Bass amp troubles

[lol]

Hello,

I have a Trace Elliot v type 5001. It is a hybrid amp, 2 preamp tubes and solid state power amp. The issue I am having is there is a buzzy sound that seems to follow when playing certain notes. I know its not my basses as the issue happens with all of them. I've tried different preamp tubes and that did not solve the issue. I also used deoxit on the pots and all inputs and the issue persists.

Any idea what the problem could be?

Thanks!

 

[Massarea Whippins]

That amp has a Mosfet based power section. From your description of "buzzy sound that seems to follow when playing certain notes" My guess that the Mosfets need to be re-biased. I have no experience with a V-Type 5001, but the Ampeg SVT 3-PRO is also Mosfet output, and is rather notorious for the same problem with the same symptoms. I also note that many/most "amp techs" seem to be clueless about to diagnose and fix this, so I researched and learned how to bias my own 3 PROs (I have three). It just takes a good multimeter and a steady hand. I'm not saying I'm right about your V-Type 5001, but it's worth looking in to. Good luck!

 

[lol]

That amp has a Mosfet based power section. From your description of "buzzy sound that seems to follow when playing certain notes" My guess that the Mosfets need to be re-biased. I have no experience with a V-Type 5001, but the Ampeg SVT 3-PRO is also Mosfet output, and is rather notorious for the same problem with the same symptoms. I also note that many/most "amp techs" seem to be clueless about to diagnose and fix this, so I researched and learned how to bias my own 3 PROs (I have three). It just takes a good multimeter and a steady hand. I'm not saying I'm right about your V-Type 5001, but it's worth looking in to. Good luck!

Thanks so much! I do believe this amp does have adjustable bias for the power section. I'll pop it open and do some research to see how to tackle this.

Thanks again!

 

[Carol-AnnAmps]

I concur that MOSFETs bias has drifted and that can cause cross-over distortion which can sound like what you describe. Also a parasitic oscillation way above audio can cause these type of symptoms in the audio spectrum but it often also feels like there's some loss of overall volume with that too.

 

[lol]

I concur that MOSFETs bias has drifted and that can cause cross-over distortion which can sound like what you describe. Also a parasitic oscillation way above audio can cause these type of symptoms in the audio spectrum but it often also feels like there's some loss of overall volume with that too.

Interestingly, when I had tried different preamp tubes, there was less volume with the replacements, and the buzzy noise was less prominent. With the tubes that were already in it, there is more volume and thus the buzzy noise was more of an issue.

 

[lol]

So I decided to run my tech21 VT rack preamp into the fx loop. The buzzing is gone… since the preamp of the trace Elliot is bypassed, does that mean the issue is actually in the preamp and not the power section?

Excuse the retarded question.

 

[lol]

Well the noise has come back, even with using the tech21 vt preamp. So I guess the issue is indeed in the mosfet power amp.

Man I can't catch a break playing bass. I've got 4 bass amps all with their own unique issues. I just want to plug and play and seems that is just too much to ask for. Actually makes me want to throw in the towel...

This has the bipolar bear circuit so if the issue is beyond just bias drift, then I am kinda boned...

I'm just going to start putting money aside to get my mesa mpulse 600 fixed. Got nothing reliable to play through until then but whatever.

 

[japetus]

Get the Mesa fixed and don't look back

 

[lol]

Get the Mesa fixed and don't look back

Yeah, that seems to be the wise thing to do. That mesa was the only one I paid money for, while the others I got in trades. Lasted me a good while before it crapped out. My old tech is back in town and he did say he is willing to look at it.

Picking up the bass though has been nothing but a nightmare. Burned on deals, equipment shitting out left and right. I know I'm being dramatic about throwing in the towel, but believe me it's been just headache after headache.

I played guitar for 21 years and I rarely had issues with my gear.

 

[lol]

I'll probably list the tech21 VT preamp for sale. That'll help me get the mesa fixed.

 

[Floyd Eye]

Depends what your goal is.
It’s not much different than guitar gear. I mean you have a lot of options. Buy an SVT II non pro and an 810cl. Or a Fender rumble.

 

[lol]

Depends what your goal is.
It’s not much different than guitar gear. I mean you have a lot of options. Buy an SVT II non pro and an 810cl. Or a Fender rumble.

Apart from funds being limited, I don't want to risk acquiring another oversized paper weight lol. Cab wise I have an old fender 2x15 cab.

Just going to have the mesa fixed and be done with it. That amp sounded great when it worked.

 

[Floyd Eye]

Apart from funds being limited, I don't want to risk acquiring another oversized paper weight lol. Cab wise I have an old fender 2x15 cab.

Just going to have the mesa fixed and be done with it. That amp sounded great when it worked.

Like I said, totally depends what you’re trying to do.

 

[lol]

Like I said, totally depends what you’re trying to do.

Nothing fancy, I just want to goof around and play. Not in a band and no intentions of being in one.

 

[Rottweiler]

Nothing fancy, I just want to goof around and play. Not in a band and no intentions of being in one.

I picked up an Ampeg rocket bass 210 combo for just that. Casual jams. Lightweight and much more reliable than my old Ampeg. They are solid state, but affordable and sound halfway decent.

 

[Floyd Eye]

I picked up an Ampeg rocket bass 210 combo for just that. Casual jams. Lightweight and much more reliable than my old Ampeg. They are solid state, but affordable and sound halfway decent.

I've owned 4 or 5 SVTs and they've all been reliable as hell.

 

[311boogieman]

So I decided to run my tech21 VT rack preamp into the fx loop. The buzzing is gone… since the preamp of the trace Elliot is bypassed, does that mean the issue is actually in the preamp and not the power section?

Excuse the retarded question.

Never played a bass guitar let alone a bass amp so take this with a grain of salt. The troubleshooting is still very similar to electric guitar as @Floyd Eye mentioned. For reference I have a Peavy Vypyr 60 that has a tube power section and a (Transtube) solid state preamp.

Just because you put the Tech21 in the fx loop does not mean that the rest of the Trace Elliot preamp is not in play. Is there some documentation that says it is absolutely 100% bypassed? I'd find that hard to believe. Fx loops are generally after the preamp and before the power amp sections. The fact that changing the preamp tubes made a difference (although not fixed) proves that out. I'm going to guess that there is a bad preamp tube socket or pin or trace (no pun) to the preamp somewhere. The different notes thing is troubling, but I've also experienced that with other amps and such.

If you have some Dioxit or Electroncts Contact Cleaner spray the preamp tube pins and work the tubes in and out of their sockets. You also might be able to open her up and look at the board etc.

Lastly, if it is not working correctly, I personally would not feel comfortable selling it to someone without notifying them of such first.

Best of luck my friend.

 

[lol]

Never played a bass guitar let alone a bass amp so take this with a grain of salt. The troubleshooting is still very similar to electric guitar as @Floyd Eye mentioned. For reference I have a Peavy Vypyr 60 that has a tube power section and a (Transtube) solid state preamp.

Just because you put the Tech21 in the fx loop does not mean that the rest of the Trace Elliot preamp is not in play. Is there some documentation that says it is absolutely 100% bypassed? I'd find that hard to believe. Fx loops are generally after the preamp and before the power amp sections. The fact that changing the preamp tubes made a difference (although not fixed) proves that out. I'm going to guess that there is a bad preamp tube socket or pin or trace (no pun) to the preamp somewhere. The different notes thing is troubling, but I've also experienced that with other amps and such.

If you have some Dioxit or Electroncts Contact Cleaner spray the preamp tube pins and work the tubes in and out of their sockets. You also might be able to open her up and look at the board etc.

Lastly, if it is not working correctly, I personally would not feel comfortable selling it to someone without notifying them of such first.

Best of luck my friend.

Well, it may not be 100%, however to avoid stacking the standalone preamp along with the amps preamp, you run the preamp output into the fx return. On most amps I've done this with, the controls on the amp typically do not do anything aside from the master volume.

However, I did test this on the trace Elliot and the amps controls still change the tone. So in this particular case, it is absolutely not bypassed completely.

I've sprayed the jacks and sockets and what not with deoxit, and unfortunately it did not help any.

As for selling the amp itself, I am unlikely to do so as I wouldn't want to sell an amp that doesn't work properly. That's why I still have my other non properly functioning gear. The bipolar bear circuit is also apparently notoriously unreliable and difficult to fix, if at all. There is a replacement board made by a UK company but looks as if they have been out of stock for a while. So they may not even make it anymore.

The tech21 preamp on the other hand does work fine though, and if I get my mesa fixed I wouldn't be using it, so I figured I'd off load it.

If anything, when I feel like getting back into tinkering with an amp circuit, I'll try to figure out the whole biasing the mosfets thing. Can only hope that is the only issue. The tech I know only works on tube amps. Hybrids may be fine though, considering he's willing to look at the mesa.

 

[Floyd Eye]

Well, it may not be 100%, however to avoid stacking the standalone preamp along with the amps preamp, you run the preamp output into the fx return. On most amps I've done this with, the controls on the amp typically do not do anything aside from the master volume.

However, I did test this on the trace Elliot and the amps controls still change the tone. So in this particular case, it is absolutely not bypassed completely.

I've sprayed the jacks and sockets and what not with deoxit, and unfortunately it did not help any.

As for selling the amp itself, I am unlikely to do so as I wouldn't want to sell an amp that doesn't work properly. That's why I still have my other non properly functioning gear. The bipolar bear circuit is also apparently notoriously unreliable and difficult to fix, if at all. There is a replacement board made by a UK company but looks as if they have been out of stock for a while. So they may not even make it anymore.

The tech21 preamp on the other hand does work fine though, and if I get my mesa fixed I wouldn't be using it, so I figured I'd off load it.

If anything, when I feel like getting back into tinkering with an amp circuit, I'll try to figure out the whole biasing the mosfets thing. Can only hope that is the only issue. The tech I know only works on tube amps. Hybrids may be fine though, considering he's willing to look at the mesa.

Just ditch the Mesa and buy any power amp and put the tech 21 in front of it. Problem solved.

 

[lol]

Just ditch the Mesa and buy any power amp and put the tech 21 in front of it. Problem solved.

Too late, as I just sold the tech21 lol.

I do have an ADA B500B power amp which I did use with the tech21. Up until the ADA began to malfunction.