Mesa Quad Preamp

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firmani99

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I just picked up a quad preamp on ebay. I set it up and it sounds "ok" but not great. I figured it was probably tubes so I opened it and it has all groove tubes which look brand new. I don't know that they are new but there is dust on everything but the tubes. They look shiny and new. Does anyone use groove tubes? I have heard that they aren't all that great but are they that bad?

Also, I have a mark iv and Mark v so I am familiar with dialing them in. I have tried it in the power amp of my mark iv and of a triple rectifier and in both it sounds just so so. The mark iv sounds ballsier. Does this seem normal?
Thanks.
 
firmani99 said:
I just picked up a quad preamp on ebay. I set it up and it sounds "ok" but not great. I figured it was probably tubes so I opened it and it has all groove tubes which look brand new. I don't know that they are new but there is dust on everything but the tubes. They look shiny and new. Does anyone use groove tubes? I have heard that they aren't all that great but are they that bad?

Also, I have a mark iv and Mark v so I am familiar with dialing them in. I have tried it in the power amp of my mark iv and of a triple rectifier and in both it sounds just so so. The mark iv sounds ballsier. Does this seem normal?
Thanks.

Maybe describe in more detail what you mean, "it sounds "ok" but not great". Also, perhaps post your settings.
Although you've got a IV and V, have you ever dialed in a Mk II or III?
 
No I have never dialed in a II or III.

It is hard to describe but it sounds almost tubby (like a mark iv with the bass knob all the way up) Even with the bass all the way down. And sounds somewhat "lo-fi" if that makes any sense. Also no matter what I do, channel 1 is waaaay louder than channel 2.

I was able to get a hold of the previous owner and he said the tubes have very little use however, I have just discovered that a tube on channel 1 has gone microphonic. I noticed when I put something on top of the preamp while in channel 1. It does not do this on channel 2. Maybe the tubes were damaged in shipping.

So I think I may have found my problem. Hopefully it is just tube related. We will find out soon!
 
firmani99 said:
No I have never dialed in a II or III.

It is hard to describe but it sounds almost tubby (like a mark iv with the bass knob all the way up) Even with the bass all the way down. And sounds somewhat "lo-fi" if that makes any sense. Also no matter what I do, channel 1 is waaaay louder than channel 2.

I was able to get a hold of the previous owner and he said the tubes have very little use however, I have just discovered that a tube on channel 1 has gone microphonic. I noticed when I put something on top of the preamp while in channel 1. It does not do this on channel 2. Maybe the tubes were damaged in shipping.

So I think I may have found my problem. Hopefully it is just tube related. We will find out soon!
I think its a typical issue! The 1st channel is always louder than the 2nd one. Any update on the problem?
 
If you have volume balance problems within the 2 channels, check that :
http://forum.grailtone.com/viewtopic.php?f=5&t=7431
 
If theres nothing wrong with it,the quad should sound/feel like youre plugging or playing thru a real amp"head" so to speak.Ive had 3 of them, all different.Tubes would definitely be place to start troubleshooting.
 
I've changed out the tubes and I've found that it needs a new pot or 2. I am wondering if it is in need of a cap job. Is there any clear cut way to tell?

I can get it to sound decent but when using my Mark IV as a power amp I can't get it to sound any where near as good as the Mark IV on it's own. I am plugging into the loop return and I'm careful not to over drive it.

It is very hard to describe the differences but there is less low end and the low end that is there sounds tubby and loose. It sounds kind of like a badly dialed in mark iv no matter how I dial it in. I am also wondering if I still have a bad tube. Or if its worth having it recapped. I'm not sure, I don't need it so I may just sell it.
 
firmani99 said:
I've changed out the tubes and I've found that it needs a new pot or 2. I am wondering if it is in need of a cap job. Is there any clear cut way to tell?

I can get it to sound decent but when using my Mark IV as a power amp I can't get it to sound any where near as good as the Mark IV on it's own. I am plugging into the loop return and I'm careful not to over drive it.

It is very hard to describe the differences but there is less low end and the low end that is there sounds tubby and loose. It sounds kind of like a badly dialed in mark iv no matter how I dial it in. I am also wondering if I still have a bad tube. Or if its worth having it recapped. I'm not sure, I don't need it so I may just sell it.
IMO I think that before you try to sell it, it might be a good idea to try experimenting with some new tubes. I was once not happy with the sound and fortunately enough it just needed some new tubes! V1 - v3 would do the trick I suppose... Also, have you ever used a parametric eq?
 
I think that you are probably right. And yes I have a parametric eq. I am not opposed to using it but I want to be able to dial in a good sound before tweaking it with the eq. I tried using it again the other day and it randomly cuts out. I think the next step is to replace the pots that are obviously bad as well as replace all of the tubes and then go from there.
 

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