Underlying Distortion Issue.

[Muskratt]

Hi all,

Be some time since I have posted.

I am still having a over abundance of distortion issue in my lead channel. My Clean and my Crunch channels are OK and the crunch has nice separation to it, yet when I engage the Lead channel it is like all distortion with no separation.

What I have do so far I found my Power tube socket were very loose so I re-tensioned them and the amp is way quieter then before and yes I have tried new tubes and preamp tubes as well. I am thinking it is something on the board that is not up to snuff but I need help in locating it. As a note the gain channel ramps up real fast and isn't gradual like it was when I bought the amp new.
It is not under warranty anymore either. I also found a bad or going bad capacitor C-77 100/35 and I replaced it already and still the same issue is there.

Bugera 333XL 212 Combo

JJ KT-77's Quad Matched JJ ECC83S with ECC83s PI Tube

What is the next thing to check as a possibility?

Thank's

[soundguruman]

It's hard to tell without a schematic.

[Muskratt]

I have schematics actually there is some posted on this sight too
http://music-electronics-forum.com/t26094/

near bottom 1st page.

[Muskratt]

I guess I have to take it as I am no longer welcome here.

I see others get answered and I get stonewalled..

[Jazz P Bass]

Who is stonewalling?

Without your assistance in relating what you have done as far as troubleshooting, there is not not much to be added.

I am confused as to what 'separation' is.

[Leo_Gnardo]

I guess I have to take it as I am no longer welcome here.

I see others get answered and I get stonewalled..

Don't take it personally Muskratt, it's probably not you, it's the BuggerA. By separation do you mean it doesn't clean up when you back off the guitar volume, and/or reduce your picking force? If so, that's a common factor in a lot of recently designed & built amps. For instance I have a Fender EVH 5150 here that does like that: select the "lead" channel & no chance of anything but fuzzy buzzy tones. The designers think that's what we want. Well some do & some don't. That's what makes the horse race.

[Muskratt]

So is there anything else I can check to see if a resistor is opened somewhere in the Pre stages? I mean I learn as I go as well but how can I describe it.

I realize it is a Bugera but it was much tighter and cleaner when I first bought it and it slowly started to get worse in time.

Would I yield better results replacing the main Caps with some betters ones, and if so what would be a good set to put in? I have put back a EH 12AY7 back in the V6 (That shares) giving it a less fuzzy buzzy then it was.

I posted the link to the Schem's above.. It is most frustrating trying to get it better then it is now.

[J M Fahey]

So is there anything else I can check to see if a resistor is opened somewhere in the Pre stages?

Nothing points to that kind of problem.

You will repair nothing by replacing caps, mainly because you don´t know if it´s a cap problem or not.

There´s some 72 parts in that channel (yes, I counted them), plus the effects loop which is extra.

And sometimes it´s not a "parts" problem at all, go figure.

Just checked the Lead channel schematis: what you describe is the proper sound it produces.
Very high gain, very compressed, it even has the indamous series diode "noise gate" pioneered by Peavey which is a guarantee that at no volume setting, even the lowest one, you will have clean sound.

Nothing to repair there.

As of "it didn´t sound like that when I bought it", sadly, is more of a Human perception than something actually measurable.

Sorry.

[Chuck H]

This isn't a kind reply or one that is likely to resolve the problem, but I'm going to say it anyway

If anything has actually changed it is most likely something other than the amp. Sometimes an amp can sound pretty good ONLY with new strings, new battery in your active preamp, that one guitar cable with the lower capacitance, sitting in that one room in that one place, while your facing away from the speaker cabinet, etc., etc... The most likely change is in your own perception though. Your ears get use to the tone and then start hearing all the snarky problems with it. Think of it as the "coyote ugly" effect. Last night at the bar that chick was hot. This morning, looking at her in the daylight as she's laying there on your arm your about to chew it off just to escape without waking her.

EDIT: The link for the schematic doesn't seem to work for me.

[J M Fahey]

There´s 2 link "families" there, this one works:
http://music-electronics-forum.com/a...era-333-xl.pdf

[Jazz P Bass]

[QUOTE=Chuck H;339024] Think of it as the "coyote ugly" effect. Last night at the bar that chick was hot. This morning, looking at her in the daylight as she's laying there on your arm your about to chew it off just to escape without waking her.QUOTE]

Hah!

Gnaw, gnaw, gnaw.



"Man she was ugly"

Yeah, but I got laid didn't I?

[Chuck H]

There´s 2 link "families" there, this one works:
http://music-electronics-forum.com/a...era-333-xl.pdf

Ok. And I agree that looking at the schematic the tone should be just as described. Too much gain from too few stages there. When you try to overdrive each stage too far articulation gets lost. Also, the coupling caps are larger than they need to be. IMHE it's this extra LF making long flat clips that causes the buzziness rather than the HF clipping. I would expect this circuit to sound inarticulate and buzzy. For this amp adding more gain stages isn't really an option. The only other thing to do would be to reduce gain and coupling cap size. But then you don't have a lead channel anymore, just another crunch channel.

My suggestion would be to try a clean boost pedal in front of the crunch channel as a lead boost. I use to use an EQ pedal for this so I could bump the mids for the boost which could be helpful here. A little noisy as I recall, but who cares once you're ripping into a lead.

[Leo_Gnardo]

I've had a go at a couple of BuggerA's, circus board peppered with surface-mount parts. Hard to diagnose, hard to repair, hard to modify. One chassis wouldn't fit the box: the box was built out of square. My conclusion: disposable amp. Yank anything reusable - speaker, tubes, knobs, transformers. If you're lucky and the box is built square might save that. Sorry for the dismal report.

Maybe they've gotten better since but the BuggerA's I've seen sound weird & don't lend themselves to support after the sale.

[Muskratt]

Ok. And I agree that looking at the schematic the tone should be just as described. Too much gain from too few stages there. When you try to overdrive each stage too far articulation gets lost. Also, the coupling caps are larger than they need to be. IMHE it's this extra LF making long flat clips that causes the buzziness rather than the HF clipping. I would expect this circuit to sound inarticulate and buzzy. For this amp adding more gain stages isn't really an option. The only other thing to do would be to reduce gain and coupling cap size. But then you don't have a lead channel anymore, just another crunch channel.

My suggestion would be to try a clean boost pedal in front of the crunch channel as a lead boost. I use to use an EQ pedal for this so I could bump the mids for the boost which could be helpful here. A little noisy as I recall, but who cares once you're ripping into a lead.

Alright, Many Thanks Chuck. You describe in a different way, but that is what it is doing. As far as the (don't sound like it used too) I know that all varies from place to place room to room and so forth. I think the other slight tone change is just the speakers have broke in too.

I agree with you one the reduce gain coupling cap and how that would make it another crunch channel. The current pedals I have is a Bad Monkey for a OD and it gives it that extra edge but it is still buried in that buzzy saturation. So I think outside of being able to rework anything I will try to get a boost pedal of some sort and see what that can yields. My other pedal is the Line 6 M9 that has a ton of stomp boxes in it but I have to use either front end or FX loop for it. I can't cross cable or re designate the signal chain like the M13 can.
The amp does sound better since I adjusted the socket tension, it is way more quiet.

I know the Coyote ugly effect I been there done that myself.. Woof... Yeah the next encounter was " naa Hell no.. I did not sleep with that! "

OK big thank here to both of you Chuck and P bass and J H for just hearing me out and answering.

I have loaded that EH-12AY7 in there and that tones it way down and makes it a bit more tolerable as it stands.

Cheers!

[Muskratt]

They resolved most of the Bad Molex issues from around early 2009 I think, but as any amp they are hit and miss. I wont' say it is a real road worthy amp and as others point out that the components are cheap, but that amp can be doable for many.

I can agree it can be called a disposable amp. But only when it is plagued beyond function and cost. Then it time to gut it.. resell or keep for another build.

Cheers!