Aion Termina (Timmy) to Jan Ray?

[Noodles]

I'm wondering if anyone has used the Termina PCB to create a Jan Ray clone. I'm starting with that PCB rather than the Tommy as a quick look (to me) suggests it's easier to change the values to match the Jan Ray schematic.

I've compared component to component and it seems pretty straightforward. I see the Jan Ray uses a B10K for the volume pot vs an A25K with a 18K resistor in parallel (isn't that basically a 10K pot, in essence?). I'm a little unclear on the log/antilog to linear practical effect. I know the bass switches from a "subtract" to an "add" control.

Here are the changes I'm planning to make. I would appreciate any comments regarding past experience or comments on my approach.

Part	Termina Value	JR Value
C1	39n	47pF
C2	47pF	22pF
C3	100pF	47pF
C4	39n
C5	1uF
C6	10n	47n
C7	2n2	150pF
C8	1uF
C9	47uF
C10	100uF
C11	100n
R1	510k	1M
R2	3k3
R3	9k1
R4	680R
R5	1k	1k2
R6	10k	3k3
R7	10k	3k3
R8	18k
R9	8k2	7k5
R10	10k	9k1
R11	100R
RPD	2M2	1M
LEDR	4k7
D1	1N5817
D2	1N914	1N4148
D3	1N914	1N4148
D4	1N914	1N4148
D5	1N914	1N4148
D6	1N914	1N4148
IC1	LM1458	LM4558N
BASS_TRIM	10k trimmer
GAIN	A1M	B500K
BASS	C50K	B50K
TREBLE	B50K	B10K
VOLUME	A25K	B10K

 

[HamishR]

Having built both on Vero quite a few times I would merely say that the differences in use are fairly minimal and that the trimmer in the Jan Ray seems superfluous. I'd probably just as soon just use a Timmy. The Vemuram Timmy which I think really is worth building is the Ibanez/Vemuram TSV-808. I have my own version of it where I just use a simplified midrange and leave out the mid pot and clipping switches and it sounds very, very good. I doubt you could built it on a Timmy board though. You could definitely built it on PedalPCB's TSV-808 board though.

 

[Noodles]

I've had a few real Timmys. I'm doing this version just to see if I actually notice any differences...plus it amuses me to do a clone of a (mostly) clone of a great pedal. Thanks for your thoughts. I'll check out the TSV-808.

 

[Brett]

If you decide to go down this route and try to build the Jan Ray on the Termina board, the value you have for C1 should be 47nF, not 47pF.

You have R9 and R10 swapped around. R9 should be 9.1KΩ and R10 should be 7.5KΩ.

I think that the rest of the values look okay. You may consider leaving the Bass control as an anti-log "C" taper, it's supposed to feel a little more natural for bass control in this circuit topology.

The clipping section does differ slightly between the two. The Jan Ray's clipping section is equivalent to having the clipping switch in the middle (off) position.

 

[Noodles]

If you decide to go down this route and try to build the Jan Ray on the Termina board, the value you have for C1 should be 47nF, not 47pF.

You have R9 and R10 swapped around. R9 should be 9.1KΩ and R10 should be 7.5KΩ.

I think that the rest of the values look okay. You may consider leaving the Bass control as an anti-log "C" taper, it's supposed to feel a little more natural for bass control in this circuit topology.

The clipping section does differ slightly between the two. The Jan Ray's clipping section is equivalent to having the clipping switch in the middle (off) position.

Good grief - thank you so much for the corrections. I had misread the discussion on freestompboxes re: the voltage divider.

Any thoughts on the volume control? I'm thinking of just leaving it at the Termina values since I think it gets to basically the same place. OTOH, if I used the Jan Ray values, I'm not 100% clear on whether I would leave the 18K/R8 position open or whether it requires a jumper.

 

[Brett]

Any thoughts on the volume control?

R8 looks like a tapering resistor. You'd just omit it if using the stock Jan Ray value for volume (B10K). Do not jumper the pads for R8.

 

[Noodles]

Thanks