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Lehle - Sunday Driver

Posted: 21 Mar 2017, 10:09
by kusi
hello my friends,

long time no see, i hope everyone is still alive and doing great? :D

i just spent some minutes tracing the lehle sunday driver, a great sounding buffer / booster which i use in the studio all the time to track guitar di's (instead of the interface/preamp hi-z in).
nothing too special. the power-supply is a bit strange, it's not the best idea to power a 9v linear regulator with 7,5V imho. also the bias-offset of 0,125V, not sure if it's really worth the effort.

let me know what you think!

cheers,
kusi

Re: Lehle Sunday Driver [schematic]

Posted: 21 Mar 2017, 13:55
by zoetrop
Thanks, I really like your schematic and thanks for your effort! could you please double-check R4, in the photo it looks like 4k7 instead of 47k (which would lead to a ~ 1.58 V bias)?

Re: Lehle Sunday Driver [schematic]

Posted: 21 Mar 2017, 15:47
by kusi
thanks! r4 is 47k, voltage of 0,125V is measured. someone posted the schematic of Lehles paralell pedal here, the small bias-offset is similar.
viewtopic.php?f=1&t=27364&hilit=lehle

Re: Lehle Sunday Driver [schematic]

Posted: 25 Mar 2017, 11:22
by apollomusicservice
C2=100n
C6=10u
C12=1n
C13=120p
C14=330p
C15=15p
30-50mA current consumption

Re: Lehle Sunday Driver [schematic]

Posted: 27 Mar 2017, 01:27
by x-tn
kusi wrote:...the power-supply is a bit strange, it's not the best idea to power a 9v linear regulator with 7,5V imho...
Your schematic says "all voltaged measured with 9Vdc power supply."
It looks like it requires AC power. With AC power you would have higher than 7,5V at the regulator input.

Re: Lehle Sunday Driver [schematic]

Posted: 27 Mar 2017, 06:07
by kusi
x-tn wrote:
kusi wrote:...the power-supply is a bit strange, it's not the best idea to power a 9v linear regulator with 7,5V imho...
Your schematic says "all voltaged measured with 9Vdc power supply."
It looks like it requires AC power. With AC power you would have higher than 7,5V at the regulator input.
of course 9vac would make more sense. but the manual clearly states 9V ac OR DC.


thanks apollomusicservice for the values!

Re: Lehle Sunday Driver [schematic]

Posted: 27 Mar 2017, 20:59
by apollomusicservice
kusi wrote: thanks apollomusicservice for the values!
No problem, I just checked values on my pedal.

Re: Lehle Sunday Driver [schematic]  [schematic]

Posted: 28 Mar 2017, 05:15
by kusi
updated schematic w. cap-values:

Re: Lehle Sunday Driver [schematic]

Posted: 30 Mar 2017, 05:49
by apollomusicservice
C15=15p

Re: Lehle Sunday Driver [schematic]

Posted: 03 Apr 2017, 05:42
by kusi
is c15 fitted in your version? because in mine it's not (but it doesent really matter if it's 15pF).

thanks for checking!

Re: Lehle Sunday Driver [schematic]

Posted: 03 Apr 2017, 08:00
by apollomusicservice
kusi wrote:is c15 fitted in your version? because in mine it's not (but it doesent really matter if it's 15pF).

thanks for checking!

Under the S/D switch.

Re: Lehle Sunday Driver

Posted: 08 May 2017, 14:31
by Cub
Quite the power filtering! Almost seems overkill, but that's probably why I'm painting by numbers and the good people at Lehle are designing and building these things to put bread on the table.
Please forgive me if this sounds dumb, but would this filtering be helpful in a Big Muff circuit or an Overdrive / Clean boost to keep the noise down?

Re: Lehle Sunday Driver

Posted: 08 May 2017, 15:01
by FiveseveN
would this filtering be helpful in a Big Muff circuit or an Overdrive / Clean boost to keep the noise down?
Discrete designs like the more popular Big Muffs have poorer PSRR than something like this, so sure. But what exactly do you mean by "this filtering"? There's a rectifier, smoothing cap(s) and a regulator. Your PSU should already be regulated, but Lehle might not want to take that chance, and that's what the solution is about: flexibility and protection. You can feed it a wide range of voltages with either polarity or even AC and it will work just fine. Interestingly, the "standard" user case where you'd feed it with a proper 9V DC PSU is not the ideal condition, as the others have mentioned above.

Re: Lehle Sunday Driver

Posted: 08 May 2017, 16:32
by Cub
Thank you for your explanation, always eager to learn.

Lehle - Sunday Driver SW (Gut Shots)

Posted: 30 Jul 2017, 18:13
by hasanova
Here are some gut shots of a Lehle Sunday Driver SW (it says "Sunday Driver L v1.0" on the PCB). The version without an on/off switch is already traced. One more difference: this one has the TS (True Sound) and TB (True Bypass) switching.

Re: Lehle - Sunday Driver SW (Gut Shots)

Posted: 30 Jul 2017, 18:16
by hasanova
One more pic

Re: Lehle - Sunday Driver SW (Gut Shots)

Posted: 30 Jul 2017, 18:20
by hasanova
The other side

Re: Lehle - Sunday Driver SW (Gut Shots)

Posted: 30 Jul 2017, 19:13
by hasanova
With some parts values...

Re: Lehle Sunday Driver

Posted: 22 Mar 2019, 15:52
by blacky
Did anyone try the build on this schematic yet?

Re: Lehle - Sunday Driver

Posted: 11 Mar 2022, 19:56
by gsb
Hi,
I want to try build one for friend -for electric guitar .My question is any options for another ic,s -LM4562 ? or AD823 IC,s.? Newer version work with higher voltage evt. +- 15V to try .
Thanks for help
gsb