Retro Amp 50W Single Supply

[Joel Wesseling]

I think you can use PSU 15R or PSU 10R. I posted a layout for these in Apex 100W threre.

I ordered boards and working on CRC. Many Thanks!

Single rail 10R sounds great to me! Does it look like TO-3's are sticking around for the near and distant future?

 

[prasi]

For the compact crc, if you plan on using it on high power, best to use chassis mount rectifiers and connect it to pcb via wires.

PSU 10R , I will ditch them and use on-semi to-264.

PS: I seem to have the exact layout.

 

[apexaudio]

I ordered boards and working on CRC. Many Thanks!

Single rail 10R sounds great to me! Does it look like TO-3's are sticking around for the near and distant future?

There is single rail PSU10R and PSU15.
Retro Amp 50W Single Supply

 

[Joel Wesseling]

Thank You, Prasi. Thank You, Apex.

"For the compact crc, if you plan on using it on high power, best to use chassis mount rectifiers and connect it to pcb via wires."

My plan for one A40 stereo Amp is one CRC-PSU for each channel with one dual winding Trafo to each supply, two 25A bridge rectifiers per channel.. Should be safe, heat wise, for 4-SIP case, I believe - If not please let me know?

The boards are mounted in a Holed base plate so theres not much available heat sinking..

 

[prasi]

even base hole plate is enough to dissipate heat if you use heat sink paste and isolation material.
but in your case, if you use it for regular home listening, you would be safe with sip rectifiers.
don't use at high volumes at home parties or disco with lots of bass. i hope i am clear...
I have blown 8 TO-220 rectifiers at home on a single channel HT subwoofer , at not too loud listening ... but subs require a lot of power.
PS to others: I have a design for Sansui F 2624 driver board ( as per Sansui Vintage Amplifier Resurrection, Creating a Modern F2624 Replacement – Toli's DIY), if anyone is interested, I am selling gerbers…
I saw an an e-bay listing somewhere for very high cost for a pair of boards.... that's daylight robbery!

 

[Joel Wesseling]

Clear on that, no loud disco or real high volumes with low bass! Need to preserve the hearing that I have left.

The AX-6 retro amps are doing an amazing Job with the Kick Drum and bass guitar on Patricia Barber's "Regular Pleasures" at a comfortably high volume on an F3=42hz ported speaker.. A40, cant wait to hear It!

 

[tiefbassuebertr]

I'm busy doing a board for this

anywhere was described in detail, why R12 (39R) in this circuit is important to get a more stable idle (quiescent) current through the output stage.
Who know, which paper it was ?
Thanks for an advice.

 

[Joel Wesseling]

MJL4281 is cheap, but On competes with themselves with MJL3281, MJW4281, MJW3281, NJL4281, NJL3281. there is also MJL21194 and MJW21196. I used white box MJ15003 since I had a heat sink drilled for TO3, sold as NTE181MP.

Thanks! MJL4281 is backordered but wait time is not really a problem. But, curious about MJW3281 at half the price and available now.

 

[prasi]

I think you will be happy with MJL21194 , as its to-264 and slower hence suited to retro type amps. bigger the package , longer the life

 

[junior35]

@joel wesseling
PM sent

 

[indianajo]

MJW3281 has less Vceo than MJL4281, 230 versus 350. MJW3281 has a little less guaranteed gain than MJL4281, 50 instead of 80. Neither should matter for an output transistors running at 70 v rail. Original TO3 transistors (40636) for similar circuits had Vceo of 60? & gain of 5, which was marginal. Short lives and sound inferior to vacuum tubes (6CA7) in 1966. Main sound inhibitor in 1966 was Ft of 400 khz, versus 4 mhz for epitaxial transistors.

 

[fazildiken]

Ok here's the corrected 10uF polarity ver.1.6 using 25mm caps.
Regards,

I want to have the apex ax6 pcb done. But I can't find the gerber file anywhere. Can you help me.

 

[prasi]

this and the quoted post theirin give all necessary files
Retro Amp 50W Single Supply

 

[AdeS]

Retro Amp 50W Single Supply. Rev1, I don' know if this is latest.

 

[fazildiken]

hello x, thanks, we are not doing too bad... under complete lockdown.

Here are the gerbers for the apex ax-6 single supply amp. yes, i designed it for to-247/264 type output devices. I think i have spare pcbs but no shipping in sight...
the above quoted post gives the schema , pcb, stuffing and bom.

Take care of yourself...
regards
prasi

Thanks Prası. However I am interested in the 2n3773 transistor version.

 

[prasi]

Here is a quick draw, if interested I will post gerbers.

 

[fazildiken]

Thank you very much prasi. Thanks for your effort. I would appreciate it if you post a gerber file.

 

[prasi]

Here you go, mind you you can go for diy home pcb etching if you feel up to it.

 

[LKA]

Tuned retro amp (AX6 alike) measurements. Single supply, 75W/4R, class-b, no emitter resistors.

 

[gannaji]

Dear LKA,
Kindly open a new thread and post details about both the above amps.
--gannaji