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Hoffman Amps Forum image Author Topic: Installing a Belton Digilog in a tube amp - Power supply issues  (Read 3600 times)

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Offline LooseChange

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Installing a Belton Digilog in a tube amp - Power supply issues
« on: September 27, 2010, 12:35:25 pm »
I'm trying to install a Belton digital reverb unit in a small tube amp and I am having hum issues with the power supply.  I setup a voltage doubler sourced from the heater supply and then regulated to 5 volts with a 7505 regulator chip.  I used two 1000uf caps and adding uf does nothing. I have also tried many grounding schemes and nothing seems to help. Disconnecting the audio lines and keeping the power source connected still makes hum. I would call the hum a buzz at 120hz.
Any ideas?
Thanks!
Call me Dan
www.fydamps.com

Offline bibi

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Re: Installing a Belton Digilog in a tube amp - Power supply issues
« Reply #1 on: September 27, 2010, 01:11:03 pm »
Why would you use a voltage doubler which is just asking for more noise?  6.3vac rectified will get you around 8.5 anyhow which is more than enough for a 7505. 
That said, I just used a second transformer that I had laying around for the power supply.  It's a nice reverb for sure but they can get really noisy at the higher output.
Which circuit are you using?  I didn't like the one that is floating around the web at all-- to me it sounded better using an adaptation of the traditional Fender style circuit.

Offline PRR

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Re: Installing a Belton Digilog in a tube amp - Power supply issues
« Reply #2 on: September 27, 2010, 06:28:35 pm »
> voltage doubler sourced from the heater supply

The devil is in the details.

Draw us a picture.

Or get a 4-pack of D-cells or a 6V lantern battery, power the Belton off that just to try.

Offline LooseChange

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Re: Installing a Belton Digilog in a tube amp - Power supply issues
« Reply #3 on: September 27, 2010, 07:01:37 pm »
I found a small 5v transformer and hooked it up... Quiet as can be.
The reverb does not sound too bad.
The regulator is a 7805 (wrong above)
Call me Dan
www.fydamps.com

 


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