L-pad attenuator - smoke

[wavley]

Jeez, what a clown!

I've never seen a Traynor lose a transformer, but it's not like I've worked on hundreds of them.  They're not all that common around here.

Off the top of my head, I don't know what resistor you're referring to that protects the OT.  Can you elaborate?

I've never seen a Traynor lose a transformer other than this one, I don't know what he did.  They're pretty massive Hammond iron.

The 180 ohm resistor on the speaker jack is there to help keep the transformer from blowing up, there's other ways of doing it too... Shorting jack for the speaker, diodes on the primary...  I don't dig the diodes on the primary thing (I'm looking at you Peavey and Ampeg) because they short all the time under normal use, I'd say I see it in an amp at least every two months, it's crazy because a lot of them are combo amps with working speakers so they didn't lose the load.

[thermionix]

Ah yeah, looked again and I see that 180.  Was checking only the primary side before.

[brianq]

Ever thought of buying a real attenuator? I got one used for $100. Amp repair will cost you more than that if you fry something. Echoes from my mentor: "Use the right tools for the job & you'll have no regrets". Transformers ain't cheap Lol


Sent from my iPad using Tapatalk

[PRR]

The 180 on Traynor secondary is dubious. It may help for light clipping while unloaded; it won't save you if you beat it wondering why there's no sound.

Shorting jack is entirely OK for self-biased tube amps. (Does not save you if you plug the amp and forget to plug the speaker.) Fixed-bias amps worked extremely hard (as the big Traynors do) can melt the tubes if abused into a short (same as an un-protected transistor amp).

[thermionix]

Back in the early 90s I had a Peavey 5150 head for a short while.  I think my second tube amp.  One day I was getting no sound, so I cranked it up all the way and could only barely hear it.  Then I noticed the cabinet wasn't hooked up!  Somehow the amp survived, I guess I turned it off quickly enough, or maybe there's an idiot load built in.  Did you know power tubes make a sound acoustically when cranked all to hell?  I don't recommend finding out.

[Ben N]

Another Traynor fan here. I've got three of them: a YSR-1, a YBA-2 (6V6), and a YVM-1. I'm still kicking myself for the YBA-1 in a local pawnshop that I let slip through my fingers about 15 years ago. Change the volume pots, and those things are Marshalls with better iron.

If you can kill a Traynor OT, then all I can say is, you've got skills.

[thermionix]

The one I have here now for a cap job is a YBA-1.  I'll tell it you said hi.

[wavley]

The 180 on Traynor secondary is dubious. It may help for light clipping while unloaded; it won't save you if you beat it wondering why there's no sound.

Shorting jack is entirely OK for self-biased tube amps. (Does not save you if you plug the amp and forget to plug the speaker.) Fixed-bias amps worked extremely hard (as the big Traynors do) can melt the tubes if abused into a short (same as an un-protected transistor amp).

This is why I'm in the habit of flipping an amp off instantly when I don't hear sound and I check the speaker before I do anything else, especially because there's any number of amps with absolutely no protection.

Maybe those ways might not be the best way to do it, but I sure do replace a lot of flyback diodes in otherwise functioning amps and I haven't replaced an output transformer in a vintage Fender or Traynor in a long time, well, except for the Champ sitting under my bench with a new OT waiting to go in, but the tab on it's speaker broke off and the tinsel wires twisted around each other causing goo from the OT to drip out onto the speaker frame so I'm going to cut that one some slack and not really blame the amp for that.

Is there a better way to do this?  Honestly, if there's a good way to protect OT's I'd consider making it a thing at my shop akin to the "no tube amps leave the shop without grounded power" rule we have.  I am so very tired of seeing Ampeg V-4s with shorted flyback diodes, they're so heavy to lift up onto a bench

Back in the early 90s I had a Peavey 5150 head for a short while.  I think my second tube amp.  One day I was getting no sound, so I cranked it up all the way and could only barely hear it.  Then I noticed the cabinet wasn't hooked up!  Somehow the amp survived, I guess I turned it off quickly enough, or maybe there's an idiot load built in.  Did you know power tubes make a sound acoustically when cranked all to hell?  I don't recommend finding out.

The 5150 has flyback diodes on the primary, as much as I complain about them... they do save amps.

Ever thought of buying a real attenuator? I got one used for $100. Amp repair will cost you more than that if you fry something. Echoes from my mentor: "Use the right tools for the job & you'll have no regrets". Transformers ain't cheap Lol


Sent from my iPad using Tapatalk

This is an option too, the Weber ones are nice and have a speaker motor for a more reactive load, a line out, and some corrective EQ.  I played a THD on a guy's JTM-45 reissue that didn't sound too bad (It did at living room volume, which is why I ended up building him a 4 watt single ended amp with a master volume)

I had an Altair PW-5 when I was a kid, didn't even like the sound then, the only thing those are good for is making toast.

I'm probably the wrong guy to ask, I have little amps for pushing hard and big amps for being clean.

[anotherjim]

On the subject of OT protection...

I worked on a Marshall combo for a friend recently. He told me that in the past it had need a new OT. He couldn't say if anything was done to find out why the OT had blown. The new OT was still good, that wasn't why it needed looking at, but I thought it was worth investigation.

In this amp, it's got isolated DPDT switching in the speaker jack sockets. Contacts here complete power tube cathode connection only if there's a plug in them. Take the plug out and the OT primary circuit is effectively switched off.  He told me he never used external speakers anyway, and the combo speaker plug had always been in the normal socket.
Examination of the socket showed it was fine, nothing jammed, dirty or welded. The speaker plug being a moulded on type set alarm bells ringing. I found that if I worked the cable close to the plug, then tip continuity could be lost. I carefully cut off the plastic and found the tip wire was relying entirely on the plastic to hold it in contact with the tip.
I think I may have found out why the OT had blown. Replaced with a Neutrik right angle plug - expensive but the best.

BTW, the rest of it's troubles was down to dirty normalizing contacts on all the jacks for inputs and fx loops. A pro repairer had told him it needed  - New tubes, a re-cap and new plate resistors - but I guess that's how they make a living.

[thermionix]

Overmolded cables are annoying, and fail frequently.  On the dirty jack contacts, a very common amp problem is FX loop return jacks.  A lot of players never use the loop, and the dust and oxidization can eventually add up to the contact going open, and cutting the sound completely.  So hit your loop jacks with a little deoxit occasionally, especially if you never use the FX loop.

[christien]

Just revisiting this, is it possible to wire two l-pads in sequence?  Would that effective double the reduction capability, without overheating them?  (assuming they were both set at 50% reduction or less)

[christien]

anyone?

[PRR]

Yes.

[christien]

Awesome, thanks!