Sony HA-55 Head Amplifier

[freebee]

I've just bought a Sony HA-55 phono head amp, and there's a problem with the left channel. Somehow the bass is missing and I'm wondering what can cause that in a head amp (there might also be a minor volume difference).

I've got the schematics (and parts list) so I can test if all components are working according to specifications.

Would appreciate however if somebody could point me in the right direction of where to start.

Thanks!

[kevinkr]

I would assume given that it is over 30yrs old it is due for full electrolytic cap replacement at minimum..

http://www.thevintageknob.org/SONY/s...HA55/HA55.html

http://translate.google.com/translat...%26prmd%3Divns

[nac134]

I second that. Also, it might be a good idea to post the schematic here if you're going to get into it. The quality of advice that can be given rises exponentially once there's a schematic.

[freebee]

Any idea how I can upload a PDF file? (schematics)

[freebee]

Thanks for the Japanese link Kevin. Great stuff this guy has.

[Mooly]

Originally Posted by freebee

Any idea how I can upload a PDF file? (schematics)

Or take a screen of the pdf like this and post as a .jpg

[kevinkr]

Depending on the size of the pdfs you can just attach them using the "manage attachments" button under advanced editing. I replied to your PM just a little while ago..

[kevinkr]

Hi Orson,
Check your email for my response. I believe a cap replacement as stated is in order. Specifics are in my email response.

Good Luck!

[freebee]

Hi Kevin,

Thanks for your advice. Will try to find the right values to replace the Tantalums as well as the Electrolytes.

Kind regards,
Orson