my sneaky rockit plan...

[denden]

After getting my 130 superlead back from clarry (200 Watts peak!) i found out an interesting bit of information.

Apparently after tracing the boost circut in the rockit, its practically identicall to the '77 crowther hotcake. Heres the thing, i have a 2003 hotcake in my pedal board, and would like to cascade two of them. So i was planning on finding out if its possible to convert the '77 model to the 2003. The main difference i believe is in the chip, but some of the other componentry may need to be swapped out. I was hopin' those with more knowlege on the subject may be able to shed some insight on the idea

[denden]

Schematics for both hotcakes

[Ears]

Sorry can't answer your question but have some of my own.
What's the flip flop for in the 2003 version? How is it triggered? I'm a bit rusty on digital stuff, can someone run me through it. The point labeled Rel1 seems too be tied to ground, or is two ports and sensing the potential between ground and C8? Is that the trigger port (switched by S1)

[ash]

If by flip flop you mean Rel1, its a relay switching the "bypass" and the LED. S1 is the footswitch which turns on Rel1, thus switching Rel1a and Rel1b into the positions shown, turning on the LED and shifting the gain of the Opamp into boost/distortion territory.

Its a pretty strange way to bypass the pedal as it isn't bypassing anything at all. Just switching from unity gain to a higher gain state. So if the battery dies, it shuts everything off and you have to unplug it rather than just switching it off.

[ash]

So i was planning on finding out if its possible to convert the '77 model to the 2003. The main difference i believe is in the chip, but some of the other componentry may need to be swapped out.

Why do you need it to be 2003 spec to cascade them?

The magic in a real Hotcake is in the exact charachteristics of certain components that Crowther selects for the job. Slew rate of the op-amp for example. You could mess with the on-board boost or make up a little Hotcake clone on perfboard (its a pretty simple circuit) but without knowing what specs make a hotcake do what it does, its a bit of a lottery.

I don't think that changing the on-board boost is going to help you much. Most of the difference between the two is in how its turned on and off and the LED indicator.

[Ears]

If by flip flop you mean Rel1, its a relay switching the "bypass" and the LED. S1 is the footswitch which turns on Rel1, thus switching Rel1a and Rel1b into the positions shown, turning on the LED and shifting the gain of the Opamp into boost/distortion territory.

Its a pretty strange way to bypass the pedal as it isn't bypassing anything at all. Just switching from unity gain to a higher gain state. So if the battery dies, it shuts everything off and you have to unplug it rather than just switching it off.

Ta, yes, the relay assembly descibed as bistable (latch) = a flip flop, I am unfamiliar with the symbol next to (left of) Rel1, although it rings vague bells, I take it from your explanation it is the relay coil then, connected to both C8 and ground. To further expose my possible/probable ignorance, what's the E mean in R1's 220E ?
Don't quite follow your point about about specs though, as the op amp is specified and a look inside any unit will inform on capacitor choice and resistance tolerance. What/which is/are the critical componentry?
Am I right that these have a good reputation as a compressor as well as overdrive function.

[ash]

Ta, yes, the relay assembly descibed as bistable (latch) = a flip flop, I am unfamiliar with the symbol next to (left of) Rel1, although it rings vague bells, I take it from your explanation it is the relay coil then, connected to both C8 and ground. To further expose my possible/probable ignorance, what's the E mean in R1's 220E ?
Don't quite follow your point about about specs though, as the op amp is specified and a look inside any unit will inform on capacitor choice and resistance tolerance. What/which is/are the critical componentry?
Am I right that these have a good reputation as a compressor as well as overdrive function.

The symbol is for the relay coil or the equivalent pin(s) on the latch.

When Paul Crowther was using 741 Op-amps ( a really low grade, old fashioned unit) I understand he was buying loads of them, testing and selecting the ones the met certain specs. One of the things was slew rate, which is particularly bad on 741s. Getting slew rate in the right range (somewhere between shitty and rubbish) is apparently one of the keys to the Hotcake sound. He would also have been selecting resistors to control the gain profile and the difference between on and "off", being that its not actually bypassed. These are things I heard from another local amp/pedal tech when he gave me a schematic some years ago.

I think 220E probably means 200 Ohms. Maybe its a German thing...

[robnobcorncob]

Ta, yes, the relay assembly descibed as bistable (latch) = a flip flop, I am unfamiliar with the symbol next to (left of) Rel1, although it rings vague bells, I take it from your explanation it is the relay coil then, connected to both C8 and ground. To further expose my possible/probable ignorance, what's the E mean in R1's 220E ?
Don't quite follow your point about about specs though, as the op amp is specified and a look inside any unit will inform on capacitor choice and resistance tolerance. What/which is/are the critical componentry?
Am I right that these have a good reputation as a compressor as well as overdrive function.

The symbol is for the relay coil or the equivalent pin(s) on the latch.

When Paul Crowther was using 741 Op-amps ( a really low grade, old fashioned unit) I understand he was buying loads of them, testing and selecting the ones the met certain specs. One of the things was slew rate, which is particularly bad on 741s. Getting slew rate in the right range (somewhere between shitty and rubbish) is apparently one of the keys to the Hotcake sound. He would also have been selecting resistors to control the gain profile and the difference between on and "off", being that its not actually bypassed. These are things I heard from another local amp/pedal tech when he gave me a schematic some years ago.

I think 220E probably means 200 Ohms. Maybe its a German thing...

So are the current Hotcakes true bypass or are they the same as stated above?

[Ears]

As Ash says, not bypassed. If anything you might consider it acts as a buffer, but it will always shape the tone through the action of caps 3,4,5,6

[zdali]

220H does in fact mean 220 Ohms

[zdali]

First thing to do would be swap out the 741 opamp with 071 which is designed as a drop in replacement and see how that sounds. Should be simple affair once you solder in the IC sockets. The rest of the difference is, like Ash says, LED and signal path switching and additional presence control. Thats definitely not a true bypass which is not necessarily a bad thing but it may explain why your hotcake is fussy on where on your pedal board it lives.

[dc]

After getting my 130 superlead back from clarry (200 Watts RMS!) i found out an interesting bit of information.

Interesting. Mine's putting out 120-odd.

[denden]

After getting my 130 superlead back from clarry (200 Watts RMS!) i found out an interesting bit of information.

Interesting. Mine's putting out 120-odd.

mines doing 100 watt clean, 200 watt peak on full power
70 watt clean, 130 watt peak on half power.

[bender]

Would either of you fullahs like the matching footswitch for that amp? I have the dedicated one from when I owned a super lead 130 and don't need it.

PM me if you want it.