EHX - Clockworks EH5385  [schematic]

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

EHX - Clockworks EH5385  [schematic]

Postby JuliaDee » 26 Mar 2011, 20:28

Hello FreeStompers. I recently unearthed a file folder of Clockworks documentation and am pleased to be able to publish the info here for your entertainment. From the file notes it looks like I had the original concept idea in 1977, but didn't get around to actually building anything until late 1980. My first attempt apparently involved non-retriggerable one-shots but that was less than satisfactory and was abandoned in favor of the analog frequency divider approach that ultimately went into the product.

I've designed literally hundreds of products that have gone into production over the past 35 years, but I think this may be the one of which I'm most proud, both for what it does and how it does it.

I'm attaching both the (redrawn, as my originals were a bit marked up and confusing) schematic and a scan of the original instruction booklet. I also have a somewhat ratty photocopy of the (single-sided) PCB layout if anyone's interested.

One aspect of the rig that can be viewed as either a drawback or a feature is that being entirely analog, you can't save your settings. And believe me, the permutations are so vast that you'll never get the same thing twice, so keep your recording equipment running. In a way, this makes it a more "pure" performance instrument, but at times you really will wish you could save a particularly awesome patch. It's long been a fantasy of mine to realize the whole system in the digital domain, but time has never permitted. I did spend a month or so during a dry spell about three years ago trying to implement it in desktop software, but the SDK I was using wasn't good at real-time timekeeping. I think maybe a dedicated embedded solution for self-containedness as a performance instrument, with remote desktop configuration and patch management via USB might be the hot ticket.

There's lots of room for UI improvement of course. I was constrained by the E-H sheet metal box and the 10 sliders inherited from the original Graphic EQ, and they are surprisingly playable, but with a free palette of touch controls, gesture sensing etc. you could certainly make it much cooler.

I'll be happy to answer any questions anyone might have.

Thanks to fsb member inlifeindeath for motivating me to get this documentation together.

julia

Clockworks Schematic.pdf
You do not have the required permissions to view the files attached to this post.

For this message the author JuliaDee has received thanks: 28
culturejam (18 Nov 2011, 15:53), DiscoFreq (04 Dec 2012, 22:41), e45tg4t3 (28 Mar 2011, 10:59), jrjoe21 (26 Mar 2011, 20:33), modman (27 Mar 2011, 15:27), mouse (11 Jun 2011, 12:52), raindog (16 Oct 2011, 15:43), RnFR (27 Mar 2011, 16:18), salocin (27 Mar 2011, 01:26), toneman (06 Mar 2013, 02:26) and 18 more users
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby RnFR » 26 Mar 2011, 20:40

very cool! thanks a lot, Julia. we at fsb are honored by this look into the past. you definitely don't get to see something like this every day!

edit- the PDF appears to be blank? are you sure it was properly uploaded?
"You've converted me to Cubic thinking. Where do I sign up for the newsletter? I need to learn more about how I can break free from ONEism Death Math." - Soulsonic

Blog-APOCALYPSE AUDIO
User avatar
RnFR
Old Solderhand
 
Posts: 5136
Joined: 09 Jan 2008, 07:02
Location: Inner Earth
Has thanked: 138 times
Have thanks: 170 times

Re: EHX EH5385 Clockworks

Postby Scruffie » 26 Mar 2011, 20:44

Wow :shock: This is amazing! Thank you so much Julia.

I'd certainly love to see the PCB layout you have aswell, I always wondered, did EHX outsource its PCB designs or were they done by the designers themselves? They're all so amazingly symmetrical and well laid out.

Thank you again for providing this information, hopefully some revived units and interest will come of it!
Scruffie
Opamp Operator
 
Posts: 1727
Joined: 13 Mar 2009, 18:59
Location: London.. ish, Uk
Has thanked: 27 times
Have thanks: 136 times

Re: EHX EH5385 Clockworks

Postby Scruffie » 26 Mar 2011, 20:46

RnFR wrote:very cool! thanks a lot, Julia. we at fsb are honored by this look into the past. you definitely don't get to see something like this every day!

edit- the PDF appears to be blank? are you sure it was properly uploaded?


PDFs loaded fine for me.
Scruffie
Opamp Operator
 
Posts: 1727
Joined: 13 Mar 2009, 18:59
Location: London.. ish, Uk
Has thanked: 27 times
Have thanks: 136 times

Re: EHX EH5385 Clockworks

Postby Greenmachine » 26 Mar 2011, 20:53

Thanks Julia!
"[Y]ou want sketchy, dude? I breadboard on a door." -- RnFR, 2011
"This amp is freakin loud, like crazy, I'm going to kill pets loud." -- mich, 2011
User avatar
Greenmachine
Cap Cooler
 
Posts: 621
Joined: 31 Aug 2008, 18:59
Location: Jersey City, NJ
Has thanked: 102 times
Have thanks: 19 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 26 Mar 2011, 21:15

OK, I'll scan the PCB layout asap. We had an in-house PCB layout guy at E-H, a wonderful man named Harry Fliegelman. I think the designers sometimes grabbed tape and mylar themselves if Harry was overloaded.

julia

Scruffie wrote:Wow :shock: This is amazing! Thank you so much Julia.

I'd certainly love to see the PCB layout you have aswell, I always wondered, did EHX outsource its PCB designs or were they done by the designers themselves? They're all so amazingly symmetrical and well laid out.

Thank you again for providing this information, hopefully some revived units and interest will come of it!
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 26 Mar 2011, 21:20

Oops, I meant to attach a photo of the gizmo as well, for those who've never seen one...

Screen shot 2011-03-24 at 9.58.54 PM.png
You do not have the required permissions to view the files attached to this post.

For this message the author JuliaDee has received thanks:
toneman (06 Mar 2013, 02:27)
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby roseblood11 » 26 Mar 2011, 23:10

...what about those who´ve never listened to one? :D
roseblood11
Opamp Operator
 
Posts: 1692
Joined: 23 Aug 2008, 15:21
Has thanked: 322 times
Have thanks: 299 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 26 Mar 2011, 23:13

roseblood11 wrote:...what about those who´ve never listened to one? :D


Um... I've got some stuff on 4-track reel-to-reel but sold my deck years ago, lol.
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby Scruffie » 26 Mar 2011, 23:15

roseblood11 wrote:...what about those who´ve never listened to one? :D

They go to youtube :) http://www.youtube.com/watch?v=hguuj9sZvDk about the only demo about for it... sadly not all that wonderful.

It's not something you really listen to though, it's a trigger you'd use with the other EHX Synth/Drum Products from what I gather.
Scruffie
Opamp Operator
 
Posts: 1727
Joined: 13 Mar 2009, 18:59
Location: London.. ish, Uk
Has thanked: 27 times
Have thanks: 136 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 26 Mar 2011, 23:23

Scruffie wrote:
roseblood11 wrote:...what about those who´ve never listened to one? :D

They go to youtube :) http://www.youtube.com/watch?v=hguuj9sZvDk about the only demo about for it... sadly not all that wonderful.

It's not something you really listen to though, it's a trigger you'd use with the other EHX Synth/Drum Products from what I gather.


Yeah, not a great demo on YouTube. You're correct - it has no audio output, just triggers. It was designed at the time for the other E-H percussion devices as you surmise, but it should work with just about anything that has a trigger input.
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby Hides-His-Eyes » 27 Mar 2011, 12:01

You did all that with OPAMPS?

:block: Now I can see why you're so proud of it!

I assume LM324 would be a good op-amp alternative; this seems like the perfect thing to develop as a three-board setup so you can have 2,4,6... channels depending on what case you can get hold of...

Is the op-amp setup doing things that might be done with 4000 CMOS these days, or does the op-amp setup allow the permutation subtlety?

I need some triggerable drum circuits, I think a drum machine with this as a core might be my summer project :)
Testing, testing, won too fwee
User avatar
Hides-His-Eyes
Tube Twister
 
Posts: 2015
Joined: 02 Feb 2010, 13:34
Has thanked: 53 times
Have thanks: 84 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 27 Mar 2011, 14:15

Hides-His-Eyes wrote:You did all that with OPAMPS?

:block: Now I can see why you're so proud of it!

I assume LM324 would be a good op-amp alternative; this seems like the perfect thing to develop as a three-board setup so you can have 2,4,6... channels depending on what case you can get hold of...

Is the op-amp setup doing things that might be done with 4000 CMOS these days, or does the op-amp setup allow the permutation subtlety?

I need some triggerable drum circuits, I think a drum machine with this as a core might be my summer project :)


The LM339's are quad comparators, not op-amps per se. It also comes in duals and singles; I forget the numbers right now. They have open-collector outputs, which are necessary for resetting the charge pump cap without using an additional transistor, and being comparators they're optimized for fast switching. The LM324 would probably not work nearly as well (lousy slew rate) and would require an external transistor for discharging the 5UF charge pump cap. LM339's are common and cheap.

Although it is possible to make analog comparators with 4000 series CMOS it probably wouldn't work as well as real comparators and would not be worth the bother. Or maybe you meant using 4000 CMOS in a digital approach - well that'd be a whole different kettle of fish. If you're going digital you'd be much better off using a microcontroller imo. And yes, a lot of the Clockworks' magic comes from its analog-ness - you can get the divisors on the hairy edge where they sometimes divide by one number and other times by the number just adjacent to it. There's probably crosstalk and other analog "imperfections" that contribute to its organic-ness. You could conceivably simulate this randomness in a digital implementation as well, but it'd be a big project. The best place to start might be building the original (which should take only an hour or so on a protoboard) to get a feel for what it does and then decide where you want to go from there.

I hope you do build it, and good luck!

julia
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby Hides-His-Eyes » 27 Mar 2011, 15:51

There's a guy here in the UK who makes a 'tap-tempo' LFO IC that would offer a square signal at 1-4x a frequency made by closing a switch; I think that might be a good way to bring the design into the 21st century while still keeping the quirkiness of the dividers. I'll stick some comparators in my next order and give it a go with that. :)
Testing, testing, won too fwee
User avatar
Hides-His-Eyes
Tube Twister
 
Posts: 2015
Joined: 02 Feb 2010, 13:34
Has thanked: 53 times
Have thanks: 84 times

Re: EHX EH5385 Clockworks

Postby Hides-His-Eyes » 27 Mar 2011, 16:42

Do you think it would run on 9V? Depending on what I can find for drum circuits I might have to use a charge pump already for making a bipolar supply (when synth circuits are written for +-15, I always figure it's not worth converting to virtual ground if that would only leave the circuit with +-4.5V!) and I wouldn't want two of the things heterodyning.
Testing, testing, won too fwee
User avatar
Hides-His-Eyes
Tube Twister
 
Posts: 2015
Joined: 02 Feb 2010, 13:34
Has thanked: 53 times
Have thanks: 84 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 27 Mar 2011, 17:51

Hides-His-Eyes wrote:Do you think it would run on 9V? Depending on what I can find for drum circuits I might have to use a charge pump already for making a bipolar supply (when synth circuits are written for +-15, I always figure it's not worth converting to virtual ground if that would only leave the circuit with +-4.5V!) and I wouldn't want two of the things heterodyning.


You could try it on 9V; there will just be that much less error/noise margin for the frequency dividers. The staircase steps in the dividers are about 1/15 of the supply voltage (1UF÷15UF), so at 9V they'd only be about 600mV each. Capacitor droop on the staircase steps on the 15UF caps could become an issue, as might the 741's output swing.

I think it takes a fair amount of current since it's constantly pumping those four 1UF caps (and the LEDs) so a charge-pump based power supply may not be the best approach. Better to make a real ±15V supply and then regulate down from that with linear or switching regulators if you have stuff that absolutely must run at lower voltages.
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby Hides-His-Eyes » 27 Mar 2011, 19:58

Could you use a 10uF there instead and use a smaller trimmer accordingly to still get the 8 steps? 15u 10% is not a common value; mouser have it but otherwise I'd have to stack a 10 and a 4.7. Not the end of the world but if the 10u might work better with the 9V supply it might be worth it.
Testing, testing, won too fwee
User avatar
Hides-His-Eyes
Tube Twister
 
Posts: 2015
Joined: 02 Feb 2010, 13:34
Has thanked: 53 times
Have thanks: 84 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 27 Mar 2011, 20:14

Hides-His-Eyes wrote:Could you use a 10uF there instead and use a smaller trimmer accordingly to still get the 8 steps? 15u 10% is not a common value; mouser have it but otherwise I'd have to stack a 10 and a 4.7. Not the end of the world but if the 10u might work better with the 9V supply it might be worth it.


The staircase step size = clock voltage * input cap / storage cap. So with the original values you have

    ≈15V clock swing * 1UF/15UF = 1V per step.

The tradeoffs are:

    A smaller step makes everything more critical - noise, crosstalk, cap leakage, trimmer sensitivity, etc. You want the steps as large as possible while still being able to achieve the maximum desired divisor, i.e. 8.
    A bigger input cap means more load on the clock and more supply current.
    A smaller storage cap means more sensitivity to leakage currents.

I'm sure there's room to play around with the values some, you'll just have to fiddle with it. That's what protoboards are for :-)

For this message the author JuliaDee has received thanks:
Hides-His-Eyes (27 Mar 2011, 20:45)
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Re: EHX EH5385 Clockworks

Postby e45tg4t3 » 14 Oct 2011, 17:18

Hi There Guys and Girls,
At the moment i´m trying to route a layout for the Clockworks, but came across a little strange piece in the schematic... so are the connections from the base´s of the two power transistors(2n6111/2n6290) to the Supply Pins of the 741 correct? Just seems a little strange to my eyes...

Best Regards

Ben
e45tg4t3
 
Posts: 20
Joined: 26 Jun 2007, 18:25
Location: Heubach/BW/Germany
Has thanked: 12 times
Have thanks: 2 times

Re: EHX EH5385 Clockworks

Postby JuliaDee » 14 Oct 2011, 17:36

Yes, the schematic I posted here is correct. For another example of this type of op-amp output booster see Walt Jung's IC Op-Amp Cookbook fig 6-25. It's on page 311 of my 1976 edition...

Julia

e45tg4t3 wrote:Hi There Guys and Girls,
At the moment i´m trying to route a layout for the Clockworks, but came across a little strange piece in the schematic... so are the connections from the base´s of the two power transistors(2n6111/2n6290) to the Supply Pins of the 741 correct? Just seems a little strange to my eyes...

Best Regards

Ben

For this message the author JuliaDee has received thanks: 3
e45tg4t3 (14 Oct 2011, 17:57), Hides-His-Eyes (19 Nov 2011, 02:04), theehman (14 Oct 2011, 18:29)
User avatar
JuliaDee
 
Posts: 27
Joined: 18 Feb 2011, 18:51
Location: Connecticut
Has thanked: 3 times
Have thanks: 89 times

Next

Return to Modern Stompbox Effects (1975 - ...)

Who is online

Users browsing this forum: elitem and 11 guests