[mulveling]

Quote:

Originally Posted by Elizabeth /img/forum/go_quote.gif Whoo HOO I DO have the mysterious knob in the back (it does seem to vary the power to the tubes) I switched to 6SN7s and the output tube you suggested (the 2C51/adapter came with the amp) Too bad the seller sent me a huge pile of 6BL7s I had to steal a pair of 6SN7s from a buffer.

Sometimes an unmarked 2-setting knob is used to switch inputs, other times it is the notorious "high voltage" switch. If it's the latter then usually you want to rotate it the more counter-clockwise position (relative to as when you're facing it directly) for the lower voltage setting (< 300V). You NEVER want to turn such a knob while the amp is on, especially to the higher voltage setting! My tech measured the high voltage setting at 500V+ to the output tube plates, on my old SDS. That was NOT acceptable!

Also, the high voltage setting is too much plate voltage for a 6sn7 (OK for the 6BL7 plates, though who knows about the rating of the caps inside, or whether the 6BL7 heater current draw is OK for the transformer, etc). This voltage setting only affects the two output tubes, not the gain tube (and the position of the input tube on Singlepower amps is not always entirely consistent either). Keep the knob it on the probable "low" setting until you find out more about that particular amp. Mikhail wasn't known for following any kind of standards on any given day.

Again, good luck and hope you can enjoy the music in "relative" safety

My old Singlepower SDS and Headamp Gilmore Reference are the two headphone amps I'll miss the most. Though, now I have a pair of Rogue Apollos to drive my Tannoy Kensingtons and keep me toasty warm at night

 

[Elizabeth]

I am certain the knob is a voltage device. I did 'play' with it. That's how I decided it must control votage to the heaters.
I still have to say after reading and seeing pictures of other folks interiors, mine is beautiful. the layout, the wiring.. it looks like a real professional made it. Some of the pictures of other folks Singlepower stuff they look like a mess!
My main interest is the transformer. The seller said it has the Supra transformer.??? So is that enough? and supposedly thousands in added cost mods. (though, to be honest, the ad says $4000. where i saw another ad that ad was copied from (entire ad-exact wording) except it was $400. in added mods. So I believe the mods are $400.
i actually have been listening for another hour or two, andI like the 6BL7s better. Though the ones I have in now are OK.
I know some about electrical stuff.. (not particularly tubes though)
I really have to say the response seems a bit hysterical. Everyone shelving a product because a few folks get excited. Then, none of these has actually blow up or started on fire? no. So i really just take this stuff with a BIG grain of salt. i mean giant caps exploding would be ALL OVER this site. none. no fires.. none.
I can say the interior of the unit that the dude who started the complaint IS crappy. It really looked like a twelve year old made it in there.
Well i'm a happy SinglePower MPX3 customer so far.

 

[Frihed89]

A lot of SP amps don't have what SP said they had inside them. Make sure it can deliver 6.3V DC to the filaments. Better yet, can you see what make / model power transformer it has.

The 6BL7s sound better to me (or no different) at low power -- 350 plate voltage--and with a nice neutralish 6SN7 (7N7 is great) or 6414-like input, if you have the 9-pin 12AX_ family adapter. The 6414 is like a 12AV7.

 

[Skylab]

The question with the 6BL7 in the MPX3 is can the transformer handle the 4.5 amp total current draw of 3 of these, versus the 1.8 amps that 3 6SN7's would draw...pretty big difference there.

 

[Feanor]

I have a 2004 Mpx3-6cg7, woo!

Seems like we all got burned. No problems with mine so far, I'll have to get a friend to take it apart.

 

[purk]

I have a 2001-2 Singlepower SDS, pretty much the first SDS ever made. Love it since day one, still the best sounding single end amplifier I've heard. Had some problems before but everything is good now.

 

[Elizabeth]

I started with three 6BL7's in the MPX3. Then switched to the 6SN7, and a small tube in an adaptor. I liked the sound of the 6BL7's better so i will go back to them. The previous owner clearly was using 6BL7's as he sent me a pile of at least 20 6BL7s... (I had to rob the 6SN7's from a buffer I have...)

 

[rosgr63]

Quote:

Originally Posted by purk /img/forum/go_quote.gif I have a 2001-2 Singlepower SDS, pretty much the first SDS ever made. Love it since day one, still the best sounding single end amplifier I've heard. Had some problems before but everything is good now.

What tubes are you using?

 

[purk]

Quote:

Originally Posted by rosgr63 /img/forum/go_quote.gif What tubes are you using?

I'm using two Raytheon 6BX7GTs as outputs and GE12AY7 as an input tube. Everything is depending on my mood actually, but I keep coming back to this combo using with the R10.

 

[Frihed89]

It is a bad idea to use the 6BL7 as the input tube. Use a 6Sn7, 7N7, 12Ay7, 6414, 7062, 12At7...something like.

 

[Happy Camper]

Bump for other SP owners who may not have seen this thread.

 

[MikoLayer]

does wayne at BC still accepts requests for amp check up / repair? I do have a ppx3 here that might need some attention..
no probs at all so far, but who knows.