a few basic questions that need answers

Posted: Thu Dec 06, 2007 10:39 pm

hey all,
i dont really know much about amp setup and all that, even though ive been playing for about 15 years, ive just been a bedroom guitarist and the occasional jam seshes at my drummer cousins place.
ive got a few basic questions that need answers.
first of all, is a line out the same as a preamp out jack? for example my marshall valvestate 65r combo has a line out, and i know its a solid state poweramp, with a valve preamp, so if i use the line out is it only using the preamp? or is there a difference?
also the marshall has an FX loop but when i try to run a pedal through it it sounds kind of muffled and has no power, ive checked my leads and mucked around with the amp settings FX volume and all that. but really its just shit, compared to running the pedal into the guitar input. also ive got a chinese Biyang BY 2203 50watt amp which is a copy of the marshall JCM800 2203, which is a F'ing awsome amp for the price. it has an FX loop too and when i try run a pedal through that its kinda the same as the marshall vs65r, just shit, and when i try turn up the master volume it just has no power, and sounds muffled, even though i have the gain turned down i can tell its running through the gain channel but sounds shit compared to when i run it through the guitar input. i cant understand why anyone would want to use an effects loop if thats the results. i think i must be doing somthing wrong, can somwon shed some light on the situation?

also i read some reviews on the marshall 2203, and there was some talk about using an attenuator with them, i couldnt figure out what they were talking about, whats an attenuator and what does it do?
id appreciate any help you can give me.

Posted: Fri Dec 07, 2007 7:33 am

Welcome to RO, Riffer:
First off, the "Preamp Out" and a "Line Out" are essentially the same thing.
Using the preamp output to feed an extra power amp or a recording device (hopefully through a DI box) is OK to do. The downside to this is that you are bypassing the speakers in the rig. These act as "filters", as they are voiced for the guitar's frequency range, and tend to not reproduce the very low and high frequencies that add trash to the sound.
Since the preamp out is not doing this "filtering", you end up with a gritty, harsh sound from it, even if the manufacturer says that it's "voiced" for guitar, the direct output tends to sound like crap. Stick a mic in front of the speakers if/when you want to record the amp.
As for the FX loop, these vary wildly between amp manufacturers and the type of FX you are patching into them. Basically, if the FX are stomp-box types, don't bother with the FX loop. The operating levels and impedances that the FX loop jacks are designed to work with are for rack-mounted "line level" FX units, not "guitar level" boxes. Those stomp box FX do not have enough "juice" to feed the the power amp section of your guitar amp. This is why the tone/volume are whimpy and dull. Skip using the loop unless you are using a decent line level rack unit.
Finally, a power attenuator is designed to be used with a "real" tube amp, where you want to drive the power tubes to their saturation point for sweet harmonic distortion. The attenuator lets you do that and at the same time "attenuates" the actual power reaching the speakers to a fraction of the power the amp is generating. This results in low volume levels so that you aren't blasting out the neighbors. You have no need for such a device because your amp is a transisor amp that sounds horrible when maxed out, comparatively speaking.

Posted: Fri Dec 07, 2007 7:43 pm

thanks for that moonbaby, i know what you mean about running the line out on the amp straight into a computers sound card, i did that a while ago on an old computer i had, i was using cool edit pro recording software, and i was able to get some likeable results doing that, but yeah for the most part too harsh and buzzy.
i was trying to use stomp boxes through my fx loops, so theres the problem.
the biyang 2203 amp i was talking about is an all tube amp, like i said its a copied for the most part from the marshall JCM800 2203, and its sound backs that up, its got 3 12ax7 tubes in the preamp, and 2 6L6 tubes in the poweramp. im not sure i need an attenuator for this one, because it has a preamp, and master volume, also a switch to run the power tubes in 30w or 50w, modes. i dont know much about the marshall versions of the 2203 all i know is i think they were a one channel amp.
check out www.biyang.com.cn, these guys make some pretty good stuff for a chinese manufacturer.

also i was thinking about just getting one of those usb condenser mics, to hook up to my laptop, just for some basic home recording. nothing serious i just like to improvise alot, and if dont record it, i can do some cool stuff and forget about it, and its gone forever, and i want to make my own backing tracks to solo over, but i dont want it so sound shit either.
do you think a usb mic will give me acceptable sound quality?

Posted: Sun Jun 01, 2008 8:56 am

Depends on what your level of acceptable is.
I use a Behringer XM8500 Ultravoice mic and an Edirol UA-25.
It's acceptable to me because _everything_ I record with it is just like a sample of the room. A room where improvised music happens.
Sure, sometimes I wish after laying down 30 mins of gold moments that I had everything multi-tracked with million dollar precision so I could edit, edit, edit, produce, edit, edit produce edit produce edit edit edit edit produce produce eat edit edit edit edit edit and so on until I had the greatest record in history that all people will buy and keep listening too and have to re-buy over and over again whilst still controlling rights to publishing so I get some coin and can eat again.
Sometimes, I wish I could fly.

Posted: Sun Jun 01, 2008 3:40 pm

A preamp out and a line out MAY be the same thing, but they may be different. Depends on the amp. A preamp out will always be before the power section, whereas a line out may be there, or it may be a speaker simulation circuit, or a padded down circuit line directly connected to the speakers, to get the entire amp's electronic sound, minus the speaker, to run or record direct. So, it cannot be assumed that it IS always the same.

An effects loop also depends on the amp. It could be in series between the preamp and amp, thereby routing the entire signal through it. It may be in parallel, with the effect intensity depending on a mix knob and effects settings that are added to the unaffected signal. So, you cannot assume either.

Both of these should explain in the manual.

Lastly, usually only time-based effects go into an effects loop (delay, chorus, flange, phaser, reverb, etc.), while distortion, wha-wha and compression goes into the front end. Some people will, though, run a POD or similar into the power amp in, bypassing the pre altogether, and using all the distortions and effects from that unit like that. if you are trying to run distortion in an effects loop, try it in front of the amp, with only time-based effects in the loop. Distortion boxes usually provide gain, and when you run a bunch of preamp gain into one, that may be making it wacky. Time-based effects usually don't have much of a dedicated gain circuit, only speed, depth, etc.

Most time-based guitar stompboxes are perfectly content in most guitar amp effects loops. That's what they put the loops in there for.

Kapt.Krunch

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