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Princeton FSR Tweed

sonar

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Jan 10, 2003
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With this PR I get to use the tone controls on my LPs more and also on the amp(compared to the 1974X).........gradually getting used to its nuances.......it's beginning to sound really good.

Fantastic!

Once you get used to it, PR’s are a blast to play. After all this time I still get such satisfaction with the fun factor of a cranked up PR.
 

toxpert

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For printed circuit board PR amps, I swapped out the stock output transformer to a Heyboer/Allen Amplification T020 upgrade (BillM mod). This change preserves the PR tone but gets rid of low end flabby/woof distortion. The swap is very simple and fits existing mounting holes.
 

goldtop0

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For printed circuit board PR amps, I swapped out the stock output transformer to a Heyboer/Allen Amplification T020 upgrade (BillM mod). This change preserves the PR tone but gets rid of low end flabby/woof distortion. The swap is very simple and fits existing mounting holes.

Is this an upgrade from the existing Heyboer trannie that is in my one, do you know ?
Thanks.
 

sonar

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Is this an upgrade from the existing Heyboer trannie that is in my one, do you know ?
Thanks.

It's essentially a low profile Deluxe OT. Also made by Heyboer, designed by Dave Allen and BillM. More iron, more mass and turn ratios gives a core size that provides a higher damping factor. Basically helps with (you guessed it) low frequencies. Notice the trend with PR mods?

It's not a new idea for a modification. For whatever reason(s) the original PR chassis had holes punched out for a Deluxe output transformer mount. Players for the past 50+ years have been swapping out for a Deluxe Transformer and 12" speaker, transforming the PR from a 12 watt student amp into a portable club amp. Randall Smith would take this idea much further developing the Mesa Boogie Mark I using the PR chassis and cabinet, but that's another thread.

I agree that the general flavor of a PR is still there with a bigger output transformer, but you do lose some PR funk. The amp will grind a little less, sacrificing some of the fun factor. BillM (RIP) described the overdrive characteristic of the original PR transformer as a "blat." That's pretty much gone.

Again a trade-off. Do you want a classic PR with all the strange characteristics that make it such a unique Blackface amp, or do you want an amp that is slightly less funky, yet enough amp to use with a drummer?

Fwiw I built my clone to be a band amp and went with the TO20. You buy a few more useable watts, more than bumping up the first filter stage.
 

goldtop0

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It's essentially a low profile Deluxe OT. Also made by Heyboer, designed by Dave Allen and BillM. More iron, more mass and turn ratios gives a core size that provides a higher damping factor. Basically helps with (you guessed it) low frequencies. Notice the trend with PR mods?

It's not a new idea for a modification. For whatever reason(s) the original PR chassis had holes punched out for a Deluxe output transformer mount. Players for the past 50+ years have been swapping out for a Deluxe Transformer and 12" speaker, transforming the PR from a 12 watt student amp into a portable club amp. Randall Smith would take this idea much further developing the Mesa Boogie Mark I using the PR chassis and cabinet, but that's another thread.

I agree that the general flavor of a PR is still there with a bigger output transformer, but you do lose some PR funk. The amp will grind a little less, sacrificing some of the fun factor. BillM (RIP) described the overdrive characteristic of the original PR transformer as a "blat." That's pretty much gone.

Again a trade-off. Do you want a classic PR with all the strange characteristics that make it such a unique Blackface amp, or do you want an amp that is slightly less funky, yet enough amp to use with a drummer?

Fwiw I built my clone to be a band amp and went with the TO20. You buy a few more useable watts, more than bumping up the first filter stage.




Yes the trend is very evident isn't it.
I don't need the extra grunt in terms of output and am happy with the PR as I'm getting more used to it. Good to know that these things can be done however, helpful information. This amp has a good deal of volume.
Interesting that you should mention Randall Smith.........I sold a lot of Mesas in the '90s when working in a music equipment import business.
Yes a 'blat' is how I'd describe the overdrive also.........it's an in your face 'krang splat' which is endearing and different to what I've experienced with Marshall amps:lol
 

goldtop0

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Further to this I tried an old Jensen C12N in it and my 74 1772 alnico Celestion..........the 74 won hands down and was surprisingly more efficient than the Gold in the amp.
It has a very good and much better hold on the bottom end at high volume(also compared to the Blue) and shimmers/chimes everywhere else, the best match by a long shot.
I've just got to get rid of a bit of voice coil rub in it is the only thing.........mind you it is a 1954 vintage speaker so what can you expect after all these years.
 

goldtop0

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I've made the Blackface 65 AA1164 clone with the Cannabis Rex and it's sound amazing :)


That's good to hear.
There's a mix and match that goes on with any new amp I get(which is only once every few years), for example instead of the Celestion G12M20 in the 1974X Marshall I have either a Blue or a T1088, they provide the better tone and performance. It's horses for courses......... but in recent times I've opted for alnicos in my combos and 2x12 cabs.......for me they give a richer rounder sound..........it's all subjective this stuff.
 

goldtop0

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Care to explain your comment?


He's copied/parroted my post #2 at the top of the thread........for some reason:hmm
and changed the content of my post quote #4 as above also.
 
Last edited:

goldtop0

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I messaged the moderator and he's removed zimki's post.

Thanks Cogswell.
 

sonar

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I messaged the moderator and he's removed zimki's post.

Thanks Cogswell.

I did the same.

This isn't the first time something like this has happened on the LPF. I started a thread in Backstage about similar instances.
 

goldtop0

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I did the same.

This isn't the first time something like this has happened on the LPF. I started a thread in Backstage about similar instances.


Thanks for that.
First time for me.
 

goldtop0

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The overdriven tone in this amp is growing on me and in fact I'd describe it as an almost Peter Green type sound as he used reverb on a number of his tunes way back when.
 

goldtop0

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Tried my PR today with a 2x12 cab(60w).........straight out of the amp into the 2x12........made a big difference to the overall sound....a lot smoother and manageable when overdriven.
I don't know what it is about the circuitry of this amp but it certainly spanks and crunches a single 12" speaker.
 

deytookerjaabs

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My '65, after many swaps, has settled into a 60's Oxford 12" from a Twin Reverb. Mine is pretty bright/clear and doesn't fatten up much, the bass goes from "right there" to "too much" fairly easily. Which, makes it a hell of a smooth overdrive sound with humbuckers and throaty/bright with single coils. I've never run it past "5" on the dial and it just sounds wonderful. The modern reissue '68 Customs get pretty close to the sound of my '65 and with similar speakers probably real close. I'm not sure what's up with yours overall, it should be a heck of a great sounding amp for overdrive tones and especially with humbuckers. I prefer other Fender amps for clean/fat country/blues stuff though.
 

goldtop0

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My '65, after many swaps, has settled into a 60's Oxford 12" from a Twin Reverb. Mine is pretty bright/clear and doesn't fatten up much, the bass goes from "right there" to "too much" fairly easily. Which, makes it a hell of a smooth overdrive sound with humbuckers and throaty/bright with single coils. I've never run it past "5" on the dial and it just sounds wonderful. The modern reissue '68 Customs get pretty close to the sound of my '65 and with similar speakers probably real close. I'm not sure what's up with yours overall, it should be a heck of a great sounding amp for overdrive tones and especially with humbuckers. I prefer other Fender amps for clean/fat country/blues stuff though.


I give all my amps/combos a good workout and dime them at home to check their capabilities every so often.......with 5 -7 dialled in on the volume there is no problem with the PR's sound it reacts very well and sounds good however when I go 8-10 you notice the 'spank' come to the fore......a different more in your face overdrive compared to the compressed tone of a DR and 1974X at high volume.
 
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