times have we heard 'no man, that's not what I sound like'.?

Just out of curiosity, do you prefer certain microphones for they're tendency to be pure? For instance Coles comes to mind as far as 'transparent' mics.

Also how much of a role does the xformer play into the overall sound of a mic? For instance a commercially sucessful co-worker of mine says sm-57's have cheapened their xformer over the years.

Again, out of curiosity, when it comes to DI boxes, do you lean toward active or passive, both?

Sorry for the newb type question I am relatively green to the electronics design end of things, but intrigued. Extremely grateful for any of your time.

JWHardy Sat, 10/15/2016 - 23:29

As engineers how many times have we heard 'no man, that's not what I sound like'.?

Just out of curiosity, do you prefer certain microphones for they're tendency to be pure? For instance Coles comes to mind as far as 'transparent' mics.

Also how much of a role does the xformer play into the overall sound of a mic? For instance a commercially sucessful co-worker of mine says sm-57's have cheapened their xformer over the years.

Again, out of curiosity, when it comes to DI boxes, do you lean toward active or passive, both?

I normally don't make mic recommendations. I have often said "Rediscover your microphones". Long ago I had a customer who "complained" that he was going to have to go back and retry all of his mics after he got one of my M-1 mic preamps. He had been avoiding most of his mics because they did not sound good. When he got his M-1, he quickly realized that it was not the fault of the mics that they sounded bad. It was his previous preamp screwing things up.

How much of a role the transformer plays in the overall sound of the mic will depend a lot on which transformer you are using. This is one of the reasons I posted the comparison chart of the various Jensen Mic Input transformers in my earlier message, to show that even with Jensen Transformers, some will perform better than others, with the lowest impedance ratio model (the one I use, the JT-16-B) providing the lowest distortion and widest bandwidth. Beyond the parameter of impedance ratio (or turns ratio or step-up ratio) you need to consider the size of the transformer because it effects how much signal the transformer can handle. Then there is the core material: is it 80% nickel, or 50% nickel, or 97% iron, or some other material? I consider the JT-16-B to be the best mic input transformer in the world because it does everything right. It has the right impedance ratio, the right core material, the right size, the right details about winding methods and dozens of other details, and it is made by Jensen so I don't have to worry about any of that.

Your question also applies to OUTPUT transformers. Once again, I use the best of the Jensen output transformers, the JT-11-BMQ (look for the JT-11-BMCF on their site). For a line output transformer, the best approach for winding the coils is to use the "bifilar" winding method where both windings are done simultaneously. The coil wire is premanufactured with two insulated "magnet" wires bonded together so that you get absolutely identical windings for the primary winding and the secondary winding. They HAVE to be identical - they are bonded to each other before the winding process is started. Beyond that, the core material is selected 80% nickel, and the transformer is (relatively speaking ) HUGE, so it can handle very high signal levels without saturating the core material. Size matters. The net result is, the JT-11-BMQ has vanishingly low distortion, very high signal level capacity (+27 dBu @ 20 Hz) and bandwidth of 15 MEGAHertz. There are lots of iron-core transformers out there, and they will have higher distortion than the nickel core types. They may not be wound as well. Even the winding equipment can make a difference in terms of consistency and accuracy.

I have no knowledge of any changes that your friend says that Shure might have made to the transformers in their SM57. Being the great company that Shure is, I would think that they would know enough to leave the design alone! the SM57 is legendary and one of the best selling mics of all time (the SM58 is too). One of them is THE best selling mic. Perhaps your friend bought a counterfeit version without his knowledge. There is a LOT of counterfeit stuff on the market these days.

Looking into the details of transformers is important stuff! Pay attention to it!

Regarding DI boxes, I have no opinion. There are clean ones, not-so-clean ones, active, passive, tubes, transistors, etc. A DI box should have a very high input impedance so that it does not affect the frequency response of the pick-up of the guitar or bass being plugged into it. This is the reason DI boxes were created in the first place: mic preamps typically have an input impedance of no more than a few thousand ohms, while a guitar amp typically has an input impedance of around 1 million ohms, for good reason.

Thank you.

John Hardy

audiokid Sun, 10/16/2016 - 00:13

JWHardy, post: 442271, member: 19368 wrote: Long ago I had a customer who "complained" that he was going to have to go back and retry all of his mics after he got one of my M-1 mic preamps. He had been avoiding most of his mics because they did not sound good. When he got his M-1, he quickly realized that it was not the fault of the mics that they sounded bad. It was his previous preamp screwing things up

(y)

JWHardy Sun, 10/16/2016 - 11:46

Thanks so much for your time and patience! I'm gonna spend some time learning about transformers.

For the record lol, my friend is by all accounts an a$$hole, and one of those who doesn't like anything that a) he didn't own in his golden days, b) was made after 1982.

Thanks again John!

Knowing what is going on "under the hood" is a good thing, so I encourage everyone to know as much as they can about audio transformers. There are huge differences.

Regarding your friend's comments about Shure (or about anything or anybody!), I suggest you let everyone know at the time that you are quoting him that he is "by all accounts an a$$hole, and one of those who doesn't like anything that a) he didn't own in his golden days, b) was made after 1982." Or not quote your friend at all. Otherwise, it starts some bad energy toward Shure, etc.

Thank you.

John Hardy

DonnyThompson Mon, 10/17/2016 - 07:33

JWHardy, post: 442271, member: 19368 wrote: Long ago I had a customer who "complained" that he was going to have to go back and retry all of his mics after he got one of my M-1 mic preamps. He had been avoiding most of his mics because they did not sound good. When he got his M-1, he quickly realized that it was not the fault of the mics that they sounded bad. It was his previous preamp screwing things up.

I remember the first time I heard an SM57 through a nice preamp, years ago. It was like it was a totally different mic - but in a very good way.
I was knocked-out by the clarity, the definition, and how "big" it sounded ( "big" is the only word I can seem to come up with to describe it).
I vividly recall thinking at the time, that I would have been completely happy using it to record lead vocal tracks... tracks that previous to that moment of "epiphany", I would have never considered using an SM57 for.

Then I connected a Neumann U89i to it, and I thought, "Well, there it is... right there ... that's what I've not been hearing from this mic ... until now."

-d.