Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: EL34 on August 13, 2014, 05:42:44 pm

Title: My Princeton Reverb build
Post by: EL34 on August 13, 2014, 05:42:44 pm
I am building a Hoffman Princeton Reverb board and installing it in a generic Fender style chassis with Face plates.
I will be stocking the princeton reverb chassis and the face plates shown below and so I wanted to make sure this build goes together as planned
Should be a fun project.

Today I swagged the lugs into the board
Laced the board
Soldered the laces in place.

That's as far as I can go until I mount the board in the chassis because I like to wire up my boards with no parts on the board.
The parts get added after all the wires have been installed to the tube sockets
I do the pot wires last

I started a build page here with some pics
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)

I'll add more pics and update the page as the build proceeds.

http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)

(http://el34world.com/Hoffman/images/Img_8390_small.jpg)
Title: Re: My Princeton Reverb build
Post by: simonallaway on August 14, 2014, 09:36:07 am
What are your plans for the finished amp? Will this go into a combo cabinet with a speaker? Or a head?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 14, 2014, 10:00:20 am
Hi Simon,
I am doing this so I can take How-To-construction pictures for the web site
I have enough amps here already so I won't be keeping the amp

It will get tested with some sort of speaker cabinet here and then I will be selling the completed working chassis
I'll probably do another one of those Cost of parts only, no labor deals

The new owner will need to get a princeton reverb cabinet, speaker, reverb tank and bag
Mojo has the cabinet and speakers, I have the tank and bag


Title: Re: My Princeton Reverb build
Post by: simonallaway on August 14, 2014, 10:18:48 am
Cool. I'll be watching for updates as I'm jonesing to build one myself.
Title: Re: My Princeton Reverb build
Post by: EL34 on August 14, 2014, 10:24:18 am
I may be able to get the board mounted in the chassis tomorrow and get some more pics taken
I'll post back when I have more updates
Title: Re: My Princeton Reverb build
Post by: EL34 on August 15, 2014, 10:32:12 am
I just added a bunch of new pics to the build page here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)


Go to the page above to see very large images

Plugging away at it today. I have all the bolt on stuff in place.

Time to start soldered up the tranny wires, heater wires, switch and fuse, filter cap wires

I am making detailed notes as I go regarding all the screws, nuts, grommets, etc I am using for the build
I will have a very accurate parts list when I am done

I will be stocking this chassis and the face plates and so I wanted to make sure this build goes together as planned

(http://el34world.com/Hoffman/images/Img_8402_small.jpg)
Title: Re: My Princeton Reverb build
Post by: simonallaway on August 15, 2014, 11:12:43 am
Looking good.
Is that your 40x20x20x20 cap in there?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 15, 2014, 11:16:52 am
Yeah,
It's a JJ 40x20x20x20


I decided since the chassis has a cap hole to use that cap and a cap bracket.
40uf on the B+ is more than a stock Princeton but I like a bit more on that stage in all my amps
Title: Re: My Princeton Reverb build
Post by: EL34 on August 15, 2014, 02:25:10 pm
Getting there slowly
Got most of the infrastructure wiring done
more pics here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)


(http://el34world.com/Hoffman/images/Img_8406_small.jpg)


Title: Re: My Princeton Reverb build
Post by: lego4040 on August 16, 2014, 07:17:41 am
 :worthy1: Excellent. That is a work of art and the pictures alone are worth a million
Title: Re: My Princeton Reverb build
Post by: EL34 on August 16, 2014, 09:10:51 am
Thanks


More to come
Title: Re: My Princeton Reverb build
Post by: EL34 on August 16, 2014, 12:31:42 pm
Got a bit more wiring done today
Lots of wire in this amp
Takes time to figure out good wire routing

Bigger pics are here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)

(http://el34world.com/Hoffman/images/Img_8407_small.jpg)
Title: Re: My Princeton Reverb build
Post by: EL34 on August 16, 2014, 04:07:58 pm
That's it for today
Heater wires are always the least fun for me

All the wires have been installed except the pot wires, which I will do last after the parts are on the board

bigger pics here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)


(http://el34world.com/Hoffman/images/Img_8411_small.jpg)
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 16, 2014, 08:14:01 pm
Interesting that you do board that way but it makes total sense to me. No flying leads to battle with when installing board and you waste less wire. Plus the board has a sturdy place to be held
Title: Re: My Princeton Reverb build
Post by: EL34 on August 16, 2014, 09:09:26 pm
Doing it this way, you don't mess up the parts leads when installing the wires.
It's not easy to install all those wires with a bunch of stuff in your way

If the parts were mounted on the board, there no way that you would not bend some of them
I probably dropped my wire cutters onto the board 10 times during the wire installs

Plus, some of the wires are down a few rows on the board and the best way to route them is under some of the parts

As you said, the wires are cut to the exact size with no waste

The parts leads will all be perfect and straight when installed last

I like my board installs to look as good as they sound  :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 17, 2014, 02:21:54 pm
Got the parts installed on the board

Next comes the pot wires and then it will be time to fire it up

Bigger pics here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)


(http://el34world.com/Hoffman/images/Img_8412_small.jpg)


Title: Re: My Princeton Reverb build
Post by: sluckey on August 17, 2014, 02:58:09 pm
That's just plain purty!
Title: Re: My Princeton Reverb build
Post by: EL34 on August 17, 2014, 05:14:19 pm
It's done!

Finished the pot wires
Fired it up, set the bias to 30ma as a general test setting
Checked all the voltages, everything looked great

Plugged it into a Marshall 4x12 cab set at 8 ohms
Plugged in the guitar and gave it spin

It's a cool sounding amp
The reverb is great

After I change my 3 month old strings I'll do a video demo of it  :icon_biggrin:

More info and bigger images here
http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm (http://el34world.com/Hoffman/Princeton_Reverb_Board_Build.htm)


(http://el34world.com/Hoffman/images/Img_8415.jpg)
Title: Re: My Princeton Reverb build
Post by: pullshocks on August 17, 2014, 05:24:18 pm
Very cool, could you post a shot from the back.  Thanks.

I want to do something like this but with 1 tube reverb and no vibrato.
Title: Re: My Princeton Reverb build
Post by: tubenit on August 17, 2014, 06:06:43 pm
Doug,

That is just flat out magnificent!  What an incredibly well done build.

With respect, Jeff
Title: Re: My Princeton Reverb build
Post by: EL34 on August 17, 2014, 06:24:43 pm
Very cool, could you post a shot from the back.  Thanks.

I want to do something like this but with 1 tube reverb and no vibrato.

Did you want a shot other than what is on the build page?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 17, 2014, 06:28:22 pm
Doug,

That is just flat out magnificent!  What an incredibly well done build.

With respect, Jeff
Ah, just another day at the office.  :l4:

I may do some other builds and document them

The Hoffman Turret board sales really picked up after I posted all the new Layout Diagrams
The boards seem more doable to people when you have a nice diagram to follow
Title: Re: My Princeton Reverb build
Post by: tubeswell on August 17, 2014, 08:00:19 pm
Very tidy
Title: Re: My Princeton Reverb build
Post by: Willabe on August 17, 2014, 08:04:14 pm
Ah, just another day at the office.  :l4:

     :laugh:

Really top of the line work!


I may do some other builds and document them
The Hoffman Turret board sales really picked up after I posted all the new Layout Diagrams
The boartd seem more doable when you have a nice diagram to follow

Your new drawings are great! Very clear and very helpful. I think it's like with Sluckey's drawings of his builds, it's makes it soooooo much easer to build 1 then if there's just a electrical and layout schemo like Fender.

I think it will inspire a good number of guys to do some new builds.


                      Brad     :bravo1:         
Title: Re: My Princeton Reverb build
Post by: DummyLoad on August 17, 2014, 09:37:40 pm
nice looking build doug!   :icon_biggrin: 


--pete




Title: Re: My Princeton Reverb build
Post by: bigsbybender on August 17, 2014, 11:31:23 pm
Beauty!!   So clean!




j.
Title: Re: My Princeton Reverb build
Post by: EL34 on August 18, 2014, 06:02:29 am
Thanks all
The Princeton is a perfect sized gigging amp for small venues if you are doing a single or have a quiet band

It would not work for a Blue Cheer tribute band  :l2:

I think a Hoffman Stout in a Champ Chassis may be next
My Stout is a really cool little amp

(http://el34world.com/projects/images/DSCN1699.JPG)
Title: Re: My Princeton Reverb build
Post by: tubenit on August 18, 2014, 06:18:55 pm
Quote
I think a Hoffman Stout in a Champ Chassis may be next.   My Stout is a really cool little amp

Given your great relay switching resources ................. are you considering setting up  V1b to be more like your "hotswitch" for the larger Marshalls?

With respect, Tubenit
Title: Re: My Princeton Reverb build
Post by: Willabe on August 18, 2014, 06:46:23 pm
Ooooooooh, good suggestion.


                Brad     :think1:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 18, 2014, 06:53:14 pm
That relay stuff in the stout was just an experiment

I never switch the extra gain stage off
The amp sounds way better with it on full time

It will go from clean to mean with the switch on

The amp sounds a bit dull with the switch off

I don't see any need to have any relay switching stuff in the amp

I am working on a source to have some Stout chassis made
A small sized chassis like the box I used, with all the holes in the chassis, ready to start assembling
The chasis would be 12 inches x 7 inches x 2.5 inches
Title: Re: My Princeton Reverb build
Post by: EL34 on August 18, 2014, 07:14:55 pm
I filmed a few videos today of the Princeton in action
This amp is really cool
Congrats to bigsbybender, it's his amp now.

It will take a while to upload the other videos

This one just finished uploading
http://youtu.be/0ShPbbuZs18 (http://youtu.be/0ShPbbuZs18)
Title: Re: My Princeton Reverb build
Post by: Willabe on August 18, 2014, 07:38:22 pm
Can we hear something with the trem too?


            Brad     :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 18, 2014, 07:45:34 pm
There is a short trem section in the video around the :47 mark

The tremolo is not that strong or deep compared to the ReVibe
I am spoiled after playing the ReVibe
Title: Re: My Princeton Reverb build
Post by: tubenit on August 18, 2014, 08:21:40 pm
Hey, I thought the trem sounded excellent!   Thanks for sharing the video.  Cool stuff. 

Title: Re: My Princeton Reverb build
Post by: DummyLoad on August 18, 2014, 08:54:57 pm
reverb sounds really nice! trem sounds good too.



 
Title: Re: My Princeton Reverb build
Post by: bigsbybender on August 18, 2014, 11:24:07 pm
Oddly enough I play 3 of the songs you did in my Psychobilly band. I've wanted to try a Princeton Reverb instead of the 5E3 deluxe I use... This was the perfect opportunity.

Glad I asked if it was available!

Thanks again Doug!
Title: Re: My Princeton Reverb build
Post by: drew on August 19, 2014, 01:02:03 am
Are the two turrets in the power rail that don't have any components or wires attached to them just there to keep the buss wire spans relatively short?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 06:02:43 am
Are the two turrets in the power rail that don't have any components or wires attached to them just there to keep the buss wire spans relatively short?


Hi Drew,
You guess it,
I found out that the one on the left end is not needed and so I removed it from the new layout
The one on the right side is there to help span a really long gap
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 06:03:48 am
Oddly enough I play 3 of the songs you did in my Psychobilly band. I've wanted to try a Princeton Reverb instead of the 5E3 deluxe I use... This was the perfect opportunity.

Glad I asked if it was available!

Thanks again Doug!


Welcome
I think you are really gonna like this amp
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 06:24:41 am
Here's another vid of the Princeton Reverb in action


I bumbled through Slaughter on 10th avenue


http://youtu.be/TKV2Z4ievOU (http://youtu.be/TKV2Z4ievOU)


Title: Re: My Princeton Reverb build
Post by: DummyLoad on August 19, 2014, 06:28:42 am
video above permissions are set to private - cannot view...


--pete
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 06:48:22 am
Thanks for the heads up
That one uploaded last night and I did not finish editing it
Should be good to go now
Title: Re: My Princeton Reverb build
Post by: shooter on August 19, 2014, 08:42:46 am
is the chassis a natural patina or did you create that look?  I like it!
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 09:00:08 am
It comes that way
It's really thick metal and spot welded really well

I will be ordering some for stock this week
And I'll put the faceplates in staock also

The chassis can also be used for Stout Reverbs, which is what mine is built into
That project is on this page
http://el34world.com/projects/18WattStoutReverbNoSwitch_1.htm (http://el34world.com/projects/18WattStoutReverbNoSwitch_1.htm)




(http://el34world.com/projects/images/DSCN1834.JPG)
Title: Re: My Princeton Reverb build
Post by: eleventeen on August 19, 2014, 11:59:09 am
I definitely like the way the corners & folds are executed on that chassis versus the mojo chassis---not saying it makes any difference at all and it's probably invisible, I just prefer the more "Fendery"style or what you have pictured.
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 12:02:32 pm
I definitely like the way the corners & folds are executed on that chassis versus the mojo chassis---not saying it makes any difference at all and it's probably invisible, I just prefer the more "Fendery"style or what you have pictured.


The chassis in the post right above is a real Fender princeton reverb chassis
I think the Mojo chassis is better built actually after seeing both of them
Title: Re: My Princeton Reverb build
Post by: eleventeen on August 19, 2014, 12:11:41 pm
Well, then that explains why it looks Fendery! From a reissue or something you had laying around?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 19, 2014, 12:16:01 pm
It's a 70's princeton reverb chassis. Don't remember the year
I got it some time in the 90's
Title: Re: My Princeton Reverb build
Post by: EL34 on August 20, 2014, 05:37:01 am
Finally got all 4 videos uploaded
Could only do it at night because they were so huge


http://youtu.be/JdVN5TdOk1k (http://youtu.be/JdVN5TdOk1k)
http://youtu.be/0ShPbbuZs18 (http://youtu.be/0ShPbbuZs18?list=PLVvDFekIYJjflOUPVAV9ENuznt6IgBF4_)
http://youtu.be/TKV2Z4ievOU (http://youtu.be/TKV2Z4ievOU?list=PLVvDFekIYJjflOUPVAV9ENuznt6IgBF4_)
http://youtu.be/IiZzRmvTbco (http://youtu.be/IiZzRmvTbco)
Title: Re: My Princeton Reverb build
Post by: EL34 on August 20, 2014, 09:01:17 am
I definitely like the way the corners & folds are executed on that chassis versus the mojo chassis---not saying it makes any difference at all and it's probably invisible, I just prefer the more "Fendery"style or what you have pictured.


I have seen this happen to fender chassis way more than one time
Mostly on the longer chassis

Title: Re: My Princeton Reverb build
Post by: DummyLoad on August 20, 2014, 09:55:25 am
I definitely like the way the corners & folds are executed on that chassis versus the mojo chassis---not saying it makes any difference at all and it's probably invisible, I just prefer the more "Fendery"style or what you have pictured.


I have seen this happen to fender chassis way more than one time
Mostly on the longer chassis


richard and i have had two super reverb amps come through my shop with similar dents. one them was dented front and back. i hammered on a 2x4 on wood bench for backing to beat out the dents.


--pete
--pete
Title: Re: My Princeton Reverb build
Post by: Willabe on August 20, 2014, 01:41:48 pm
That'll work.

You can also use a 2"x4" in front and another in the back/inside of the chassis a use a strong clamp to straighten it out too.

Might have to add a few shims on the ends of the outside wood block to be able to 'over bend' the chassis just a little for spring back?


                          Brad    :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: eleventeen on August 21, 2014, 12:07:13 am
What are we comparing here? A 40-year old real Fender built up into an amp with the weight of the trannys and speakers in one cabinet that fell over and hit the knobs on something and thus dished in the front panel, with a brand new chassis? A Mojo chassis subject to the same impact on the knobs would suffer the same kind of dentage.
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 06:57:28 am
Not saying the Mojo chassis will not bend


Was just saying that I have seen plenty of the fender chassis that were bent

Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 07:11:57 am
Oh Man, Doug that sounds fantastic. You nailed that sound, verb and tone. I know what my next build is
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 07:18:59 am
yeah, It's a great amp


I should have the chassis and faceplates in stock by next week
I sell them cheaper than the supplier does
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 10:34:00 am
That's great, what's next on the project list? How about a Tremulox build?
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 10:42:52 am

Quote
That's great, what's next on the project list? How about a Tremulox build?

Na,
It would be one of the Hoffman Boards I already make

I am thinking Stout as soon as I get my hands on the custom chassis I designed

It will look about like the Amp chassis I used here
12 inches x 6.5 inches x 2.5 inches

Mojo and I am working together on the chassis
They already make a Marshall 20 watt head cabinet that this chassis can go into
Although the stock Mojo 20 watt head cab is kinda long for a small chassis like this
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 11:12:29 am
That's your Marshall version amp, I remember that. Too many amps to build, I started putting some jigs together so I can dust off my wood working skills and make two heads for my last to builds
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 11:28:52 am
18 watt Marshall circuit with extra gain stage


It's one of my favorite amps
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 12:28:26 pm
Is it BluesBreakerish? Ala Clapton? I'd probably be able to convert my other amp into one
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 12:36:00 pm
Here's a couple Stout clips
Tone totally depends on the pickups and volume settings on the amp and the guitar
single coils will be completely different from Humbuckers

Stout without reverb
Bad timing on the entry to Thrill
http://el34world.com/Misc/Music/files/Thrill.mp3 (http://el34world.com/Misc/Music/files/Thrill.mp3)

Stout with reverb
http://el34world.com/Misc/Music/files/BadGirl.mp3 (http://el34world.com/Misc/Music/files/BadGirl.mp3)
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 02:07:22 pm
That's hot
Title: Re: My Princeton Reverb build
Post by: TIMBO on August 21, 2014, 02:14:22 pm
I'll second "that's hot" :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 02:24:14 pm
That second ZZ clip rocks pretty good
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 02:40:18 pm
Sometimes you need a certain amp and guitar to get a certain sound. Since I was twelve all I wanted to be was Angus Young, that was 30+ years ago when my Uncle introduced me to Let there be Rock and showed me photos  of their concert in California where he Bon Scott. That's a sound only Marshall can get
Title: Re: My Princeton Reverb build
Post by: tubeswell on August 21, 2014, 03:04:36 pm
Nice clips of the PR there Doug
Title: Re: My Princeton Reverb build
Post by: EL34 on August 21, 2014, 03:41:08 pm
Thanks
Title: Re: My Princeton Reverb build
Post by: bigsbybender on August 21, 2014, 08:31:03 pm
Just unpacked!

Clips to come this weekend!

J.
Title: Re: My Princeton Reverb build
Post by: lego4040 on August 21, 2014, 10:50:04 pm
 :worthy1: Lucky SOB, did you get Doug to Sign Chassis? To me I see his work in par with all the big amp names
Title: Re: My Princeton Reverb build
Post by: bigsbybender on August 21, 2014, 10:58:43 pm


:worthy1: Lucky SOB, did you get Doug to Sign Chassis? To me I see his work in par with all the big amp names



I can't believe nobody called dibs before I did! It was a perfect storm, as I was about to spend money to build (or rebuild) a Princeton, I saw this one was available and Doug wasn't charging labor so I thought I'd go for it.


Love these small combos!


j.

Title: Re: My Princeton Reverb build
Post by: Willabe on August 21, 2014, 11:36:07 pm
Just unpacked!

That was Fast!


          Brad      :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 22, 2014, 05:24:48 am
Glad to see it arrived in one piece


Definately get some clips for us  :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: alerich on August 22, 2014, 01:43:51 pm
Great work, Doug and an outstanding amp.

Many people feel that the Super Reverb is the high water mark of the Fender line. I do not share that opinion. I have always loved the Princeton Reverb and I think it's the finest amp that Leo ever conceived.
Title: Re: My Princeton Reverb build
Post by: EL34 on August 22, 2014, 01:47:29 pm
yeah, it's a great circuit for sure

Title: Re: My Princeton Reverb build
Post by: Willabe on August 22, 2014, 04:15:47 pm
Apples to oranges, their stage output volume is way different.

Different amps for different jobs/gigs.


                   Brad     :icon_biggrin:
Title: Re: My Princeton Reverb build
Post by: EL34 on August 22, 2014, 06:04:28 pm
Paired up with my Marshall 4 x 12, that Princeton reverb could handle just about any gig

Of course you would have to haul a 4 x 12 Marshall cabinet to the gig  :icon_biggrin: