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Yamaha BX-1's - oh yeah!

Mark B

Yamaha Fan
Subscriber
Made a cash and barter deal with AKer justrideit for his BX-1's. The first one arrived today, the other is at avionics behaving badly and driving Dave nuts.

Got this just in time for winter. It's a hell of a room heater.
 

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curious to hear what you think. if only we could mind-meld our two mono listening experiences together, we could have some idea of what they sound like in stereo!
 
curious to hear what you think. if only we could mind-meld our two mono listening experiences together, we could have some idea of what they sound like in stereo!
That's an idea. :scratch2: I trust that Dave will solve the problem with my other BX-1. What's the problem with yours?
 
Hey.Ive seen that amp somewhere before..:scratch2: How do you like those "James Audio" binding posts..
 
Real Class A goodness; play music, heat your room, and cook breakfast all at the same time. Besides the company of a good woman, what more could one want? ;)
 
Mark . I Just used those resistors to measure the output of a M-4 I have on the bench.. 156 wpc before clipping into 8 ohm.
 
Mark . I Just used those resistors to measure the output of a M-4 I have on the bench.. 156 wpc before clipping into 8 ohm.
Not bad! The M-4 is a heck of a little amp.

Any chance of testing a PC5002M into 2 ohms? :banana:
 
If they are, you should ensure they exceed specifications by testing at 1 ohm. ;)

Chris, you don't mind, eh?
 
If they are, you should ensure they exceed specifications by testing at 1 ohm. ;)

Chris, you don't mind, eh?
I do believe it is. The power supply is way overbuilt, so it doesn't run at the ragged edge of destruction.

2SC2608 NPN 200V, 17A, 200W, 150°C, 100µA, fT 20MHz SANKEN 10 per channel
2SA1117 PNP 200V, 17A, 200W, 150°C, 100µA, fT 20MHz SANKEN 10 per channel

that's 40 output transisters
 
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Nope,,2SC2565 and 2SA1095 six of each..
http://www.bdent.com/search/part.jsp?partnum=2SC2565
http://www.bdent.com/search/part.jsp?partnum=2SA1095

100 wpc "classA" into 4 or 8 ohm. Switch on front panel lowers the rail voltage for 4 ohm load.
Sam , you won't like'm cause they run to hot..But sound soo good..

Avionic, I make a distinction between hot running "consumer" grade Yamaha's and models that are built to a higher standard like the M-2, B-2, and presumably Mark B's BX-1's.

I'll give the BX-1 the benefit of the doubt. Looks like there is enough shielding inside and the boards and components are robust enough to take the heat. Hopefully, Yamaha spec'ed 105 degree caps.
 
Not only do they run too hot they are the 'brightest' sounding amps I've owned. Especially with metal dome drivers. IMHO they were under-designed from a heat dissipation (heatsink) standpoint. Should have a muffin fan built-in like their pro-amps. The Sony TA-N86B PLPS runs hot in Class A, but only the PLPS and is not as hot as BX-1. Might work best with a tube preamp that could help roll-off those highs. As always, YMMV.
 
Hopefully, Yamaha spec'ed 105 degree caps.

there are at least a few 85C caps, if not all of them.

Avionic, let's see what it does on the 4 Ohm load first before we think about trying a 2 Ohm load test. Not that I'm all that worried about it, but it's been away for me for TOO LONG (:tears:) and if something were to break, so would i!
 
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