Tech21 - Character Series.  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

Re: Tech21 - Character Series.

Postby Giaime » 06 Mar 2016, 12:17

CloneME wrote:Has anyone successfully modded one of these for less noise with the drive up?


Hi, I just modded mine with TL974 opamps, even lower noise than TLC2272 and they sound just as good as the originals 8)
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Re: Tech21 - Character Series.

Postby ericlaw02 » 30 Jun 2016, 08:50

Hi there, I successfully modified my Joyo British into a VT Bass, thanks to this thread!

For anyone else who wants to attempt the same mod, I have uploaded my own pictorial reference for the part substitutions between the British/VT Bass (based on the tables from this thread). The SMD capacitors/resistors to be replaced are all 0603 (1608 metric) sized.

It sounds pretty much identical with same settings when comparing to VT Bass reviews on YouTube.

I also attempted the speaker sim bypass mod as per http://freestompboxes.org/viewtopic.php?f=1&t=13545&start=20, but the treble gain is a bit too much even when plugging into the effects return. I think I might attempt the additional 22k-?nf 6db lowpass filter (like the VT Bass V2) with an on-on-on switch later.

I also thought of adding an XLR out by nicking the BDDI's balanced out circuit, but that would mean sacrificing the ample space for the 9V battery. (also I would have to make an layout myself, because there doesn't seem to be a small enough layout that just has that part, which means more work)
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12Bass (30 Jun 2016, 10:21), deltafred (20 Jul 2016, 21:08), JiM (10 Jul 2016, 00:18)
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Re: Tech21 - Character Series.

Postby medvege » 27 Nov 2016, 12:25

Sorry for the old thread
Recently I got Bass Fly Rig, which i almost loved.
However, I play in metal band and personally like open highs.
Speaker sim in this unit is nice, but cuts all the highs above ~4kHz.
Turning higs up actually adds clank, but nothing in the air
I don't want to make speaker sim defeat, moving low pass freq will be better
I found two ways in this thread

1) bajaman's advice will be reducing R14:
R14 is reduced from 47k to 33k in the British - Only a slight difference in the high frequency rollof characteristic ( British = 4.8khz, and Blonde = 4.2khz) I guess this is the difference with the Celestion speaker response model in the British compared to the Jensen speaker response model in the Blonde 


2) Darkglass advising increasing R18:
For getting the same funcioality as the new Character pedals, I would increase the value of R18. In the Liverpool is 33k, I would try anything from 47k to 100k.


Which way do you think will be better, or may be another one? Thank you!

*guessing Bass fly rig will be another story...
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Re: Tech21 - Character Series.

Postby medvege » 08 Jun 2017, 21:45

Anyone?
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Re: Tech21 - Character Series.

Postby thehallofshields » 25 Jun 2017, 19:30

Looking at the schematics posted, I noticed that R5 is not consistent between models.
This is part of the buffer stage and forms an R-C network with C2.

Also is anyone knows what R5 is on the Joyo pedals, please share.
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Re: Tech21 - Character Series.

Postby thehallofshields » 25 Jun 2017, 20:18

thehallofshields wrote:Looking at the schematics posted, I noticed that R5 is not consistent between models.
This is part of the buffer stage and forms an R-C network with C2.

Also is anyone knows what R5 is on the Joyo pedals, please share.


R5 is likely R5 on the Joyo, but I'm not sure about the Tech21 v2. If anyone has this info, please share!
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Re: Tech21 - Character Series.

Postby karaman » 02 Jul 2017, 09:31

R5 in the SansAmps is R2 in the Joyo pedals. It is 22k in both my American and AC Tone.
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Re: Tech21 - Character Series.

Postby n4m3less » 09 Aug 2017, 08:32

bajaman wrote:I would suggest trying a value of 1n (possibly more) for the capacitor marked with a ?
This sets the high frequency rolloff when the speaker simulator cabsim switch is disengaged.
For the suggested value the high frequency response will be approximately -3db down at 8KHz.
Double the value (2n2) and the response will be -3db at 4Khz.
cheers
bajaman

Stupid question:
I have a VT bass v2 and if I would remove 6dB per octave high roll off filter when a sim Cab is disengaged just remove this cap marked with "?" ?
But this problem can also be bypassed by putting an equalizer pedal and boosting of 6db the 4.5khz?
Thanks
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Re: Tech21 - Character Series.

Postby AuditoryDriving » 19 Aug 2017, 06:48

Too bad no one seems to have the values for the Leeds and California pedals, it would be very interesting and educational.

i ll never get tired of saying those pedals are brilliant ( i have the blonde and the liverpool)!
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Re: Tech21 - Character Series.

Postby kcstratslinger » 02 Oct 2017, 18:13

Hey medvege. Did you ever find an answer or make an attempt at the R14/R18 mod? I have a Blonde that seems too dark. I would like the highs to be more extended but can't find any info anywhere.
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