# Vintage Traynor "Crackle". Help!!



## bcmatt (Aug 25, 2007)

So, I have an old (1976?) Traynor YGL-3a that I've noticed will crackle during a hard strummed bassier note or chord when done with any decent amount of volume. Give it a hard loud chord and the nasty crackling will start about half a second into it. It's like the amp sees a certain amount of power and says, "too much! I'm going to crackle!"

Despite my love and fascination with amps in the last 3 years or so, I have no long-term experience with amps, so I have not been through a whole lot of repairs. I've built and modded a number of amps now, but don't know what it's like to experience an amp aging. I've never even had to replace power tubes (except to try something new). So, diagnosing these things is all just trial and error and guessing.

I swapped through all the 12ax7 preamp tubes and it still does it.

I tried a different speaker cabinet and it still does it.

I tried different guitars and patch cables and it still does it.

I reconnected the NFB wire that I had disconnected (sorry! It really opened up the tone) and it still does it.

It does have a Quad of old Mullard 6ca7 power tubes (possibly the originals), but they still sound pretty full and pretty to me. Is crackling a sign the power tubes are going? Isn't it supposed to also lose some of its frequency spectrum and volume?

I'm thinking I will also try cleaning the tube sockets, but I don't feel like that is it.

Tonight I think I will go try another speaker cable (just in case I used the same one when I swapped cabs)

Any other thoughts from anyone? Is there something obvious that I am missing? Would bad rectifier diodes do this? Could it be a problem with the OT? What are usual causes of this sort of crackling. I don't have an oscilloscope and I live pretty far from a qualified tech that would have one.
Thanks for any help!


----------



## keto (May 23, 2006)

dried out caps? I'd definitely be putting a meter across them.


----------



## bcmatt (Aug 25, 2007)

I don't think so. The caps were replaced about 5 years ago. 
Also, when they go, they make noise sort of consistently. 
This sound only happens when the juice is really surging above a certain volume.
I tried a different speaker cable too. That wasn't it.
Also, the other thing I noticed is that the amp generally has to be warmed up a bit before it happens (just a minute or so of playing first).


----------



## WCGill (Mar 27, 2009)

It's probably current-related or an oscillation. As it is an old amp, I'd check all solder joints first. Cleaning the power tube sockets wouldn't be a bad idea either. Voltage is jumping across a resistance that shouldn't be there and arcing, making your noise (if it's a bad joint or ground). Keep us informed.


----------



## bcmatt (Aug 25, 2007)

WCGill said:


> It's probably current-related or an oscillation. As it is an old amp, I'd check all solder joints first. Cleaning the power tube sockets wouldn't be a bad idea either. Voltage is jumping across a resistance that shouldn't be there and arcing, making your noise (if it's a bad joint or ground). Keep us informed.


Hey, thanks for the help! 
I do believe that there is an oscillation in this amp, but I am unsure as to what can cause one. So, this may be a stupid question, but can oscillations be caused by solder joints as well? 
You see, I don't know how it got an oscillation, but I believe it became evident when I converted channel 1 into a Dumble-style HRM overdrive that switches (completely) in and out of remaining channel. It was a squeal that became evident when the gain and treble were up. I never did figure out how to track it down.
However, even when the amp is played (with the overdrive switched completely out of the circuit) it will do this crackling.
So, do you think these both are attributed to the same oscillation?
Regardless, I want to get rid of the crackle.


----------



## WCGill (Mar 27, 2009)

I didn't realize the amp was modded. Chances are it's an oscillation then. This can't be diagnosed over the internet, sorry.


----------



## bcmatt (Aug 25, 2007)

So, I was reorganizing (with more expensive components) the OD mod section of this amp, and stumbled across a broken 2" wire on an original part of the eyelet board (at the solder joint) that I had not molested. At this point, it was actually causing cutting out of signal altogether. I fixed that wire and that solved some problems.

It now takes some very aggressive gain and treble to get any oscillation type squeals from the OD, so the amp is very useful with some of those HRM type overdrives now.
I had made the NFB switchable on or off from the front panel (with long wire routing). That was causing some noise so I put a 250K pot on the back panel in place of one of the speaker jacks. I basically found the sweet spot and will return the jack and change the resister in series to match the value of what the pot was adding up to. It really opens up the amp in a pleasing way for me and gives the (clean-unmodded)amp some much needed gain.
So, if someone is wanting an idea on modding their YGL for more gain, I'd try this simple resister swap first and see if it gets you where you are trying to go.I'm guessing that the value will be somewhere in the 56k -100K area bumped up from the original 10K, resulting in a decrease in Negative Feedback and opening up the sound a bunch.


----------



## Dustman (Apr 1, 2011)

I just got a 1970 Traynor ysr-1, and it has the same crackle that you speak of. I'll be a gentleman and keep my dirty paws out of her and take it to a pro, maybe busen - he just did my buddies YBA and is doing something to an old National he has as well.


----------



## parkhead (Aug 14, 2009)

crackle on new work = cold solder joints


----------



## bcmatt (Aug 25, 2007)

parkhead said:


> crackle on new work = cold solder joints


sort of - It was a broken wire that was still touching most of the time, but not really connected. Finding it and resoldering fixed that. It wasn't even new work; just an old part of the eyelet board that must have been bumped or bent over the years or something.

By the way, swapping out the 10k NFB resister connected to the output jack for a 100k resister really opened up the amp and improved the tone for me, giving some much needed gain to this amp in stock form. Worth trying for anyone with a YGL that doesn't want to always be perfectly clean.


----------



## parkhead (Aug 14, 2009)

excellent

what you found would have been my second suggestion along with severed component lead that still looks good 

either way that crackling sound is the sound of the signal "jumping a gap" in the circuit 

p


----------

