Friedman Mini

[equinox]

Posting this as it's a pedal with a Class D amp and FX loop.

Would be nice to have a schematic created and see the difference between this and the BE-OD Deluxe and how to modify it to make it even better.

There are 3 board:
1. The Main board (this one, which is the preamp (pedal). I think the FX Loop is on it, but haven't gone thru it.
2. The Amp board (SMD)
3. The Output board which has the speaker outputs and the fx loop return and send.

I will be taking apart and reversing the other 2 board, possibly this weekend.

Enjoy!

 

[spi]

I think @Robert gave one of these away in a contest a few years ago, so maybe he traced it.

 

[equinox]

I think @Robert gave one of these away in a contest a few years ago, so maybe he traced it.

We'll see.

I sent contacted him in parallel in regard to the above PCB layout. If he didn't do it before, he could create a schematic from mine. Should be 100%.

I have 3 of the mini heads (BE, SLO, and Bogner). Of the thee, I like the SLO the best and BE the least with the Bogner in the middle.

The issues with the BE are for whatever reason, maybe diode clipping and too hard and pulling the signal down too far, but it's not as loud and I would say although can get fairly loud, cannot keep up with a full band and especially with a dynamic drummer.

However, I think the SLO and Bogner can keep with even with a dynamic drummer!

I'd like to modify the BE and in a few ways...really it's too much gain.
I'd like to taper it back more to a Plexi amount of gain and then hit the front-end with a pedal for super gain and saturation for solos.
The tone is too scooped and needs more Mids....either adjust the voicing or maybe add a Bright switch?
I'd like to add a clean, even if a simple one-knob volume clean with a 3-way bright switch.
Id like the 2-channels relay foot-switchable.
I'd like the FX Loop switchable, so FX loop can be turned on and off.

Once the schematic is understood, the MODing can be determined.

 

[Robert]

Yeah I traced the main effect PCB and most of the PM-30 module (if I recall most of that is from the TPA datasheet).

This isn't verified, double-checked, nothing.... don't trust it.

 

[equinox]

Yeah I traced the main effect PCB and most of the PM-30 module (if I recall most of that is from the TPA datasheet).

This isn't verified, double-checked, nothing.... don't trust it.
View attachment 110171

Thanks Robert!

Yeah, let me audit it versus the PCB this afternoon, which should be 100%!
I'll let you know and mark up any changes needed on the schematic.

I'll be doing the same to the amplifier and output boards this weekend, but need an SMD hot air workstation coming in Sat/Sun. So those two would be by next weekend and get the entire MINI 100%. The amplifier and output board are the same on ALL mini's, so it's only variations in the preamp (main) board that make them variants and to commonize things!

Thanks for your support!!

 

[Robert]

so it's only variations in the preamp (main) board that make them variants and to commonize things!

Yes, I believe the PM-30 board is just some muting circuitry and an inverter to send a balanced signal to the TPA power amp IC.

 

[CR0SSBL4DE]

Aren't these amps that have the class D power stage designed by Synergy?
Apparently their response is lots better than a generic TPA power board

 

[CR0SSBL4DE]

Yeah I traced the main effect PCB and most of the PM-30 module (if I recall most of that is from the TPA datasheet).

This isn't verified, double-checked, nothing.... don't trust it.
View attachment 110171

Instresting that they didn't use a BMT tone stack on a preamp design, and they kept the distortion pedal topology.

 

[equinox]

Ok, I was able to to audit the schematic and PCB.

I missed a couple short traces, now corrected in the attached.
R33 is 22k as in the schematic, NOT 16.2k, now corrected in the attached.
C21 I forgot to label, now corrected in the attached.
I added descriptions for S1 and S2 on the PCB
I labeled Vref A and B, and VCC per schematic on the PCB

On the original schematic, I made the following correction/updates:
1. The Tight switch wasn't hooked up quite right, now corrected (see attached). Should be 33k, 55k, or 77k, not 33k, 44k, or 55k
2. Labeled the switches (Tight and Cut).
3. Labeled all test points as per PCB (TP1, TP2, etc). I need to take voltages and see what they are at all of these points.
4. Labeled diodes (1N4148)
5. Added connector designations got J14 (output to EFX Send) and J15 (power input).

Changes between the MINI and the Thermionic Deluxe (most like Channel B):

MINI versus BE DLX
1. R3 470k vs. R2B 330k
2. R2 22k vs. R3B 10k
3. U1 is TL071 vs. IC2B.1 is TL072 (why use 071 and here instead of 072)
4. 3 specific setting (Tight-33k/55k/77k) vs. Variable (Tight-4k7 to 104k7)
5. No R7B vs. R7B
6. No C4B vs. C4B
7. C11 47p vs C8B 120p
8. R16 10k vs. R13B 27k
9. 3 specific setting (Cut-19k6/35k8/50k1) vs. Variable (Cut-0 to 100k)
10. 7 Stages vs. 6 Stages
11. Treb=>Mid=>Bass=>Vol vs. Treb=>Bass=>Vol=>Mid (tonestacks and volume are different and out of order)

Based on this...the Main board only contains the preamp! I thought the FX Loop was going to be on here, but evidently not.
As J14 of the preamp board goes to the EFX Send on the Output board and from the output board to the PM-30 Input and I don't see any components in the area of the output board.....looks like this is a Passive FX Loop (we'll see)??

There is some components on the Output board, but this is off of the Power Input, so should have nothing to do with the signal line and FX loop. Will post this portion this weekend. There is also a component heat-shrunk in the switch connector I'll check but assuming some sort of inline fuse and as none appears anywhere else.

I wonder why the changes in components above and which would be better/best? Variable Tight and Cut is definitely a betterment and people can dial things in the way they want and more versatility.

I wonder why the changes to tonestack and output and additional stage and again, which would be better/best.

 

[equinox]

Attached is the Output board for reference