VPI ADS modification

Hi Everyone,

New member here and very impressed with this forum.

I own a VPI Avenger Reference. I have succesfully managed so far to DIY modify the most of the parts of this turnatbles with outstanding results.

The problem which remains is the very unstable VPI ADS (Analogue Drive System). I have tried to source a ready contoller capable of driving the dual motors' rim drive with no success.

Has anyone ever tried to modify the VPI ADS system, or alternatively is there any alternative precise controller (to be noted that in my country the power is 220-230 VAC 50 Hz) which would offer a stable operation?

thank you in advance
 

TomWh

Member
2009-04-29 2:03 pm
There is a thread that started a few years back which has all the information to build a single, dual and 3 phase motor controller. The watts will be up to you. Hans started it then Ralph join in and of course Bill/Phoenix jumped in with a Sg4 he designed.

The thread started with Hans making a 2 phase controller for the hurst motor and then took on a life of its own. Bill in one of his own threads has a complete controller instructions. You could maybe use 2 of them and independently control each motor with 2 phase and lose the splitting caps. Search Sg4 and you should come up with quite a bit of information.

Enjoy the ride
Tom
 
If you're handy with electronics, you could build this digital sinewave generator:

DIY 4 Phase Sinewave Generator for Turntable Motor Drive

to replace the analog oscillators in the ADS. The sinewave enters the ADS amp section at the junction of R2 & R5 in the attached schematic. You should also remove relay K1 or cut the trace from K1 pin 2 to junction of R5 & C4.

You could replace one of the ADS controls with a rotary encoder to operate the SG4.

Edit: I see Tom posted while I was typing. Also, the ADS amplifier is not optimum IMO and users have reported noisy output transformers with the ADS; maybe the best course of action would be to replace the entire ADS main PCB with the SG4 and a TDA7292 class D amp and Amgis toroidal transformer, keeping only the case of the ADS as that can be the most expensive part of building your own PSU.
 

Attachments

  • VPI ADS Schematic.pdf
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I've seen ads for this PSU recently: Longdog Audio PSU.

It is quartz controlled so it should be more stable than the ADS, and it has the power to drive Lencos and Garrard tables so it should be able to drive a dual motor flywheel from VPI. I have no idea of the quality, but it does look interesting. £895.

Also, if you are looking for assistance, it might help if you post your location.
 
I've seen ads for this PSU recently: Longdog Audio PSU.

It is quartz controlled so it should be more stable than the ADS, and it has the power to drive Lencos and Garrard tables so it should be able to drive a dual motor flywheel from VPI. I have no idea of the quality, but it does look interesting. £895.

Also, if you are looking for assistance, it might help if you post your location.

Thank you Pyramid for reverting back. Cost is no object.
My location is in Greece
 

hirscwi

Member
Paid Member
2014-03-06 2:18 am
Indianapolis, IN, USA
Unfortunatelly I am not good with electronics, only with engineering.
But If somebody could built it for me I would be very happy to cover all of the expenses

If you don't go with a commercial product, I can build you the SG4 that Bill (Pyramid) mentioned. I've built 6 of these and they are great. Unfortunately I don't have any of the PCBs and microprocessors so you would need to see if those can be obtained. We might need to take this discussion to a PM so not to tie up a thread.
 
Rim

If you do not have a rpm gauge yet, Sota is selling Bill's road runner gauge. I would not be without one. Goes out to 33.333. This is a great piece of engineering. It can help with belt tension/idler adjustment etc...

Enjoy the ride
Tom

Dear Tom,

The issue is not the tension anymore or the precise adjustment, these are solved though many modifications. The issue is that I have to continuously adjust the speed by hand through the ADS sloppy dial knobs, as the ADS becomes very unstable with the time.

Therefore I am looking for a product, similar to Phoenix Engineering ingenious set.
 
If you don't go with a commercial product, I can build you the SG4 that Bill (Pyramid) mentioned. I've built 6 of these and they are great. Unfortunately I don't have any of the PCBs and microprocessors so you would need to see if those can be obtained. We might need to take this discussion to a PM so not to tie up a thread.

Thank you for your offer, which I would happily consider, however as I wrote earlier, my electronics skills are zero and I do th think that I could source the needed PCBs and microprocessors.

I don’t mind for the cost, if someone could built for me such a controller
 

hirscwi

Member
Paid Member
2014-03-06 2:18 am
Indianapolis, IN, USA
Thank you for your offer, which I would happily consider, however as I wrote earlier, my electronics skills are zero and I do th think that I could source the needed PCBs and microprocessors.

I don’t mind for the cost, if someone could built for me such a controller

I'm sorry that I wasn't clear. I am willing to obtain the parts. I would just need to verify if the microprocessor and PCB are still available. If you are interested, I think we should take this to a PM and not clog the thread.