ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

Re: location for relay transformer? (help)...


 
2/26/2005 12:09 PM
MBSetzer
email
Re: location for relay transformer? (help)...
It's probably best to put it over by the main PT, along with its rectifier and main filter caps.  
 
Then run the DC supply lines over to the relay or relay board, where you have an additional cap for further filtering and anti-pop service.  
 
That way you can have fairly long unshielded relay power leads and run them just about anywhere, and any stray signals picked up by the relay power lines will have that interference quenched by the caps at either end.  
 
Otherwise with just a cap at the rectifier end, the wire leading away from there can act as an antenna and you get signal reception which can be audibly really bad if the coil inside the relay transmits this *insignificant* isolated power line interference to an open high-gain input terminal a few millimeters away.  
 
If a relay board is designed to run on an AC source, then I would suggest twisting the supply wires from the relay transformer over to the relay board rectifiers. Like other AC supply lines inside the chassis you need to be careful not to run them too close to hum-sensitive areas.  
 
Mike
 
2/26/2005 2:07 PM
Ian Anderson
email

Thanks for the replies everyone, just thought I'd mention what I'll be switching since most people assume it's a clean/dirty thing.  
 
I'm just having one (very) dirty channel but with an additional louder 'channel' whereby an extra gain and master volume pot are switched into circuit.  
 
... Ian
 
 
  Tuesday
Book Of The Day The Ultimate Tone, Volume III by Kevin O'Connor
Have you ever wondered if there is a better way to build a Bassman, Champ, Plexi, an 800, AC-30, Bulldog or Portaflex? Or you wanted to build an SVT with off-the-shelf parts? How about a master-volume amp that doesn’t change tone with the master setting? Everything you need to know is right here, including: proper grounding techniques, wiring methods, and mechanical considerations. Eighteen chapters cover the “iconic” amps everyone knows and loves, with schematics and layouts for each, along with the technical history of the product. Eyelet-board and chassis-mounted tube socket construction is used throughout, for easy servicing and modding. TUT3 is very accessible even if you cannot fully read a schematic and is a "must have" if you are going to build an amp for your self.

Note: The Ampage Archive is an Amazon Associate site. A small commission is paid to the site owner on any qualified purchase made after clicking an associate link such as the one above.
 
2/26/2005 2:14 PM
Ian Anderson
email

Also, I've got a small transformer with two seperate 12v taps to run the relays off since most of the threads I've read here seem to end up suggesting that this is the best way to go.  
 
... Ian :)
 
2/26/2005 4:50 PM
Ian Anderson
email
question for Gary (aka Glasman)...
Gary, what purpose does the 5.1v zener serve on that switching schematic you posted?  
 
... Ian :)
 
2/26/2005 8:24 PM
Gary (aka Glasman)
email

When i first build the amp, I didn't give a lot of consideration to driving the relays. The DC supply I ended up with put out about 18 volts so in lieu of using a voltage regulator, I dropped the excess voltage with a zener on the ground side of the relay. Those components are actually located in the footswitch.  
 
My latest amps use a voltage regulator (12v) to drive the relays. A little cleaner.  
 
Gary
 
2/27/2005 2:16 PM
Ian Anderson
email

Cheers Gary, I won't need the zener in that case since I have the 12v supply that the relays require.  
 
... Ian
 
2/28/2005 3:03 AM
Dave H
email

Hi Ian, are they DC relays? If you rectify and filter the 12V AC from the transformer it’s going to generate more than 12V DC so you may need to use some zeners.  
 
Dave
 
<<First Page<Prev Page 2 of 3 Next> Last Page>>