Traynor YBA-1 But Which One?

[dorrisant]

I have what seems like a '68 YBA-1... Well, the pots say '68 anyway. No serial number anywhere. I can't find a schem that looks right. Blindog posted the picture (at the bottom) that looks just like mine on this post:

http://ampgarage.com/forum/viewtopic.ph ... sc&start=0

It has a solid state bridge rectifier with a choke, a 180 ohm 20w across the output and the shared cathode resistor and cap at the input stage.

Does anyone have a matching schematic? Maybe Blindog has the original schematic from before his mods.

Also, it came with a 2x10 combo cab, which I find hard to believe would be stock. The only combos I've seen were never 2x10. Anyone have any info?

Mine doesn't have the original OT. Having trouble identifying that as well. Also, it had crispy filament leads from the pilot all the way into the bellhousing of the PT. I opened up the PT and cut the leads out. I brought it up on a Variac and let it sit at 125vac for about an hour. I watched the temperature of the laminations rise from about 70℉ up to about 83℉ over that hour. Other than a buzz from the loose laminations there was nothing significant... No smoke. I think I can attach some new leads and use it as is. Of course I want to use the original PT if possible. Any suggestions or thoughts?

Is this one of the better circuits from Traynor? Should I seperate the cathodes of V1, or leave it? I don't want to screw it up if it sounds as good as some of the reviews I've read... "Holy Grail Tone" has been mentioned in relation to some of the YBAs. Besides, I don't want to change those mustard caps if I don't need to.

Tony

[Stevem]

I have a ton of Traynor schematics and I will check tonight for you, but in regards to that toasty PT winding I do not know that I would trust it, it may be best to not use that winding that way if it is, or does short to another winding the fact that it is un-hook will not make for a issue!
You can then just add a separate PT just for the filaments.

[dorrisant]

Thanks for looking Steve. I figure I will try the filament winding with new leads... If that don't work I have several 6.3vac TXs on the shelf. So I'm not dead set on using it, I just want to try to save it if I can.

Tony

[martin manning]

Letting it run unloaded as you did was a good test, and it sounds like it passed. If the filament winding had shorted turns it would get hot, and if it did you would not solve that problem with an outboard filament transformer.

[Stevem]

It s quite possible that the filament could have shorted to another winding, but not itself,which in that case leaving it un-used will allow you to still use that PT

[randalp3000]

lots of good info and schematics here if I remember correctly
http://www.lynx.bc.ca/~jc/traynorSchmArchive.html

more
http://www.prowessamplifiers.com/schematics/traynor/

more more
http://traynoramps.com/support/manuals_spec_sheets

[dorrisant]

Thanks for the direction guys. I didn't mention that I had checked for shorts to other windings and found no continuity. When testing the different windings a DC resistance test shows zero ohms on the filament winding.... But so do most of the filament windings I've ever checked. My L/C/R meter measures AC resistance and showed a good coil. I thought any short would have caused excessive heat, thanks for confirming that Martin! I figure the small temperature rise might be due to the vibration of the laminations...?

Now if I could just figure out what is that OT is worth keeping or not. Maybe I should post in the Sale/Trade section for an original.

Thanks again,
Tony

[Chris G]

Hi Tony,
The YBA came a few different ways. There was a YBA-1/ w/EL34's and Tube Rectifier. EL34'S with a solid state rect. and The YBA-1A.. The 1A came stock with 7027's or 6550's (pair). I have had many versions of each. The one I have now is a 1A...set up for guitar...very loud and clean...so I ramped up the gain a bit, added a line out...bad ass for sure.

[martin manning]

I figure the small temperature rise might be due to the vibration of the laminations...?

Primary resistance and eddy current losses.

[Stevem]

The only thing I can find with that 237 code on that OT is that it is made by Gowonda in N.Y!

[didit]

[...] it came with a 2x10 combo cab, which I find hard to believe would be stock. The only combos I've seen were never 2x10. Anyone have any info?

[...] Mine doesn't have the original OT.

Excellent advice already from the usual suspects on most of your asks. My take is that filament winding will be OK, but I'm puzzled about crufty insulation. Opening up the end bells and replacing with fresh correct gauge wire would be my suggestion. When you have it open you might be able to see (or possibly even smell) any evidence of serious overheating. Hammond Mfg was the original transformer source and still make replacements. The correct OT for YBA1 is 1750G. Not cheap as Pete Traynor over-engineered those things. And perhaps the current replacement is fine match.

You might find some answers to dating it and matching standard cabinets at the Velvet Black site here -- http://www.0rigami.com/vb/. The Traynor Marsland speakers were generally underwhelming and the one real weakness for the amps. They did make a 6x10" that I'd like to get my hands on. I've never found Traynor 12" drivers worth keeping except as "originals" in a box.

It's a fine amp in the general Bassman-Marshall class from that era, albeit a whole lot less famous.

Best .. Ian

[Cliff Schecht]

I've had to re-engineer one or two Traynor's. They were kind of a mess when I got them although I don't remember what was from the guy I was fixing it for or from the factory (both did some naughty things that had to be removed/reworked). After a bit of cleanup and circuit tweaking though that amp was an absolute monster. SS rectifier EL34 version was what I worked on. I'm visiting the owner sometime soon, that amp eats his vintage Marshall's for breakfast!

[gui_tarzan]

This is the schematic for my YBA-1A, circa 1969-70. I found several different schematics for the "1A" while researching mine. Yours doesn't have the dual-diodes tied across the output tube (6CA7) cathodes on the right side of the circuit board like mine did and I don't see your second stage filter caps or fan cord so it's obviously another variant. If yours is a '68 it could be the standard YBA-1, not a 1A.

It's widely known that Pete (Traynor) did a lot of circuit tweaking through the years as is demonstrated by the number of different schematics for the same models.

The layout is one I drew based on my stock circuit. As you can see there are differences.

[dorrisant]

Thanks for all of the tips and advice! I have looked through all of the schematics that were posted above... still can't find it. Most of the Schematics I saw had full wave rectifiers, this one has a bridge... that eliminates most of them right off the bat. I will just go ahead and draw it up when I get some time.

All things read and seen point to '68 so that's good enough for me. Has anyone seen a Traynor combo cab like these pics? It is a 2x10. I don't think the green was original. The piping looks like they put it on with their eyes closed.

Looks kinda Voxy to me.

Tony

[M Fowler]

I have this schematic YBA-1