Princeton Reverb build

[labb]

Had it with all of this virus lock down so I decided to build another amp...Going to build the Princeton Reverb circuit less the reverb and trem...Any helpful hints, suggestions or advice would be appreciated. As a starter I am going to use the 20 watt transformer sets. PT is 330-0-330, 120 ma. The OT is 20 watt, 8K primary, 4,8 and 16 secondary.

[tubenit]

Not sure why you don't want reverb or tremolo like on the original?   IF it's an issue of the number of tubes, you could do a one tube reverb PR.  Note some of the changes in this schematic from the original and compare carefully:

- cathode biased  (since not using the original tremolo & fixed biasing)
- .1 to .047 post LTPI coupling caps  (less issues with bass flubbing out)
- lower value cathode caps on the first 3 stages  (lower gain stages for more headroom)
- one tube reverb

NOT saying you "should" do this.  You asked for feedback, here is how I would approach it IF I needed to use less tubes.

with respect, Tubenit

[Dave]

No advice, that's pretty straight forward. However, things to think about.


1. Give it a LTPI. Most people love Princeton Reverbs, but the one complaint I hear is they don't like the PI.
2. Give it a mid control.
3. Cathode/Fixed bias.




Dave

[mresistor]

I like Tubenits ideas..   if you change the PI to long tail then it's not a Princeton anymore and won't sound like one.    Tell us..  why not build an 1164 Princeton Reverb as it is..  with Tubenits hints they
sound awesome..   and to some they sound awesome as is.     ?

[labb]

I'm not trying to build a PR clone. Just want to see what that circuit(1164) with the three gain stages and that PI sounds like. I just really don't see the need for Reverb or Trem in this build. Go get a pedal if that is what one wants. I have a stand a lone reverb unit 6G15 that I can plug into it. Lower cap values for the pre amp bypass sounds good(ala Marshall) may give that a go. Lower value coupling caps I will probably give a try if the bass is over powering. The mid control I plan on. Maybe a Raw Switch too. I'm kinda looking at this like a AB763 Deluxe Lite. Thanks guys, anything else...

[mresistor]

Well I have implemented a RAW pot in a couple of amps and really like it..   I like the adjustability versus the on off  static states.. I put the pot where the #2 input jack was and changed the grid stopper accordingly. I used a 250KA pot   but other values may be better.. like 1MA or 500KA ..

[punkykatt]

Do a google search AA1164D Princeton Reverb Delete. Should bring up a schematic and layout.

[DummyLoad]

an abomination of a mix of fender amps = no fenders - depicted in the attached is what i have derived from the conversation so far...

NFB is VERY light - decrease R29 to suit.

as drawn (-) bias is coldest with VR7 fully CCW. raw control is full roar with VR5 fully CW. R7 & SW2? yes, you're going to want those. this thing has LOTS of gain. you may great difficulty taming it.

about the stiff-ish PS: with as much gain as in the plan, you're definitely going to want that too. 


--pete

[ac427v]

I did this with a different master volume. I used a dual 1 meg pot and two extra .1/630v caps for a traditional PPIMV. Loved it!

[labb]

Well finally got this project off of the ground.All of the chassis work is done. Dry fitted all of the hardware to make sure all fitted including the face plate. Board layout is done but have not built the board just yet. Today, hopefully, I will wire up the 120 volt stuff and the rectifier tube. Also hope to get the heaters wired up..my least favorite thing to do. Probably because I am not very good at it. I am not very happy with this amp. I used Robrob's layout and it is not as straight forward as most of the Fender amps I have built..Using a cap can for the first time and it really screws up the grounding scheme I normally use. Just maybe I fire this thing up and it sounds better that most of the amps I have built. We shall see. At least this project keeps me at home, not a problem with "Social Distance" or facemasks. All take care and be safe...