Crowther Audio - Hot Cake Overdrive

briggs · Post by **briggs** » 15 Jul 2007, 15:37

I think it is used to reduce the voltage down from 9v to 8.2v so I guess you can't sub it out.

jt · Post by jt » 15 Jul 2007, 16:13

Thanks briggs

bajaman · Post by **bajaman** » 15 Jul 2007, 21:39

It is there for protection - in case some clown plugs in a higher voltage supply - they are out there - trust me on this one folks

It then clamps the dc voltage to 8.2 volts and provides stable operation from the circuit

Cheers
Steve

JHS · Post by **JHS** » 16 Jul 2007, 09:40

The schem is an older version w buffered bypass.

The HC was slightly altered over the years (I know at least 8 different versions w true and buffered bypass).

This version sounds very good, but maybe, depending on the trannie HFE, the values of the Zener diode must be slightly altered (+/- 25%) to get it sound right.

I prefer the new tone pot version, 'cos it can produce all inbetween sounds ( w the pot fully closed and fully opened you'll get the 2 sounds of the switch version).

JHS

bajaman · Post by **bajaman** » 16 Jul 2007, 09:43

Hi JHS
Yes - but the old ones sounded more warmer to my ears because of the 741 and it's lousy high end response - sometimes good top end is not necessary, especially in distortion devices

cheers
Steve

briggs · Post by **briggs** » 16 Jul 2007, 09:43

I agree, I used Torchy's layout and it sounded great. More versatile than the switch version.

bajaman · Post by **bajaman** » 16 Jul 2007, 09:45

Try an NE5534 or OPA134 instead of the TL071

analogguru · Post by **analogguru** » 17 Jul 2007, 10:25

Interesting:
Crowther Hotcake XLF Bass
http://1484.bz/shinjuku/select.cgi?id=18001

analogguru

bajaman · Post by **bajaman** » 17 Jul 2007, 11:47

XLF - extra low frequency - probably increased the feedback and coupling caps - BTW, it's the green led that gives it that Ka ching sound

Cheers
Steve

bluetoad · Post by **bluetoad** » 17 Jul 2007, 21:50

Just built this per the Torchy layout. Thanks man, turned out great. Tried out a bunch of different opamps as well; TL071 is the best to my ears, but the 741 is harsher in a nice way. A little more compressed, I think. The two sounded pretty good in parallel, but not good enough that I thought it was worth the headache.
Carl

bajaman · Post by **bajaman** » 17 Jul 2007, 22:01

Hi bluetoad
Did you connect the additional 220k resistor from the inverting input (op amp pin 2) to the half rail voltage point, when trying the 741

Try it
Cheers
Steve

soulsonic · Post by **soulsonic** » 17 Jul 2007, 22:26

I wonder what an LF411 would sound like in it? I guess I have to build one now too.

Mayniac · Post by **Mayniac** » 26 Jul 2007, 20:54

Does the value of the zener diode have an influence on the sound? The schematic lists two different values: 8.2 or 8.7 Volt. Does it make a difference?

Goop_buster · Post by **Goop_buster** » 26 Jul 2007, 21:13

I only had a TL072 (half from) when I tried this out according to one of the older schematic.
I expected to hate it

but when I plugged it in I could not believe how good a single OP-amp could clip

.

Nice circuit. Well worth the effort to try out and experiment with

jt · Post by jt » 26 Jul 2007, 21:18

Does anyone know the differences between this and the bluesberry version?

markm · Post by **markm** » 27 Jul 2007, 14:42

jt wrote:Does anyone know the differences between this and the bluesberry version?

I think it's mellower....no?

bajaman · Post by **bajaman** » 27 Jul 2007, 23:13

Come in Bluesberry degooper

JHS · Post by **JHS** » 28 Jul 2007, 09:09

The Bluesberry has a bit more treble, so I think 1 or 2 cap values had been altered. The difference between those two is very subtle.

JHS

bajaman · Post by **bajaman** » 28 Jul 2007, 10:50

Probably the 10k, 82n and 1k
try different values here for different responses

bajaman

Post by **modman** » 28 Jul 2007, 19:12

Building this now and only have a 8.2V zener or a 9.1V, check the datasheet for the original 1N5238 and it says 8.6V. AG's schematic give an alternative zener which IS 8.2V so I guess this is ok.

I read this thread with some great comments by JHS, but it doesn't tell me much about which value of zener and why.

https://www.diystompboxes.com/smfforum/ ... ic=50807.0

Maybe JHS could you replace that dead link?

thanks

Crowther Audio - Hot Cake Overdrive [traced]