freestompboxes.org

I'm posting this here for the benefit of the community. It's my own idea of what a Rockman headphone amp should be like, made with modern, easily available components. It is intentionally not an exact clone of any specific Rockman model, because my aim right from the beginning was to make it better. I'd say it's closest to an X100 without the Echo part, but with a nice feature from the Soloist (the Doubler mode), and another really nice feature from the Ace series: single 9V battery power. I also completely replaced the mixer and headphone amp section with my own design, which is much more Hi-Fi while consuming less power.

Enjoy.

Great job, JTEX !!!

Great work, nice build.

Thank You!

awesome work

Wow

I keep making small changes to the design. I won't list them all here, as it's too much maintenance. The latest revision can be found on my blog:
http://jtex.ca/2021/05/06/shockman/

Greetings,

Fantastic project JTEX! I'd like to build one if anyone might be making thru hole PCs available. If not, I may build up in sections; just the distortion amp and compressor for example. Thanks again for the great effort!

Any sound examples?

Regards, Jim

In case anyone's interested, I finally came up with a suitable delay section to go with my Shockman. There was no way I was going to just duplicate the complicated and underwhelming-sounding original ECHO circuit.

My delay uses a PT2399 chip. Its best feature is that draws only 3mA from 9v, which might just make it the world's lowest-power guitar delay. Ask me how that's even possible, since a PT2399 nominally draws about 20mA from 5V

Here's a quick demo:

Mr Jtex, how you did undervolt that baby? Beautiful!

JTEX wrote: ↑06 Mar 2022, 05:33 In case anyone's interested, I finally came up with a suitable delay section to go with my Shockman. There was no way I was going to just duplicate the complicated and underwhelming-sounding original ECHO circuit.

My delay uses a PT2399 chip. Its best feature is that draws only 3mA from 9v, which might just make it the world's lowest-power guitar delay. Ask me how that's even possible, since a PT2399 nominally draws about 20mA from 5V

Here's a quick demo:

awesome work ,share

@rcustoms: Its on his homepage: https://www.jtex.ca/

This is the current version I have in my guitar beside the Shockman, as of now. Draws 3mA from 9V. Still subject to minor tweaks, until I lose interest

BTW, that MAX17550 chip is tiny. I could barely solder it under a microscope. Worth the hassle, though -- it's very efficient with light loads, unlike most other step-down converters I considered. Most of the usual suspects are pretty inefficient when driving less than a few tens of mA (might as well use a linear regulator...).

P.S. I should mention that this delay is wet-only. The dry input signal is not mixed into the output. Shockman takes care of that, with its mixer.

Also, at 3V, you're significantly undervolting the PT2399. Worked fine for me with the 3 chips I tried, but YMMV. If your chip won't cooperate, raise the voltage at the expense of battery life.

Holy shit, dude! That's awesome.

Hey man, made a PCB based on the schematic and it does sound fantastic

But I got just one tiny issue

How can I get more volume out of this?

I should note that I used an LM741 for the first opamp instead of a TL061 and NE5532s instead of TL072 for the headphone amp stage

Reachahighernoon wrote: ↑18 May 2022, 10:43 Hey man, made a PCB based on the schematic and it does sound fantastic

But I got just one tiny issue

How can I get more volume out of this?

I should note that I used an LM741 for the first opamp instead of a TL061 and NE5532s instead of TL072 for the headphone amp stage

Sorry, belated reply. 741? I haven't seen one of those since I was about 18 or so (I'm 50 now). First op amp I've ever used. It's a very noisy chip by current standards. Also, not sure where you saw a TL061 or 072 in my schematic. Many op amps will work fine in the Shockman circuit, but I picked specific parts for specific reasons, mostly lownnoise and low power draw.

287m wrote: ↑06 Mar 2022, 23:55 Mr Jtex, how you did undervolt that baby? Beautiful!

Well, you just feed it 3V instead of 5. It will reduce your headroom along with the power draw, but it's fine with Shockman, because it has a rather heavy-handed compressor, so it will never drive the delay chip too hard, once you set the internal levels right. I used a DC-DC converter to go down from 9V to 3 without wasting much power.

JTEX wrote: ↑10 Jun 2022, 21:53

Reachahighernoon wrote: ↑18 May 2022, 10:43 Hey man, made a PCB based on the schematic and it does sound fantastic

But I got just one tiny issue

How can I get more volume out of this?

I should note that I used an LM741 for the first opamp instead of a TL061 and NE5532s instead of TL072 for the headphone amp stage

Sorry, belated reply. 741? I haven't seen one of those since I was about 18 or so (I'm 50 now). First op amp I've ever used. It's a very noisy chip by current standards. Also, not sure where you saw a TL061 or 072 in my schematic. Many op amps will work fine in the Shockman circuit, but I picked specific parts for specific reasons, mostly lownnoise and low power draw.

Maybe I am remembering wrong cos I am not familiar with many SMD opamps

Anyway, how can you increase the volume of this circuit?

Anyway, how can you increase the volume of this circuit?

Increase R41 and R61

I just discovered the TLC07x op amp family. Available in PDIP8, and significantly better than the old TL07x (much less noise, much higher output drive capability -- but pricier). If you want to build a Shockman with through hole parts and you don't care much about power consumption, it's worth trying.