Traynor YBA-3 Custom Special

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Traynor YBA-3 Custom Special

Postby JC103 on Fri Jul 01, 2016 5:43 pm

I have a pair of these beasts dating from 1969 according to the filter cap dates. This is the version of the circuit with the choke transformer. The power and output transformers are absolutely huge!! God bless Pete Traynor for overbuilding these amps, they are truly bulletproof. I am pretty sure that I will not run into any problems here, but I am looking for opinions on how "safe" it is to run speaker cabs that are either 4 or 16 ohms on the 8 ohm OT? I have had the OT measured and it is indeed 8 ohms. However no one on the internet can agree if it is safe to run cabs rated one step beyond the 8 ohm rating in either direction. Some say only use a 16 ohm cab, others say nope, only 4 ohms is safe. Traynor even tells people 4 ohms is safe if you email them. Bass players on talkbass.com have been running them into 4 ohm cabs for 20+ years and they are still kicking. I am aware that the speaker jacks on these were originally wired in series. I have one cab that is 8 ohms, so no problem there, but the other is currently wired for 16 ohms. The amp on the left sounds and perform fine when run with the 16 ohm cab. There is way more volume on tap than I'll ever need, I hardly ever get over 2.5 on volume knob. Considering these can put out 180w on a scope at full volume, I think I'm safe running them at conservative levels. Are there any Traynor experts out there that can offer some clarity to the situation?

FYI: I run these amps in stereo, so one cab per amp.

Speakers in the left cab are Eminence Lynch Super V12's wired in series for 16 ohms (300w).
Speakers in the right cab are Eminence Reeves OEM Vintage Purples wired in parallel for 8 ohms (150w).

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Last edited by JC103 on Sat Jul 02, 2016 6:10 pm, edited 2 times in total.
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Re: Traynor YBA-3 Custom Special

Postby mozz on Fri Jul 01, 2016 8:19 pm

Not familiar with that model schematic but i have a YBA-1A with the massive transformers and for all its life it was run with a 4 ohm cabinet yc-810. Mine is not marked on the back how many ohms. 2 original el-34's and it still puts out over 80 watts clean. Do you have the numbers from the output transformer?
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Re: Traynor YBA-3 Custom Special

Postby JC103 on Sat Jul 02, 2016 6:15 pm

I actually owned a pair of those YBA-1A MKIIs many moons ago. I seem to remember they could easily put out 90w at full power. High plate voltage in the realm of 530v (if I remember correctly) is how they do it. The YBA-3's are designed the same, just doubled up with 4 x EL34s. I'll check the OT part number next time I have the chassis out, which will be sooner than later, it needs a cap job.
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Re: Traynor YBA-3 Custom Special

Postby JC103 on Fri Jul 08, 2016 4:13 am

Hammond part number for the PT: 79691
Hammond part number for the OT: 79692
Traynor part number for the OT: A1332
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Re: Traynor YBA-3 Custom Special

Postby pbman on Fri Aug 19, 2016 11:29 pm

Hala Freakin Luya, I found this site and topic. I've been working on my YBA-3a for a while now and I too want to convert away from only using a 8 ohms. Plus, for me , I'm not that happy that the speaker connections are in series. I want a distinct 4 or 8 ohm connection. Some one told me that this this A1332 AKA 79692 has a hidden green ( 4 ohm) tap. They were wrong. There isn't any other speaker wires besides the yellow and black.

So here's my question:

What are the specs of this one in order to find a 4/8 tapped tranny? FYI, I'm using KT-120's in this bear and the amp isn't complaining. There's a mod out there to install 5- 1K- 5w resistors for each tubes, that's been done.

Thanks for you a help!
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