clintrubber

Re: Amp with motorized pots
« Reply #20 on: January 15, 2020, 07:35:00 AM »
So they drilled some hole in the back I understand?

As an alternative/easier:
there's also this type as I mentioned above, with rear-screwdriver-slot (attached pic).

This transfers the mechanical job to the shaping of the shaft of the rear-pot.


Another alternative, if possible, is to find alike pots (one with motor, but wrong value, - the other with the desired value)
and swap the resistive sections.


CJ

Re: Amp with motorized pots
« Reply #21 on: January 15, 2020, 02:36:24 PM »
skip the pot nightmare and do modules like this Seymour Duncan Convertible.

find five tones that you like by breadboarding  tone stacks and gain structures, then build relay activated daughter boards.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

sonolink

Re: Amp with motorized pots
« Reply #22 on: January 15, 2020, 02:57:41 PM »
That amp is very interesting actually, I didn't know it existed, but honestly CJ, did you ask yourself what the hell I'm after with this project?

The whole idea is being able to change the amp settings on the fly with a click (or a stomp) without leaving the analogue tube world. I would think for instance a great use for the gain pot and the eq if the amp has a TMB. If It is a 2 channel amp there's even more reasons for it to be useful.

Thanks for the idea anyway

Cheers
Sino


Why sleep when you can mix?
M.P.Stavrou

CJ

Re: Amp with motorized pots
« Reply #23 on: January 15, 2020, 03:46:38 PM »
i got ya,

here are a few more pics, jus for the heck of it,

this amp was not very popular and did not last long,
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

sonolink

Re: Amp with motorized pots
« Reply #24 on: January 15, 2020, 05:14:57 PM »
Well it certainly is an interesting approach especially for that time ;)
Thanks for the pics

Cheers
Sono
Why sleep when you can mix?
M.P.Stavrou

clintrubber

Re: Amp with motorized pots
« Reply #25 on: January 17, 2020, 06:13:43 AM »
here are a few more pics, jus for the heck of it,

this amp was not very popular and did not last long,

Modular a great idea nevertheless, but can well imagine it didn't really catch on.

FWIW, 'modular' keeps existing in one form or the other, like  the stuff from
http://www.synergyamps.com/

sonolink

Re: Amp with motorized pots
« Reply #26 on: January 26, 2020, 11:08:27 AM »
Hi guys,

I have decided to not go any further with this project for the moment because the best solution seems to be using miniature dual shaft stepper motors (Nema 8 ) and I can't really find cheap enough ones. The cheapest ones I found are around 10€ a piece...

The following thread is very enlightening and is around 10 years old. Hopefully in  a near future prices will drop down.
https://www.diystompboxes.com/smfforum/index.php?topic=87943.0

Cheers
Sono
Why sleep when you can mix?
M.P.Stavrou

buckethead

Re: Amp with motorized pots
« Reply #27 on: March 25, 2020, 12:17:36 PM »
Hey guys,

I just had to dig out this thread, because I got the first prototype of my version of a motorized pot running today.   :)

Short video of it in action:
https://youtu.be/7h1DNU5zmfs

The stepper is a Nema 17, very oversized for this application, but widely available and not super expensive imho. If anyone knows of a source for low profile steppers with dual shafts, please let me know.

I designed a small PCB with a controller + stepper driver, which also serves as the carrier for the potentiometer - in this case a dual-gang 1M log Alpha type.

There's still a lot of space for improvement and testing, but I'm very happy with the first results...I just love watching that chickenhead move by itself  ;D

Best regards,
Mathias

sonolink

Re: Amp with motorized pots
« Reply #28 on: March 25, 2020, 01:23:50 PM »
OMG Mathias!!!! That is really beautiful :8

I tried finding smaller double shaft NEMAs but wasn't lucky enough :(

Congrats mate!! ;)
Why sleep when you can mix?
M.P.Stavrou

Gus

Re: Amp with motorized pots
« Reply #29 on: March 25, 2020, 04:35:41 PM »
Do you get any noise into the audio when the stepper output driver electronics are running?


sonolink

Re: Amp with motorized pots
« Reply #30 on: March 25, 2020, 05:49:51 PM »
He shouldn't if both circuits are kept independent (audio and pot control)
Why sleep when you can mix?
M.P.Stavrou

buckethead

Re: Amp with motorized pots
« Reply #31 on: March 26, 2020, 06:34:41 AM »
Do you get any noise into the audio when the stepper output driver electronics are running?

He shouldn't if both circuits are kept independent (audio and pot control)

Hey guys!

I will soon try how it behaves in an audio circuit, especially in a high gain guitar amp. The driver circuit is seriously noisy, but it is only active when it turns the stepper -> it gets a turn command, it turns and then it goes to sleep. Worst case I'm implementing a momentary mute fet right before the output stage, so it mutes the amp while the steppers do their thing. We will see :)

Besides that I'm worried about mechanical noise, those steppers have a lot of power. Imagine five of those rattling on an aluminium chassis...what will the tubes on that same chassis think of that? :D Still a long thinking process...

Best regards,
Mathias 

sonolink

Re: Amp with motorized pots
« Reply #32 on: March 27, 2020, 01:26:06 PM »
If it's in a guitar amp the tubes will be isolated by the chassis anyway. If not, you can always isolate them ;)

https://drive.google.com/open?id=1CmSO5HGgInH8-5onPfpa2U2XnTemH1Vb

https://drive.google.com/open?id=1-CunxsZAwitIbhTYfBvp5UEcEN9QgvtR

Why sleep when you can mix?
M.P.Stavrou


 

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