Princeton Reverb Hoffman Layout

[beasleybodyshop]

I am using the attached layout for my PR build.

I noticed that it has a wire running from pin 8 of the rectifier to the first dropping resistor, and then from that to ground - is this correct? I didnt see it on the original PR layout. My first thought is that it would pretty much send the B+ to chassis (!) can anyone confirm this for me? I don't want to follow this layout if its not going to be safe.

[overtone]

I'm not seeing what you describe, but i have not had any coffee yet this morning.

From pin eight of the rectifier there is a run to a standby-switch and then on to a turret that acts as a junction. One of the leads from that, goes to the CT of the OT and by the way that it is drawn one could mistakenly assume that it goes to the ground lug. Is that what you mean?

[ToneMerc]

Looking at the layout there's only 3 terminations ( bias, filter cap, HT center tap) drawn contacting those ground lugs. The OT B+ primary passes under the rightmost ground terminal.

TM

[beasleybodyshop]

Looking at the layout there's only 3 terminations ( bias, filter cap, HT center tap) drawn contacting those ground lugs. The OT B+ primary passes under the rightmost ground terminal.

TM

Aha! I see it now. its a red wire that goes underneath the ground lug, not too it. I knew something was up lol!

[ToneMerc]

Looking at the layout there's only 3 terminations ( bias, filter cap, HT center tap) drawn contacting those ground lugs. The OT B+ primary passes under the rightmost ground terminal.

TM

Aha! I see it now. its a red wire that goes underneath the ground lug, not too it. I knew something was up lol!

You are taking the right approach, verifying the circuit schematic verses a layout. In this case, this known layout is fine but could propose a problem with someone who simply "solders by numbers" not understanding the circuit and or someone not paying close attention to the drawing.

TM

[M Fowler]

I never understood why people liked this style of board layout in the first place easy to make a mistake and it happened.

[beasleybodyshop]

I never understood why people liked this style of board layout in the first place easy to make a mistake and it happened.

Right on Mark, next one I do will be following Fender's layout. Can't beat the original i suppose.

[Milkmansound]

gotta agree with Mark on that. That right there is a terrible layout for the Princeton Reverb - much more complicated and ugly than the original Fender.

Stick to Fender, but use a G10 board - thats a recipe for winning!

[beasleybodyshop]

In retrospect, I wish I had just used the fender layout.

Dammit.

Well I'm just going dance with the one I brung.

If she works, well I'm just going to count my blessings and carry on.

[xtian]

Well, gotta say I like Hoffmann's layout, and it worked great in my build!

[EL34]

I just created a bunch of new layouts for my boards using Visio
They are really nice and very east to follow

Check out the new Princeton reverb layout and BOM here
http://el34world.com/schematics.htm

Layout and schematic PDF
http://el34world.com/Hoffman/files/Hoff ... Reverb.pdf

BOM PDF
http://el34world.com/Hoffman/files/Hoff ... rb_BOM.pdf

And this PDF explains some of the things going on in my layouts
http://el34world.com/Hoffman/files/CommonHookups.pdf

[img:400:231]http://el34world.com/Hoffman/images/Hof ... _small.gif[/img]

[xtian]

Siiiikkkk! So cool.

Just one question.

http://el34world.com/Hoffman/files/Hoffman_AB763_1.pdf

What kind of 0.1uF caps will fit between those turrets? That's a very, very small space.

[EL34]

Xicon and Mallory 150's are no Problem

Sprague orange drop .1/600v's are really huge.

It'a not so much a problem lead to lead on most lug spans

It's that they are super wide. More like pregnant caps

[xtian]

Don't I know it! Modified your layout to accommodate orange drops:

https://tubeamparchive.com/download/file.php?id=33320

Screw Fender. I like Hoffman-style!

[telentubes]

I found that the Fender layout had too much crammed into too little space so I
spread things out a bit and changed the a few things that didn't flow too well. Here are a couple of pictures of what I came up with. Lovely amp. Very quiet with lush reverb and groovy tremelo.
I recently changed it over to run 6L6s and like the change.
It's a Weber chassis, with Allen iron.