Aksa Lender P-MOS Hybrid Aleph (ALPHA) Amplifier

[Kokanee]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)

 

[6L6]

X, is there a disadvantage to using two, one to each channel, and not running them in series?

The bricks are monopole (0-24v) and the amp needs a bipolar (-24 -0- +24V) PSU. You need to run them in series and call the connection point Ground, so that the amp sees a negative and positive voltage in respect to ground.

Ground is wherever we make it, cool trick, no?

 

[xrk971]

GB status update

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, Invoice sent
bk856er - 1 pair, Paid
Vunce - 2 pairs, Paid
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Paid
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair, Invoice sent
Kokanee - 2 pairs, Invoice sent

 

[zman01]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair

 

[Kokanee]

Hi X,

Received the invoice. Ordered 2 pairs, is that 4 pcb's, enough for 2 stereo units. Invoice should be 2 x $22 +$10 for shipping. Please send me a revised invoice if I am correct.

Myles

 

[bvtrinh]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair
Bvtrinh - 1 pair

 

[xrk971]

Hi X,

Received the invoice. Ordered 2 pairs, is that 4 pcb's, enough for 2 stereo units. Invoice should be 2 x $22 +$10 for shipping. Please send me a revised invoice if I am correct.

Myles

Sorry about that - revised invoice sent.

 

[GnuB]

The bricks are monopole (0-24v) and the amp needs a bipolar (-24 -0- +24V) PSU. You need to run them in series and call the connection point Ground, so that the amp sees a negative and positive voltage in respect to ground.

Ground is wherever we make it, cool trick, no?

That is slick; thanks for the explanation.

 

[mlloyd1]

Hugh:

Just curious - why no resistors in the diff amp emitters?

mlloyd1

 

[muthumuthiah]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair
Bvtrinh - 1 pair
muthumuthiah - 1 pair

 

[AKSA]

Hi Michael,

Thanks for your post, perceptive question.....
Notice the nested fb, 220k through 10nF. At 1KHz this is around 236k ohms.
This increases the interstage fb with higher frequency.
LTP degen reduces the loop gain and, significantly, the accuracy of the error signal; I am using nested fb here, but not throwing away the high transconductance with degen. The global fb at 1KHz is 236k/22k, a very low 10.73 which is only 20.6dB. All this follows the maxim that you linearise as much as you can, THEN add global feedback. Best to use nested fb to improve the linearity of 1st and 2nd stages and the drive of the VAS, rather than throw it away dealing with the error signal and maintaining a highish output impedance of the VAS.

HD

 

[markus22ch]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair
Bvtrinh - 1 pair
muthumuthiah - 1 pair
markus22ch - 1 pair

 

[schlomoff]

schlomoff:1 pair

 

[manniraj]

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair
Bvtrinh - 1 pair
muthumuthiah - 1 pair
markus22ch - 1 pair
manniraj - 2 pair

 

[xrk971]

Here is the latest update on the Big Boy from Hugh. The simulation approximates an FDA69N25 and IXTH48P20P devices with three parallel IRFP240/9240 devices. They have approximately triple the capacitance. This eliminates need for matching output devices and keeps CPU heatsinking simpler.

 

[BenY]

Here is the latest update on the Big Boy from Hugh. The simulation approximates an FDA69N25 and IXTH48P20P devices with three parallel IRFP240/9240 devices. They have approximately triple the capacitance. This eliminates need for matching output devices and keeps CPU heatsinking simpler.

Why so little current through T3..???

 

[Juntuin]

1 pair 20w, please!

Pinocchio - 1 pair, Invoice sent
6L6 - 1 pair, * Need PayPal address *
bk856er - 1 pair, Invoice sent
Vunce - 2 pairs, Invoice sent
Pcgab - 1 pair, Invoice sent
jwjarch - 1 pair, Invoice sent
vvs07 - 2 pairs, Invoice sent
jacques antoine - 1 pair, Invoice sent
GnuB - 1 pair
Kokanee - 2 pairs (ship to Canada address please)
zman01 - 1 pair
Bvtrinh - 1 pair
muthumuthiah - 1 pair
markus22ch - 1 pair
manniraj - 2 pair
Juntuin - 1 pair

 

[xrk971]

I am wondering if maybe we should be using a 40V trafo and then put it through the nice Prasi cap Mx board to drop to 36v dual rail. We get nice ripple free 36v and lots of amps without such a large capacitor.

http://www.diyaudio.com/forums/soli...sy-capacitance-multiplier-27.html#post5214663

Just some more IRFP's and maybe a pair of 22mF or 33mF caps and exrernal bridges.

 

[irribeo]

Wow Juntuin, your Guardian is nice!

 

[Vunce]

If we used a 40v transformer, wouldn’t the dc voltage after the cap Mx be around 50vdc?