I traced each diode in the circuit and compared the read traces with reference diode traces.
So I found out as follows.
Ge-diodes are 1N34A green band.
Big Si-diodes are 1N4005.
Small Si-diodes are 1N4148
Re: Rockett Flexdrive dissected
Posted: 12 Jul 2016, 22:48
by 287m
hello manfred
the switch :
fat = spst
clip = on-on or on-off-on?
treble = on-on or on-off-on?
and the 1n4001 look backward for me
Re: Rockett Flexdrive dissected
Posted: 13 Jul 2016, 06:15
by Manfred
Hello 287m,
thanks for finding the fault.
and the 1n4001 look backward for me
You are right, the 1N4001 is drawn in wrong orientation, here the corrected schematic.
fat = spst
clip = on-on or on-off-on?
treble = on-on or on-off-on?
Fat: off on.
Clip: on off on.
Treble on off on
I read the datas of the built-in J201:
Vgs(off)=-0,72V at Id=5,2µA
Vgs(on)=0,38V at Id=1,26mA
gfs=1,9mA/V at Id=0,8mA to 1,3mA
Idss=0,58mA at Vds=3,01V
Rds(on)=549,1O at Id=1,3mA and Vgs=0,0V
Re: Rockett Flexdrive dissected
Posted: 13 Jul 2016, 07:33
by tube-exorcist
I bet the tone control is drawn wrong too and should look like one from a tube-screamer - please verify.
Re: Rockett Flexdrive dissected
Posted: 13 Jul 2016, 19:39
by Manfred
tube-exorcist wrote:I bet the tone control is drawn wrong too and should look like one from a tube-screamer - please verify.
Sorry, I cannot verify the pedal again, because I gave it already away.
It was very hard to trace, but I used the tube screamer circuit as pattern and it was not in accordance with the screamer tone control, that amazed me.
The Flexdrive tone control affects nut much in my opinion, it acts rather as treble lift when the knob is turned clockwise.
have a look at
Tone knob variations at the playing time from 3:38 to 3:45.
I think that explains the different tone circuity.
I'm not without fail, maybe a owner of the Flecdrive would be so kind to recheck the tone circuit.
Re: Rockett Flexdrive dissected
Posted: 14 Jul 2016, 19:20
by Manfred
tube-exorcist wrote:I bet the tone control is drawn wrong too and should look like one from a tube-screamer - please verify.
hi,
I thougt about the circuit differences and made a circuit simulation.
The shown tone circuity has indeed no effect.
You are right regardíng the screamer tone circuity.
Thanks that you took a closer look at the schematic.
Re: Rockett Flexdrive dissected
Posted: 15 Jul 2016, 06:53
by tube-exorcist
Now there is only missing a 22k resistor (maybe 2k2) between pin 6 and 7 of the second opamp (instead of the short).
Re: Rockett Flexdrive dissected
Posted: 15 Jul 2016, 12:03
by Manfred
tube-exorcist wrote:Now there is only missing a 22k resistor (maybe 2k2) between pin 6 and 7 of the second opamp (instead of the short).
The short is ok, there is no resistor in between.
Re: Rockett Flexdrive dissected
Posted: 13 Feb 2018, 01:56
by himers
Where are the two Capacitors 22n(223) connected？
I understand that one is treble, but one after the other?
Those who know, please tell me
Re: Rockett Flexdrive dissected
Posted: 27 Feb 2018, 00:10
by indyguitarist
Manfred wrote:
tube-exorcist wrote:I bet the tone control is drawn wrong too and should look like one from a tube-screamer - please verify.
hi,
I thougt about the circuit differences and made a circuit simulation.
The shown tone circuity has indeed no effect.
You are right regardíng the screamer tone circuity.
Thanks that you took a closer look at the schematic.
FlexDriveCorrected2.JPG
No, actually it isn't the TS tone control. you had it right the first time I think. 5k pot across pins 6/7, middle lug goes to a 100r and .022uf IIRC.
It's been about 10 years since I drew that though so.....
