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So, I'm new to tubes, but I'll be replacing the 12AX7 tubes in my Aphex 107 preamp with 12AT7's. I have read on here that they were originally supposed to be in there and the unit performs better with them.

My question is, which brand should I get? I've been looking on here and at distributer's sites. People on here have suggested JJ and Electro-Harmonix. I see that the Mullard 12AT7WA/CV4024 tubes are the most expensive, and I'd assume the best, although this isn't always true.

http://thetubestore.com/12at7types.html

Thanks in advance

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Comments

dvdhawk Tue, 10/13/2009 - 00:11

I just bought a matched pair of Mullard EL34's for an old guitar amp..... veeeeeery nice!

These are the first I've bought from the new company making tubes under the Mullard name. File me under 'veeeeeery satisfied'.

They have a nice warm vintage tone to them, just not the cheapest -but just what I was looking for this old Musicman 65 amp.

moonbaby Tue, 10/13/2009 - 09:12

For my 107's, I've been very happy with GT's. They have great QC, they grade their tubes, and the noise level and consistency has been awesome. Keep in mind that what works well in a guitar amp doesn't always perform the same in a 107...You might contact the support department at Aphex and see if they have any suggestions.

Link555 Tue, 10/13/2009 - 10:12

You might contact the support department at Aphex and see if they have any suggestions

Good advice,

I like the Electro-Harmonix 12AT7WC-EH
I have also used the JAN-Philips 12AT7WC
and the 6201. Mullard is the fancy pants brand, can't say I have tried them.

In reality any should work just fine. Buy some and try them out.

Guitarfreak Tue, 10/13/2009 - 10:47

Can't say that I've used these tubes in a mic preamp, but if they work the same way as they do in guitar amps then it depends on the sound you are going for.

Mullard 12ax7 tubes, like has been said, are slightly warm in the way they respond to low mids, but also have a nice upper presence. I'd assume these would be good for softer vocals that you might find on an acoustic track.

Ruby 12ax7 tubes have a fat warmness to them, great for guitar but I'm not so sure you would like them in a mic preamp as they seem color the tone quite a bit. Then again that rounding softening effect might be just what you are looking for if this preamp is going to be used to track a drum set.

Tung Sol 12ax7 tubes are the clearest tubes I've heard, great if you want to add the tube breakup without coloring the tone. They're a little lighter on the bass end than say a Mullard, but that might be a good thing too.

It all depends on what you want the end result to be.

Link555 Tue, 10/13/2009 - 15:51

The 12AT7 in the Aphex 107 circuit is not used in the standard configuration. There is a current source on the plate trying to bump up the current to compensate for the 48V plate voltage.

The tube in this circuit has a constant plate current based on the output voltage and intergeral negative feedback path to fix voltage output wander.

My point is the tube brand will have less effect in this circuit than most class A circuit without feedback.

anonymous Sat, 05/22/2010 - 17:22

Here is a pair of very sweet NOS KT66 tubes by Emitron. 1950's!! Good as new

[="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220609676755&ssPageName=STRK:MESELX:IT"]Emitron KT66 NOS pair RARE 1950's British Tubes MINT - eBay (item 220609676755 end time May-31-10 15:21:32 PDT)[/]="http://cgi.ebay.com…"]Emitron KT66 NOS pair RARE 1950's British Tubes MINT - eBay (item 220609676755 end time May-31-10 15:21:32 PDT)[/]

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