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Traynor YBA300

#141
Based on a 25 watt dissipation on a El-34, they had to use 12 tubes to get 300 watts, with the 6L6GC it's about 17/18 watts in a push-pull configuration I wonder what the plate voltages are in that amp? ... the old YBA1A running 90 watts on a pair of EL-34's was running on some high plate voltages 525/539 volts ...
 
#143
I find it interesting that Traynor included a "resonance" switch to help control speaker over-excursion (since tube amp output transformers don't have nearly the same damping factor as solid state power amps). Here is an excerpt from their owner's manual for the YBA300:

5. Resonance Switch
The Resonance switch is placed in the output stage of the power amplifier and controls the amount of low frequency damping. Pushing in the switch reduces the damping factor and allows the resonance of the speaker cabinet to be more pronounced.
Tip: Having the switch out will increase the damping factor and produce a tighter sound.

Kudos to Traynor! If this amp ends up having desirable tone, and if this amp can put out the power without distorting too early (which was the YBA200's downfall......under-trannied), they just might have a real winner on their hands!
 
#144
jastacey said:
Based on a 25 watt dissipation on a El-34, they had to use 12 tubes to get 300 watts, with the 6L6GC it's about 17/18 watts in a push-pull configuration I wonder what the plate voltages are in that amp? ... the old YBA1A running 90 watts on a pair of EL-34's was running on some high plate voltages 525/539 volts ...
Click to expand...
likely 7-800 volts actually
http://en.wikipedia.org/wiki/EL34
 
#145
Interesting read, though I don't like this part:

The EL34 was widely used in higher-powered audio amplifiers of the 1960s and 1970s, such as the very popular Dynaco Stereo 70 and the Leak TL25(mono) and Stereo 60, and is also widely used in high-end guitar amplifiers because it is characterized by greater distortion (considered desirable in this application) at lower power than other octal tubes[citation needed] such as 6L6, KT88 or 6550.
 
#147
Cool looking amp...I like some of the innovative features. Individual pair biasing means you won't have to buy a matched "12-tet" when you need to replace those EL34s...you can get away with buying "just" six pairs. :)

I'm with the group that would prefer 6550s, but who knows--until we hear it, it'll be hard to tell how the EL34s work in this application...
 
#156
I am pretty hyped about this new head. I have not heard it yet. I read through most of the postings and then did some investigative work. Let me know what you think.

The comment on YBA200 transformers may be a bit off-base - there never was a YBA200 transformer problem in fact Traynor has never had to replace one and neither has a dealer.

The early YBA200 bias circuit issue was due to bum 6550s, not auto-bias - It was omitted from the YBA200-2 mostly to skirt the early controversy and also because switching to pre-tested and matched Ruby KT88s made it redundant.

Traynor learned from the early YBA200 issues.

The YBA300 tells you when there's a bad tube and eliminates it from the circuit in such a manner that the amp keeps working. You also get a bias trim pot plus low, high & bad LED indicators for each pair of EL34s. The back panel will be as much fun to watch as the front one. You can even mix pairs of 6L6/5881s with the EL34s which is handy if you're on the road with dead tubes and the local shop doesn't have EL34s or 6CA7s. The tubes are cooled by top & bottom vents in the cabinet that create a passive chimney effect. In the year or so that Traynor has been testing the YBA300, tubes have lasted as long as you can expect, tube quality being what it is these days.
 
#160
Konan888 said:
I am pretty hyped about this new head. I have not heard it yet. I read through most of the postings and then did some investigative work. Let me know what you think.

The comment on YBA200 transformers may be a bit off-base - there never was a YBA200 transformer problem in fact Traynor has never had to replace one and neither has a dealer.

The early YBA200 bias circuit issue was due to bum 6550s, not auto-bias - It was omitted from the YBA200-2 mostly to skirt the early controversy and also because switching to pre-tested and matched Ruby KT88s made it redundant.

Traynor learned from the early YBA200 issues.

The YBA300 tells you when there's a bad tube and eliminates it from the circuit in such a manner that the amp keeps working. You also get a bias trim pot plus low, high & bad LED indicators for each pair of EL34s. The back panel will be as much fun to watch as the front one. You can even mix pairs of 6L6/5881s with the EL34s which is handy if you're on the road with dead tubes and the local shop doesn't have EL34s or 6CA7s. The tubes are cooled by top & bottom vents in the cabinet that create a passive chimney effect. In the year or so that Traynor has been testing the YBA300, tubes have lasted as long as you can expect, tube quality being what it is these days.
Click to expand...

This really helps to clear up the confusion on the YBA200's. Thanks for this!

I had been following this topic religiously because I've been in the market for a tube head. Dropped by long and mcquade the other day and got a killer deal on a used YBA200. I ended up going for it and I'm in the middle of having it checked up by Yorkville and retubing.

Really when you look at the issues that have plagued the YBA200, much of it seems to come down to quality issues with tube manufacturers. I think the advances with the YBA300 help to reduce the problems that poor quality tubes can bring about. That being said though, I think there's enormous potential with the now very affordable YBA200's and matching them with high quality, matched tubes.
 

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