PSU for an old analog multifx rack unit

Hey guys,

I've got an 80's German made Nobels SST-19 rackmount guitar preamp/multifx, but unfortunately without PSU, and the power requirements are a bit unusual. It've got another fx box from the same manufacturer and it sounds great, so would like to put this rackmount unit to use again too!

The manufacturer's page says:

AC: 2 x 6,6 Volt 1A. (XLR Plug: Pin 1 (Middlecontact) = GND, 2 and 3 is AC. Please note: AC NOT DC!

http://www.nobels.com/schematics/nobels_sst19_sm.pdf

Anyone know if I can buy a PSU replacement ready made (can solder the XLR) - or alternatively is it difficult to build? I'm guessing I'd need some housing, a transformer and a fuse, but have no idea what to search for. I'm in the UK so a link to a suitable part in a UK/European electronics shop would be awesome!

Many thanks

Hi,

any 2x6 or 7V transformer rated at 20-30VA will be OK, IMO.

for example:

http://uk.farnell.com/multicomp/mcfe030-06/transformer-30va-2-x-6v/dp/9531700

Regards,
Milan

PSU has got 7806 and 7906.  7V secondary is not a standard item but 2 x 8V will do without any problem. PM me to remind and I'll have a look tomorrow. I am sure I have something which you can take for free. Just pay for the postage.

sahib said:

PSU has got 7806 and 7906. 

Click to expand...

and voltage doubler in front ...

http://www.eg.bucknell.edu/~ee222/lab5/group05/

why ruin your signal with all those opamps?

Sahib - thank you sir, very kind of you - PM sent!

CJ - you mean why would I ruin the guitar signal with the opamps? I'm really after the analog chorus and BBD stereo delay in this unit for studio use and would probably bypass the preamp!

moamps said:

sahib said:

PSU has got 7806 and 7906. 

Click to expand...

and voltage doubler in front ...

http://www.eg.bucknell.edu/~ee222/lab5/group05/

Click to expand...

Never looked at that side but yes there is. Thank you for the link. I did not know what a voltage doubler was.

However, I don't understand why would one specify a 6.6VAC secondary, double it to 13.2 and then regulate it back to 6.6VDC.

sahib said:

However, I don't understand why would one specify a 6.6VAC secondary, double it to 13.2 and then regulate it back to 6.6VDC.

Click to expand...

That is a nice piece of engineering.
(Hi needs also 5V for the digital part which draws more current than the analog part).

Regards,
Milan

I must be missing something.

What is the problem with getting 5V out of 6.6V?

sahib said:

I must be missing something.

What is the problem with getting 5V out of 6.6V?

Click to expand...

That's a good question.

-a

I am so crap at jokes that my attempt of sarcasm has gone unnoticed.

They probably had plenty of 6.6V secondary transformers left over from other digital designs. So the simplest solution would be to double it up to make up for the voltage drop required for 6VDC and 6.6VDC.