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Bryston tiny transformers in amp.!

T

tlxaudio

New Member
I opened my newly purchased second hand Bryston 2B LP (pro?) and I measured the size of the transformers in order to replace them with 230V parts (for Europe) assuming I can find them some somewhwere!
They look really small and based, on their dimensions, they should not be able to deliver more than 100 VA when Bryston indicates 720 VA consumption at the rear of the amplifier! The amp is supposed to deliver 100W per channel on 4 ohms load!
For this size (8 cm x 3.5 cm) I only could find 2 x 30V - 80 VA transformers!
Any input will be very useful for me. Thanks!
 

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Most probably their power "rating"is according FTC rules, which is not power rating a tech would consider RMS power rating.

As the Bryston schematics indicate, the transformers itself are rated 100 Watts, which means that you would need a 100% efficient amp circuit to get 100 Watts RMS output. So the 4 Ohms figure will probably not be met when putting on a sine wave and steer it to max. Probably it will meet 8 ohms power with no problem.
 
Even if Bryston is a 'reputable firm' I have never seen so small transformers in a supposed 60W/8 ohms -100W/4 Ohms amplifier. (they indicate 720 Va at the back of the amplifier!)
Anyway, regarding Xformers replacement I have been quoted 700 USD (equiv.) by official dealers In France and just a bit less in Switzerland were I live.
Bryston Canada never answered my request!
 
The Bryston schematic shows a 56V 100VA transformer - one for each channel. As long as the transformers you replace them with match the output of the originals you should have no issues. Also note the cap across the power switch for 220V use.
 

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tlxaudio said:
Even if Bryston is a 'reputable firm' I have never seen so small transformers in a supposed 60W/8 ohms -100W/4 Ohms amplifier. (they indicate 720 Va at the back of the amplifier!)
Anyway, regarding Xformers replacement I have been quoted 700 USD (equiv.) by official dealers In France and just a bit less in Switzerland were I live.
Bryston Canada never answered my request!
Click to expand...

Any evidence aside from a visual "test" that shows the unit does not generally meet published output specs?
 
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kyle said:
The Bryston schematic shows a 56V 100VA transformer - one for each channel. As long as the transformers you replace them with match the output of the originals you should have no issues. Also note the cap across the power switch for 220V use.
Click to expand...

That's the problem. He feels they're too small. But, they are sized to support the specs/design goal of the amp. And given Bryston's rep, I fully expect the amp performs to specification.
 
I've used Toroidal transformers in amp builds. I just ordered another. The physical sizes were smaller than the standard steel core transformers with the same specs. I've come to like them. You can stack them and mounting is in many cases easier. I haven't tried using toroidal output transformers that seem to be all the rage on the other side of the pond yet though.
 
whoaru99 said:
That's the problem. He feels they're too small. But, they are sized to support the specs/design goal of the amp. And given Bryston's rep, I fully expect the amp performs to specification.
Click to expand...
Yes, I read that. I added the schematic so that it wasn't guess work done by eyeballing the size of the trannies. There's one per channel so the size looks right and the schematic confirms that.
Bryston has a great durability reputation and I would trust their design to last above almost any other manufacturer particularly with a design that has been around as long as the 2B LP has.
 
I agree! I will probably use a 230-110 V step down toroidal transformer in a separate enclosure . What the power rating should be?
 
Given the unit contains two 100VA transformers, is there any reason to think the stepdown would need to be appreciably larger? Say perhaps something like 300VA for good measure/cushion?
 
whoaru99 said:
Given the unit contains two 100VA transformers, is there any reason to think the stepdown would need to be appreciably larger? Say perhaps something like 300VA for good measure/cushion?
Click to expand...

I’d guess that’s a good number. OP can price them out and see what the cost is starting in the 300VA range. I’m running a 1500VA step down for my Japanese gear but only because I ran into a few for a steal.
 
I guess resale value will go up if voltage input is right for the area, instead of down. I would never buy a used 110V unit in my area for resale as the possible buyer would need a transformer, which keeps away 95% of people possible interested in buying one.

And there is another thing, why buy an amp considering resale value?

If loudspeakers are 8 ohms, an 80W transformer will do, I guess. In the end, a 300W step-up transformer will have its losses added up in the chain, also, if choosing a not-very-oversized input transformer. Myself I would not hesitate to put in 80 watts transformers but probably right size 100W should be somewhere
around. Btw I have an old 4b and afaik the transformer brand is Plitron
 
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