Aleph 30 gain

[Freddie]

I just did some measurements on my Aleph 30 amplifier.
In the service manual, it says that the gain in single ended mode is 26dB. However in my amp the gain is only about 10 (20dB).
Is there something wrong with my amplifier? I did ground the -input, but I didn't have any speaker or resistor coupled to the output of the amplifier. And I don't have R8 or R1 installed in the circuit.

Isn't the gain of the amp (in SE-mode), reffering to the schematic, set by R7, and R3 in parallel with R6. About 21,92dB?

The service manual can be found here.

www.volksamp.com/downloads/a30manr0.pdf

regards
/Freddie

 

[GRollins]

The numbers are backwards. Using a balanced input gives you a "free" extra 6 dB of gain.

Grey

 

[Freddie]

Ok.. nice

Then I'll guess everything is just fine with my amp then!
Nothing runs too hot either.. Heatsink temperature about 50 degrees C.

Thanks for the reply
😀

 

[Freddie]

Just wanted you to know..

Grey,

I'm using your PCB layout for the front end. It works great!
Thanks for publishing it on diyaudio.com

/Freddie

 

[Nelson Pass]

You have to short XLR pins 1 to 3 to get the extra gain
on RCA input, but then that figure will be 20 dB

 

[GRollins]

Nelson did the hard part. All I did was scratch a few lines on a piece of paper one night.

Grey

 

[Freddie]

Yes.. I know, Nelson did the hard part.

Thank you Nelson Pass for supporting the DIY community!🙂

 

[gema]

Hi guys,

Where i can find Grey's PCB for Aleph30?

Thanks and Regards

Matjaz from Slovenia (Europe)

 

[HarryHaller]

PCB

psssst..... Don't tell anybody I told you but you can use the search feature. It seems to be a closely guared secret for some reason. I like the panos PCB. Remember, mums the word.... they get real upset about search suggestions, and we try to mantain harmony here at all cost.

http://www.diyaudio.com/forums/sear...id=21708&sortby=lastpost&sortorder=descending

 

[GRollins]

By now there are probably a dozen different layouts floating around. The layout I did was originally for an Aleph 2 with some of the features of the Volksamp 60. I don't remember exactly, but I think I called the thread "Aleph 2 (and others) as a project." Someone asked if the layout would work for other Alephs--I believe the consensus was yes.
Use any layout that makes you happy. I'm listening to four copies (i.e. two pairs of monoblocks) of those boards even as we speak. Sonny Rollins (no, we're not related) on now. Next up: Max Roach.

Grey