Elektor's "Ulti Amp" - Page 6

Piersma · 11th December 2020, 03:09 PM

Ebay offers some nice original (old stock) matched transistors.
I have used and experimented with different duals in the Ulti Amp.
The 2N2920 works fine, just as others..

Tailgunner · 11th December 2020, 03:55 PM

Quote:

Originally Posted by Piersma

Ebay offers some nice original (old stock) matched transistors.
I have used and experimented with different duals in the Ulti Amp.
The 2N2920 works fine, just as others..

Thanks for the tip, that will settle it as a replacement for the 2N2914.
What would be your favorite replacement for the BFX36 (preferably NOS).

Piersma · 12th December 2020, 11:11 AM

That would be the 2N3806

Tailgunner · 27th March 2021, 11:09 PM

I have had a look at the component layout (p.74 -elektuur 12/92) and it looks to me that diode D8 has the wrong orientation. On the layout there is a trace that runs from the anode of D8 to pin 2 of IC3. I think the trace should run from the cathode of D8 to pin 2 of IC3 according to the schematic.

Piersma · 29th March 2021, 06:07 PM

Part numbers of D7 and D8 are swapped on the silkscreen printed in Elektor february 1994.

Tailgunner · 29th March 2021, 11:11 PM

Are there other mishaps in the final PCB/schematic. I tried to look up a 'lek van elektuur' voor this amplifier but I came out empty handed.

Piersma · 30th March 2021, 12:21 PM

Not that I am aware off.

The best thing to do would be a redesign of the original PCB.

Tailgunner · 2nd April 2021, 09:59 PM

Quote:

Originally Posted by Piersma

Some more pics......

Could you send a large image of this photo?
What kind of fuses did you use. The 6.3 amp car fuses are unobtainable.

29th March 2021, 06:07 PM	#55
Piersma diyAudio Member Join Date: Jan 2003 Location: Netherlands	Swapped Part numbers of D7 and D8 are swapped on the silkscreen printed in Elektor february 1994.

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11th December 2020, 03:09 PM	#51
Piersma diyAudio Member Join Date: Jan 2003 Location: Netherlands	Ebay offers some nice original (old stock) matched transistors. I have used and experimented with different duals in the Ulti Amp. The 2N2920 works fine, just as others..

12th December 2020, 11:11 AM	#53
Piersma diyAudio Member Join Date: Jan 2003 Location: Netherlands	That would be the 2N3806

27th March 2021, 11:09 PM	#54
Tailgunner diyAudio Member Join Date: Jan 2019	I have had a look at the component layout (p.74 -elektuur 12/92) and it looks to me that diode D8 has the wrong orientation. On the layout there is a trace that runs from the anode of D8 to pin 2 of IC3. I think the trace should run from the cathode of D8 to pin 2 of IC3 according to the schematic.

29th March 2021, 11:11 PM	#56
Tailgunner diyAudio Member Join Date: Jan 2019	Are there other mishaps in the final PCB/schematic. I tried to look up a 'lek van elektuur' voor this amplifier but I came out empty handed.

30th March 2021, 12:21 PM	#57
Piersma diyAudio Member Join Date: Jan 2003 Location: Netherlands	Not that I am aware off. The best thing to do would be a redesign of the original PCB.