Yamaha BX-1's - oh yeah!

[Mark B]

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.

 

[cdfac]

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!

 

[Mark B]

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?

 

[avionic]

Hey.Ive seen that amp somewhere before..:scratch2: How do you like those "James Audio" binding posts..

 

[SoCal Sam]

Are those VFET's?

 

[avionic]

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..

 

[Mark B]

Hey.Ive seen that amp somewhere before..:scratch2: How do you like those "James Audio" binding posts..

Pretty darn nice! I believe they can accomodate 4 gauge wire.

 

[whoaru99]

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 B]

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?

a cold beer would be nice....

 

[whoaru99]

Agreed!

 

[avionic]

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 B]

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?

 

[avionic]

http://www.audiokarma.org/forums/showpost.php?p=3244001&postcount=1
http://www.audiokarma.org/forums/showpost.php?p=3244174&postcount=5
http://www.audiokarma.org/forums/showpost.php?p=3245080&postcount=16
Currently have Chris's 5002 partially disassembled. Are these amps suppost to be 2 ohm stable?

 

[whoaru99]

If they are, you should ensure they exceed specifications by testing at 1 ohm.

Chris, you don't mind, eh?

 

[Mark B]

http://www.audiokarma.org/forums/showpost.php?p=3244001&postcount=1
http://www.audiokarma.org/forums/showpost.php?p=3244174&postcount=5
http://www.audiokarma.org/forums/showpost.php?p=3245080&postcount=16
Currently have Chris's 5002 partially disassembled. Are these amps suppost to be 2 ohm stable?

I used my PC5002M to drive the woofers on my IRS Gammas in extended mode. That is a < 2 ohms load.

 

[Mark B]

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

 

[avionic]

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

I'm rather familiar with this amp. Hardware wise
http://www.audiokarma.org/forums/showpost.php?p=3008407&postcount=1

 

[SoCal Sam]

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.

 

[MX117.MC7150]

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.

 

[cdfac]

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!