Peavey Mace Problem

[baddog]

peavey mace problem

ENZO

Thanks again. I ordered new diodes,zener diodes and metal oxide power resistors for the peavey. I was told by the amp tech that worked on my amp prior to my latest problems that this amp is a self biasing amp. is that true? Can i run thiis amp on 4 tubes instead of the normal 6 tubes and if i run it with 4 tubes can i put the other tubes back in later if i sell the amp. Im curently running GT6L6R's (6L6GB) but the schematic calls for 6L6GC's is this a bad idea ?

Thanks
Keith
Mykey Is the bad IC causing the capacitors to buzz ? because i used a piece of tubing and the noise is coming from the filter caps.

[mykey]

ENZO

Thanks again. I ordered new diodes,zener diodes and metal oxide power resistors for the peavey. I was told by the amp tech that worked on my amp prior to my latest problems that this amp is a self biasing amp. is that true? Can i run thiis amp on 4 tubes instead of the normal 6 tubes and if i run it with 4 tubes can i put the other tubes back in later if i sell the amp. Im curently running GT6L6R's (6L6GB) but the schematic calls for 6L6GC's is this a bad idea ?

Thanks
Keith
Mykey Is the bad IC causing the capacitors to buzz ? because i used a piece of tubing and the noise is coming from the filter caps.

any short will cause a buzz, but I'm not sure what you mean by buzz. are you talking about a buzz 60 cycle noise from the speakers? or a mechanical vibration buzz? No, the amp is not self biasing. It does not have a bias adjustment because PV wants you to buy special PV tubes. you can bias it by changing the resistor or installing a bias control, which is recommended.
then you can install any tubes you want.
It's not the zeener diodes usually, or the power resistors. you need to be more specific about describing what's going on.
you made it sound like a preamp problem which is usually what goes wrong with those amps.
yes you can run it with four tubes, 2 tubes in sockets 1 and 2 and two tubes
in sockets five and six. (leave out the two middle tubes) then trade the tubes around till you make sure it's not a bad tube causing a hum kind of buzz.
but then again were not sure what you mean by "buzz"?

[Enzo]

Peavey designed the amp so it would not need to be adjusted. That is all they mean by self-biasing. They aren't selling special tubes, they design it cool so the power amp section will run long term on a set of tubes. The powr amp is loud and clean, the tone is developed in the preamp. They don't want kids messing with bias and burning up tubes and circuit patrs by mis-adjusting. The kid would instantly blame PV. Just about any set of tubes you plug in there will fall into a reasonable bias situation.

ANy current production 6L6 will work there. I think the Ruby 6L6GCSTR tubes work well here, but it is not critical. SOvtek, JJ, whatever. I personally don't buy Groove Tube products, I feel their pricing is predatory and won't support it.

[mykey]

Peavey designed the amp so it would not need to be adjusted. That is all they mean by self-biasing. They aren't selling special tubes, they design it cool so the power amp section will run long term on a set of tubes. The powr amp is loud and clean, the tone is developed in the preamp. They don't want kids messing with bias and burning up tubes and circuit patrs by mis-adjusting. The kid would instantly blame PV. Just about any set of tubes you plug in there will fall into a reasonable bias situation.

ANy current production 6L6 will work there. I think the Ruby 6L6GCSTR tubes work well here, but it is not critical. SOvtek, JJ, whatever. I personally don't buy Groove Tube products, I feel their pricing is predatory and won't support it.

the bias in any class AB amp SHOULD be adjusted for the tubes installed. Just because there is no adjustment does not mean it can't be installed.
The purpose of leaving out the adjustment was to force people to buy PV power tube sets rated for that amp. The amp will ALWAYS sound better if the bias is adjusted correctly.
Ruby tubes, sovtek, No thanks. JJ's are much better. Groove tubes are very good, but the price is too high for most people. anytime tubes are lab matched, the price goes way up. Groove tubes does a really good matching job, and it costs lots of money. Best matching? Amprex Bugle Boy at $425 dollars a set, and worth every penny. most people don't need matching that good, but some appreciate it. We will keep those for our $12,000 Marshall clones.

[baddog]

peavey mace problem

The buzz isn't coming through the speaker & it isnt a physical buzz it's coming from the + side of the 100uf 350V filter capacitors. specificly capacitors C9 & C7. None of the IC's got hot . Everything i have read about removing tubes to reduce wattage says to remove the outer tubes only.

thanks
keith

[mykey]

The buzz isn't coming through the speaker & it isnt a physical buzz it's coming from the + side of the 100uf 350V filter capacitors. specificly capacitors C9 & C7. None of the IC's got hot . Everything i have read about removing tubes to reduce wattage says to remove the outer tubes only.

thanks
keith

well I have seen similar things in PV amps
you most likely need to replace the caps.
call PV 601 483 5365 unless it's been changed
ask them where to get new ones and swap them out
they don't cost much.
changing the zeeners etc. to get rid of a cap noise?
i don't think so.
There have actually been issues with caps in the past
and changing them solved it.
talk to the techs at the factory and get their opinion.
they keep track of those things, it's in Meridian Mississippi.
my only idea is to change them out.
Oh OK you can take out the end tubes or the middle ones.
either way works the same.
but it won't reduce the volume much, just a little.

[baddog]

peavey mace problem

Enzo

What do you think?

thanks
keith

film at 11

[Enzo]

The purpose of leaving out the adjustment was to force people to buy PV power tube sets rated for that amp.

Mykey, that is an utter fabrication. ANother pointless conspiracy theory. The tubes Peavey sells are not selected in any way. They use several brands of tube in prodiction, and in fact are not even installing matched sets into the amps. You may feel that bias is some supercritical adjustment, but in reality there is a wide range of perfectly acceptable bias current. The amp may sound better to your ear at some higher current, but thousands of Peavey amp owners are perfectly happy listening to their amps at lower current levels.

Matching tubes adds anywhere from nothing to at most $2 per tube, depending on where you buy it. Unless you buy from Groove. Then you pay an extra 50%.

Since Groove doesn't make the tubes, most of your Groove tubes will be from Sovtek, China, or JJ anyway.

And a mechanically buzzing cap? If it makes you unhappy, replace it. Peavey will sell you any part you need, but caps are available all over the place.

[baddog]

Peavey mace problem

Enzo

I have GT for my amp already but truth to be told i would have bought a different brand if i had known better. Its great they are reproducing the old style tubes but i dont think the average joe needs to get assraped by their prices. I might just order capacitors for my amp after i try changing the other stuff out . I am planing on selling it and want it to be working great when i sell it. Dammit i hate having a contious

Thanks
Keith

PS parts should be arriving soon

[baddog]

Peavey Mace problem

ENZO
I changed the zener diodes and it didn't take care of the problem but it did even out the rail voltage somewhat. Both are 16.? volts. I guess im just trying to figure out why when im using the foot switch i can get a dirty signal bleading into the channel im using. Is there naything else i can check?

thanks
keith

Would changing the 4558 ic chips with say new JRC 4558D's change the sound of the amp or could one of them be causing a problem.

[Enzo]

If you have a bad 4558, chenge it, but the brand of 4558 you use doesn't matter. And I wouldn't hesitate to use a 4560 or 4580 if 4558s were not handy.

You needed to fix the coltages even if it wasn't part of the problem.

Let's try it this way, which input jacks are you using? If you plug into the Automix, then both channels are live. Plug into either the Normal or the Effects inputs and ONLY that channel is live. DO the individual channels sound OK by themselves, leaving the other channel down? Is the amp OK without the footswitch?

I am trying to follow if you are plugging into one channel and having the other channel still live and adding unwanted sound. Or are you in the automix jack and one of the channels is OK, but the other distorting? Or does one channel just sound bad period?

Look at your schematic. The automix jack simply feeds BOTH circuit inputs. Plugging directly into a channel opens the link to the other channel. If the jacks are working right anyway.

The two channel mix into one at U5A. U17 is the output for the effects channel. Remove that IC and it should eliminate that channel from the mix. U18 is the normal channel output, and pulling it should remove the normal channel from the mix. Both channels were sent to the revern, and the reverb return also mixes in here from U16. Pull it and the reverb disappears.

The footswitch works by turning off any of those chips to kill their function. Also U13 for the phaser.

Let's make it work without the footswitch first. This is really not a difficult amp to troubleshoot sitting in front of me, so once I am clear what your problem is, I know we can fix it.

[baddog]

Peavey Mace Problem

ENZO

I had a extra 4558 and tryed it in the amp but it didn't seem to change the sound at all. Im not sure what affect the 4558 has on the sound of the amp if any. I know they are all the hype in the vintage tube screamer pedals.

The rail voltage is now -16.25 & +16.90 at the zener diodes i replaced

Her is whats happening without the foot switch and my guitar plugged into the normal channel with a clean signal . If i turn the volume off on my guitar and turn the pre gain and post gain to 12 on the channel im using you get that amplified noise that tells you if i turn my guitar volume up my amp is going to be very loud. Now if i turn the pre and post gain to zero on the channel that im plugged into and turn the post and pre gain on the effects channel up to 12 i get that same amplified noise without being plugged into that channel and if i engage the fazer it affect that noise also. I think if im plugged into the normal channel i shouldn't get any noise from the channel im not using . Am i wright ?
Im not getting a guitar signal through the effects channel just the amplified noise.

I think the distortion could sound better ( kind of grainy & thin) but everything i read about this amp says the distortion sucks but the clean sounds good in my opinion very Lynyrd Skynyrd when overdriven.

Now if i plug into the automix channel and have the footswitch pluged in ,I can get a faint distortion signal in the channel that im using from the channel that im not using if i set the pre gain on that channel to anything above 8 and the post gain to 0 . The distortion saignal doesnt get louder if i turn the post gain to 12 it still stays a faint signal. Both channels do this and i can even do it in the combined channel mode . The footswitch is a peavey and it does say Automix on it but i dont think it is the original one for this head. It has a channel switch, combine switch and a reverb switch but no fazer switch option . Im not sure if could be part of the problem but i thought i should let you know.

thanks
keith

[Enzo]

Phasor or not, if the other switches select one, the other, or both channels, it is working.

When you plug into automix, the FS selects the channel(s) you play through by silencing one or the other or neither. Without a FS, both channels are live, so you can turn either channel up to max and listen to its noise at any time. The guitar will of course only come through the one you plug into, or both with the automix jack. The circuit noise through the effects channel goes through the phasir, so I don't doubt the noise sounds phased. Plugging into one channel does not mute the other.

Aside fromthe noise at 12, do both channels work if plugged into? And in automix, can you play through either set of controls and even blend them together? THEN with the footswitch can you kill either channel. Try this. Set the effects on 12 so it is noisy. Plug the guitar into the automix but turn the guitar volume down, all we want to hear is channel noise. Now, by flipping the channel select back and forth, does it switch the noise on and off? You can also turn the efects channel down and the normal channel up and see if it is controllable by FS.

Whuere would you normally set the post controls for playing this amp?

[baddog]

peavey mace problem

The switching is working fine . I can mix the two channels together and it does switch between them fine. Apearantly that amplified noise is normal when im not using the foot switch because Peavey confermed that today.

The only problem i have then is if im useing the foot switch and playing clean on the one channel but have the other channel set to full distortion i can get that faint distortion siganal throughy my clean channel . Peavey also said that the buzzing from the filter capacitors could be normal because of the hi voltage running through them , what do you think ?

thanks
Keith

[Enzo]

I'd agree with them on the preamp, but I'd expect to be able to clean up any hum from filter caps.