PRS J-MOD 100 (John Mayer)

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Bombacaototal
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Re: PRS J-MOD 100 (John Mayer)

Post by Bombacaototal »

I'm slightly intrigued with their built in buffered fx loop which as they describe it "does not affect the sound of the amp" in any way, different from a Dumble loop with d'lator which does darken the sound a bit

Any ideas on the circuit approach?
mc41
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Re: PRS J-MOD 100 (John Mayer)

Post by mc41 »

[quote=Bombacaototal post_id=368313 time=1486134525 user_id=16876]
The amp is 4x12AX7 with 4x6L6

I would assume it's a ODS like circuit but with a dumblator like buffer on the Loop. So V1=tonestack; V2=Overdrive; V3=d'lator loop; V4=PI
[/quote

In the Sweetwater video with PRS they say it is inspired by JM favorite amps and that the J-Mod as the SSS filters "glued in" , they adjust each plate voltage and feedback resistor with trimpot for the proto.
The preamp is probably very similar to SSS but with different plate voltage and negative feedback.
I think the "gain stage" is not a Dumble like OD but probably a DC coupled cathode follower like most SSS have in the clean/reverb mix section but with gain and level controls..It would sound very good for compression at low breakup but bad if driven hard.
I think it`s probably V1a > preamp/tonestack > V1b > filters > V2a (probably not a CF) > loop switch/controls/jacks and V2b(recovery) > V3=gain stage > Master > V4=inverter
frankdrebin
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Re: PRS J-MOD 100 (John Mayer)

Post by frankdrebin »

gutshot found online
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norburybrook
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Re: PRS J-MOD 100 (John Mayer)

Post by norburybrook »

that does look very nice inside with good components. I still don't like the sound of the OD however :D


M
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Colossal
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Re: PRS J-MOD 100 (John Mayer)

Post by Colossal »

norburybrook wrote: Wed Nov 13, 2019 5:28 pm that does look very nice inside with good components. I still don't like the sound of the OD however :D
M
I saw that demo video and for me, I really prefer his older sound...Fenders and the Two Rock. I did not care for the OD either. Thank you for posting that gut shot, Frank. Cool to see it.
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Guy77
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Re: PRS J-MOD 100 (John Mayer)

Post by Guy77 »

Thanks for posting this gut shot and as Colossal and Marcus mentioned I also do not like the overdrive on this, it sounds like its breaking up too much. I also prefer his older two rock amp sound and then just adding a tone stack lift for a boost. I see they used 2 fuses on the heaters and maybe others else where.
Guy
frankdrebin
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Re: PRS J-MOD 100 (John Mayer)

Post by frankdrebin »

you know what,i've been told that it's overdrive in front of a BF Fender style...kind of a reverse ods
beasleybodyshop
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Re: PRS J-MOD 100 (John Mayer)

Post by beasleybodyshop »

I like how the PSU layout looks....familiar.

And built using parts that entirely come from Mouser or CE distribution. Then again, many of the boutique builders do this and not a knock at all.

Panasonic film caps. Nichicon filters. Nothing magical under the hood. The cork sniffer Jensen PIOs in the phase inverter are interesting.
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
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FUCHSAUDIO
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Re: PRS J-MOD 100 (John Mayer)

Post by FUCHSAUDIO »

C Moore wrote: Fri Feb 03, 2017 6:34 pm
FUCHSAUDIO wrote:Agree on most of the above. I'd like to point out it's actually a single channel amp for $ 6-K apparently. Tolerable cleans, the OD sounds like a Hot Rod Deville to my ear...
Hey Andy -
I want to be clear, and fair.....i am not taking a cheap shot at Amp Builders. Not Doug Sewell or you or anybody else.
You guys have a right to do whatever you need to stay in business. You make more amps now than when you started.....OK, Fine.
But these Hugely Expensive and "Signature" amps.......how exactly do they differ from the Hundreds of amps that were made just before it, and the Hundreds of amps being made just after it.?
The idea that a 6K amp with a John Mayer badge on, must...Just Have To Be, something unique borders on the pathetic.
If we were to pry one of these thing open, would it not have many of the exact Same/Similar parts and RC circuits that we would find in a 1500-3000 dollar:
Soldano
Fuchs
/13
Carr
etc etc etc
My Apologies.
I have rambled...sorry, but this scenario seems to be past ridiculous.
I will say no more.
I agree, that at 6-K it looks like a big-ass money-grab for PRS. I know one dealer who still has the first amp in stock over a year. His demo videos show how bad it is...the buyer said "the ODS eat's this things lunch at half the price".....amazing we don't sell even more...
Proud holder of US Patent # 7336165.
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