Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: galaxiex on August 18, 2018, 03:40:30 pm

Title: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 18, 2018, 03:40:30 pm
Hi folks, I'm new here.

I recently converted my Blues Junior cream board version, to hand wired eyelet card with tube driven reverb.
Thought others might like to see it.

Thanks to Hoffman for all the great information available on the site.

Here's the completed project but still the wrong reverb tank in there.

Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 18, 2018, 03:42:34 pm
Here's the schematic.

I mish-mashed together the AB763 front end with the Blues Junior circuit from the Master vol to output.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: sluckey on August 18, 2018, 04:09:13 pm
Very nice!
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 18, 2018, 05:02:01 pm
Thanks!

I should mention this is my first amp build.
I've worked on, and tweaked, several tube and solid state amps, but never actually built one before this.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 19, 2018, 03:42:11 pm
Here's how I took care of the tube mounting issue, and of course,
cut another tube socket hole.

Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: MFowler on August 19, 2018, 09:21:45 pm
Beldon noval tube sockets fit fine in the stock BJ holes without need for board inside or new panel on outside.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 19, 2018, 10:52:50 pm
Beldon noval tube sockets fit fine in the stock BJ holes without need for board inside or new panel on outside.

Got a link?
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: MFowler on August 20, 2018, 04:44:11 am
https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70483;image (https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70483;image)


https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70160
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: sluckey on August 20, 2018, 05:10:58 am
Beldon noval tube sockets fit fine in the stock BJ holes without need for board inside or new panel on outside.
Those sockets look like Beltons to me. He added a tube so needed some kind of external plate to make it look nice.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: John on August 20, 2018, 06:30:16 am
Nice work, especially for a first build!


Like the Heathkit in the background too.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 06:48:38 pm
https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70483;image (https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70483;image)


https://el34world.com/Forum/index.php?action=dlattach;topic=23122.0;attach=70160

Hmmm, yes...
I used Belton sockets, but with the size of the Blues Junior chassis holes, there was really no way to make them fit and look nice.

Not saying my way is best, but with the plate I made, there are no gaps around the sockets to allow heat into the chassis.
(it gets hot enough with the tubes directly under it)

Plus the plate uses all those holes that originally mount the stock tube pcb.

Just a cleaner look really.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 06:49:17 pm
Beldon noval tube sockets fit fine in the stock BJ holes without need for board inside or new panel on outside.
Those sockets look like Beltons to me. He added a tube so needed some kind of external plate to make it look nice.

Yes, exactly!  :icon_biggrin:
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 06:51:33 pm
Nice work, especially for a first build!


Like the Heathkit in the background too.

Thanks!  :icon_biggrin:

 The Heathkit is a recent acquisition.
Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 06:54:07 pm
Here's a shot inside the chassis after I got the heater wiring done.


Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 07:18:06 pm
I kept all front panel control functions, including the FAT switch.

Here's how I did that.

Title: Re: Blues Junior hand wired conversion with tube reverb
Post by: galaxiex on August 20, 2018, 07:21:13 pm
Made a new back panel with a wider cutout for access to all the tubes, the fuse, and the heater hum balance.

The new MOD reverb tank is installed to better match the tube driven reverb.