Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Oddvar on February 19, 2019, 09:30:42 am

Title: Question Bandmaster part
Post by: Oddvar on February 19, 2019, 09:30:42 am

Hi.  I am wondering what part this is, is it a K1104 Raysistor Opto Isolator?  -If not, any Ideas?

Title: Re: Question Bandmaster part
Post by: sluckey on February 19, 2019, 10:13:51 am

It's a Fender style tremolo optoisolator. It's just a NE-2 lamp bulb and a photocell in some shrink tubing. The lamp flashes at the tremolo speed and causes the photocell resistance to change at the tremolo speed. Fifth item down on this page...

https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Lamps&ORDER_ID=!ORDERID!
 (https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Lamps&ORDER_ID=!ORDERID!)

Title: Re: Question Bandmaster part
Post by: Oddvar on February 19, 2019, 10:21:50 am

Thanks again Sluckey, could you recommend a OT for the bandmaster fro Hoffman also?

Title: Re: Question Bandmaster part
Post by: sluckey on February 19, 2019, 10:32:23 am

I would use this one...

Heyboer Output for Bassman-Super Reverb. Part number Mojo774.

https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Transformers&ORDER_ID=!ORDERID! (https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Transformers&ORDER_ID=!ORDERID!)

Title: Re: Question Bandmaster part
Post by: Oddvar on February 28, 2019, 07:37:10 am

Bought the tremolo opto isolator from Hoffman.  Are they directional?  I see others has a mark what way should be closest to the tube sockets?

Title: Re: Question Bandmaster part
Post by: sluckey on February 28, 2019, 09:14:11 am

Yes. Hoffman's description tells you which end is which.