Seafoam green princeton reverb clone

[TubeGeek]

Hi guys,

I wanted to share my latest project.  The electronic's are from a mojo kit.  The cabinet was custom built for me and I covered the amp in the sea foam green tolex.  It's my first attempt at applying tolex.

I increased the size of the speaker to a 12" and made the cabinet 2" taller than the original cab size.

The 6v6's I am using a marconi's.  The speaker is a Pyle from 1972…It came out of a fender amp.  I will try out several speakers before deciding but I'm liking this one so far.

 

[eleventeen]

Very surfy!

A Princeton Reverb w/12" is just about my ideal configuration. I have a '68 or so SF one, fueled w/6L6 & a Dynaco OT, that I really consider my best amp. I keep scrounging Craigslist for used PRRI's and they are at least 5x as rare as DRRI's. My next build project which I am all set up for will be a PR, stockish, 6V6 power, probably with an extra gain control, a middle control, and 2-knob reverb. I am waiting for a SS amp carcass to build it in and I found one, except the (Peavey Bandit) amp (for free) turned out to work! So I'm reluctant to tear it apart.

[Willabe]

Looks very nice!

Great job on the Tolex too!


             Brad     

[alerich]

I love my PRRI. I picked it up on closeout at GC a couple months ago. That creamsicle amp sat there for eons. I love it. It has always been my favorite Fender design. Love the bias vary trem instead of the roach. Love the cathodyne PI. I even like the stock Jensen 10" and the underrated OT. I think the amp is perfect the way it is. They did a nice job on this particular reissue. I sold my Goodsell Super 17 SN #0003 and don't miss it a bit. It was nice amp but nothing does a Fender clean like a Fender amp.

[TIMBO]

COOL 

[SILVERGUN]

Great work,,,,as always ....
Is that another one for the recording studio 

I'm gonna have to book some recording time next time I get north of the border.....it'd be nice to walk into a studio with nothing but a sandwich, and come out sounding like a million bucks...

That's quite an impressive arsenal you've got there!........thanks for sharing

[Willabe]

....it'd be nice to walk into a studio with nothing but a sandwich,

Make SG bring you a bag of Philly cheese steaks or no deal. (He lives in Philly.)


             Brad       

[TubeGeek]

Yes this is another one for my own collection.  I have stopped accepting work from other's so I can focus on working on my own projects that have been on hold.  I am having so much fun making these projects that I have wanted to do for a while, I may not open my shop doors for another month or two.

Can a guy ever have enough amps? Not me!

I've been building ribbon mic's this past month too.  I have finished 16 of them.  All in prep for a couple recording gigs coming up in December and January for me.

Back to this amp...

Last year I built the same circuit for a guy and that cabinet was a furniture grade african mahogany cabinet...when I picked up the cabinet from my cabinet builder friend, I noticed he had made a jig or template out of mdf.  I asked him if I could buy the template from him and he said yes.  The cabinet sat around for a year and then I decided to order some tolex and try my hand at covering a cabinet.  New skill = fun.

10 years ago when I tried to cover an amp with tolex I ended up stressing out and giving up.  I guess I have more patience these days because the task wasn't too bad this time around.  I have to say I feel proud of this one.  It was fun to see the final product come to light.

[TubeGeek]

If I wanted to strengthen the tremolo depth or intensity, how would I go about it?

It's nice but a little weak for my liking.

I also didn't like the large reverb tank that came with the mojo kit.  The verb was way to big for my liking so I used a smaller accutronics reverb tank I had lying around and it fit the bill.

[SILVERGUN]

Great job on the tolex....it's on my list, but I've been puutting it off because I'm not much for upholstery

Here's Sluckeys notes form his AB763 circuit with trem.....I'm imagining yours is similar

[sluckey]

If I wanted to strengthen the tremolo depth or intensity, how would I go about it?

1. Replace the oscillator cathode resistor/cap with a 5mm red LED.

2. Put a diode across the Intensity pot outer lugs.

[TubeGeek]

Made for each other!

[phsyconoodler]

Nice! Now I want one! I have the exact same strat too! I may build another little bastard amp and cover it the same as yours.

 Inspiring!
 

[TubeGeek]

How many yards of the tolex do you need?  I have some left over

[TubeGeek]

If I wanted to strengthen the tremolo depth or intensity, how would I go about it?

1. Replace the oscillator cathode resistor/cap with a 5mm red LED.

2. Put a diode across the Intensity pot outer lugs.

Tried both tonight and I get a deeper trem with the stock 3k3/25uF config.

Looks cool with the flickering LED though

Here is a recording of the stock tremolo:  https://soundcloud.com/glacier/seafoam-green-princeton-reverb

[tubeswell]

Nice amps tube geek!

I too love surfing' with my PR cloney thing (also uses a 12" - weber 12a125A, and a 6k6 25W OT). Makes my JM sound cool.

[TubeGeek]

Nice setup!

Here is where I am now with the tremolo:  https://soundcloud.com/glacier/seafoam-green-princeton

I have reduced the oscillator 1M plate resistor to 120k, removed the 0.022 uF cap to ground and biased the 6v6's a little cooler than what I had them at.

I like the depth now but I am hearing a little more distortion with the tremolo activated.  

I'll tweak some more...

[Tone Junkie]

Man I must be getting old, I get as exited over pictures of amps and guitars as I do girls. (LOL). Keep them coming guys love those amps and guitars.
I need to try one with that type of tremolo.
 phsyconoodler is the little bastard amp the one you added the extra gain stage to that you liked so much.
Bill

[tubeswell]

I like the depth now but I am hearing a little more distortion with the tremolo activated.  

Bias-vary trem naturally makes the output tubes run hotter (you can see this with the plate current going up when you kick the trem in). So its best to bias the output tubes on the cool side of normal (around 60%) for best results

[tubenit]

There is some info in ARCHIVES on tremolo mods right here:

http://www.el34world.com/Forum/index.php?topic=604.0

Maybe something in there will be useful to you?

Beautiful amp!  Very nicely done. Bravo.

with respect, Tubenit

[gtr2]

Awesome looking amp!

Josh

[lego4040]

  That is incredible and just says SURF MUSIC all over it. Im looking at doing MOJO'S PR and have been reading as much as possible on this forum(So Much Info). I hear good reviews on their products, Do you have any gut shots?? You nailed that tolex job as well.

[TubeGeek]

Guts

[tubeswell]

Nice wiring job!

May I suggest you consider putting some 1,000V 1A diodes in series with the HT winding and the rectifier tube anodes (to protect the PT against rectifier tube shorting)? (you can mount these between the surplus socket pins)

[eleventeen]

Irresistable color contrast between the green knobs & the orange drops!

[lego4040]

  Thats a super clean build and the soundclip was sweet.. What electro's came with the kit by way? Im probably gonna change some parts out when I order my kit, add the bias mod and tweak tremolo as well. I probably build it on the hoffman board as well. You said the Reverb was to Boomy for you? I havent looked her yet but Im wondering if there is a mod that will let you and dwell as well as mix instead of just the reverb. I already have been comparing Hoffmans super vibrolux build to the Princeton Reverb. Id build that but I dont need that power for playing in the apt

[TubeGeek]

Thats a super clean build and the soundclip was sweet.. What electro's came with the kit by way? Im probably gonna change some parts out when I order my kit, add the bias mod and tweak tremolo as well. I probably build it on the hoffman board as well. You said the Reverb was to Boomy for you? I havent looked her yet but Im wondering if there is a mod that will let you and dwell as well as mix instead of just the reverb. I already have been comparing Hoffmans super vibrolux build to the Princeton Reverb. Id build that but I dont need that power for playing in the apt

The electro's consist of a combo of sprague atom(bias cap), mojo wrapped 25uf's, and a JJ cap can.

I always change out parts in the kit.  Mojo sends out cc resistor's, as you can see I prefer metal film's.

I also used teflon coated wire, 18 awg cloth for the heaters.

Added 1k5 and 500 ohm resistors on the 6v6 sockets.

The reverb tank that comes with the mojo kit is a large 2 spring tank.  Sounds very deep and over the top reverb for me.  It's too much verb even on 2.  I had another 3 spring smaller tank around and used that instead.  I am considering adding a dwell or tweaking the verb too. For the meantime I am going to play it as is and enjoy it.

Oh I also added a little more mids by changing the fixed value mids resistor to 15k instead of the 6k8 value.

Experimenting with speakers....I have a vintage 30 installed at the moment.  I'm going to install a Weber 12f150 tonight and see what I like better.

[tubeswell]

 I'm going to install a Weber 12f150 tonight and see what I like better.

If its a new Weber, remember that they are harsh-sounding straight out of the box and they need some run-in time.

[TubeGeek]

 I'm going to install a Weber 12f150 tonight and see what I like better.

If its a new Weber, remember that they are harsh-sounding straight out of the box and they need some run-in time.

I pulled it out of my twin reverb for the comparison so it's been well used.

[lego4040]

Have you seen this guys Princeton Reverb Clone? http://www.jeangodbout.com/princeton/reverb-amp.html This guy went to town on replicating and making new parts look old, plus molding and painting parts etc. He also added a mid pot and made his own custom faceplate

[TubeGeek]

Well after trying out as many speakers as I can I have come to a conclusion…

Weber 12f150 is the winner.

I'm happy now.  Now onto the next project!