I have the ones from post #2: http://www.diyaudio.com/forums/attachments/swap-meet/15569d1065019964-75-parts-sale-not-only-b2.jpg
I got the 600VA transformer in the mail yesterday, and I had time to get it installed today. I changed the rectifiers from MUR860's to some 50A chassis mount bridges because they were running really hot and there wasn't a very convenient way for me to sink them. I ended up with about .2v of voltage drop without a load connected to the PS compared to the MUR860's, 25v instead of 25.2.
I measured the rails with the amp boards connected and I have about 22.2v, lower than I expected, but it seems to be operating just fine, no more mechanical buzzing or excessive heat from the transformer so I'm happy.
And the sound is just fantastic, I don't like describing sound, but in my opinion, it easily beats a gainclone and is very smooth like a SET tube amp. Really makes my little Wharfedale Diamond 8.2's sound much bigger than they are. The amp feels a lot more powerful than the 25w on the spec sheet would suggest, I'm very pleased!
Listening to Rodrigo y Gabriela 11:11 on it right now.
A couple obligatory pics..
I measured the rails with the amp boards connected and I have about 22.2v, lower than I expected, but it seems to be operating just fine, no more mechanical buzzing or excessive heat from the transformer so I'm happy.
And the sound is just fantastic, I don't like describing sound, but in my opinion, it easily beats a gainclone and is very smooth like a SET tube amp. Really makes my little Wharfedale Diamond 8.2's sound much bigger than they are. The amp feels a lot more powerful than the 25w on the spec sheet would suggest, I'm very pleased!
Listening to Rodrigo y Gabriela 11:11 on it right now.A couple obligatory pics..
Attachments
They are 22000uF caps, do you think they might be a little small for 2 channels?
Thanks for the clarification. Didn't want to make a mistake. lol.
Still trying to find a PS schematic that I want to use.
James
I was kicking around that idea as well, I should have enough vertical room to stack them
Than,
So would the PS schematic listed on page 15 of http://www.firstwatt.com/downloads/f4_om.pdf be a goo fit for a mono X-J?
Speaking of whitch. Peter I know you have been busy with your phono stage but have you had time to test the X circut?
Also just throwing this out there, but there have been concerns that using 5 of these amps for my HT might cause issues in the room with ambiant heat. What do you all think?
So would the PS schematic listed on page 15 of http://www.firstwatt.com/downloads/f4_om.pdf be a goo fit for a mono X-J?
Speaking of whitch. Peter I know you have been busy with your phono stage but have you had time to test the X circut?
Also just throwing this out there, but there have been concerns that using 5 of these amps for my HT might cause issues in the room with ambiant heat. What do you all think?
I intend to use the attached scheme as my PS but would like to exclude the 1.8mH
Attachments
IRFP240's are such common parts, it's hard to imagine why
anybody would bother selling fakes. You can check them
by measuring Vgs, and see if they fall in the range of about
4.5 volts at 1 amp.
Thanks Mr. Pass, overdue appreciation. I will take it is as genuine parts.
I got the 600VA transformer in the mail yesterday, and I had time to get it installed today. I changed the rectifiers from MUR860's to some 50A chassis mount bridges because they were running really hot and there wasn't a very convenient way for me to sink them. I ended up with about .2v of voltage drop without a load connected to the PS compared to the MUR860's, 25v instead of 25.2.
I measured the rails with the amp boards connected and I have about 22.2v, lower than I expected, but it seems to be operating just fine, no more mechanical buzzing or excessive heat from the transformer so I'm happy.
And the sound is just fantastic, I don't like describing sound, but in my opinion, it easily beats a gainclone and is very smooth like a SET tube amp. Really makes my little Wharfedale Diamond 8.2's sound much bigger than they are. The amp feels a lot more powerful than the 25w on the spec sheet would suggest, I'm very pleased!
A couple obligatory pics..
Are those ebay heatsinks? How warm do they get?
Has anyone completed an Aleph J-X? Pics
That should be ok, but if it was me I would probably double the amount of capacitance.