LA-4 Help Thread!

[Whoops]

Afaik, market has been vacuum-cleaned for every VTL5C4/2 out there - prices raised to insane heights just after it was clear that the production was discontinued (because of the EU ban on the optical cell).

If anyone knows of a good-priced stack of them out there, let me know: I know a guy who'd want them (for spare-parts)

I recently had to discontinue my G2 recording channel AND my G3 optical stereo comp - because of this issue...

Jakob E.

Hi Jakob, didn't know that.

Can you tell mode about the EU ban on the optical cell?
What was that ban? and why did it affect the VTL5C4/2 and not other optocouplers?

thank you

 

[gyraf]

ALL Ldr-based opto couplers are now banned in the EU - no execption whatsoever. Opto compression is over. Strange, but true... This because of the CdS in the photoresistor.

The specific VTL problem is about spares - company producing them discontinued the line. And no, there are no second source for that range.

Jakob E.

 

[Whoops]

ALL Ldr-based opto couplers are now banned in the EU - no execption whatsoever. Opto compression is over. Strange, but true... This because of the CdS in the photoresistor.

Thanks Jakob,
didn't know that.

Strange thing is that Silonex Optocouplers are widely available in Europe, I can find NSL32 everywhere, Farnell stocks them, so it seems the ban at the moment only affected the production of Vactec/Vactrol optocoupler:
http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryName=All%20Categories&selectedCategoryId=&gs=true&st=NSL32

Also Photoresistors, the component that has the banned CdS, is also available in all my go to European shops.
Maybe until the stock is over, but actually in Farnell there's only one mention of "Available until stock is exhausted" but the other units have no notes:
http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000006094&sort=P_INVENTORY|1&st=photoresistor&pageSize=25&showResults=true&aa=true&sf=502

 

[Whoops]

Afaik, market has been vacuum-cleaned for every VTL5C4/2 out there - prices raised to insane heights just after it was clear that the production was discontinued (because of the EU ban on the optical cell).

I recently had to discontinue my G2 recording channel AND my G3 optical stereo comp - because of this issue...

Jakob E.

Jakob, I see some people maker their own Optocouplers, with the knowledge you have and your measuring equipment couldn't you  make your own Optocouplers with similar characteristics to the VTL5C4/2?

I asking this because then you didnt have to discontinue  your G2 and G3 units.

How hard would it be to do something very similar to a VTL5C4/2 optocouplers?

 

[[silent:arts]]

You can't build that optocoupler without a photoresistor, can't you ...

 

[Whoops]

You can't build that optocoupler without a photoresistor, can't you ...

Ohh, I see what you mean Volker.

Legally Jakob coudln't sell the G2 and G3 because there would be  photoresistors inside those units.

Is that right?

 

[[silent:arts]]

There might be a way to legally sell a G2 or G3, like with tube gear, I'm not sure.

However, for the very same reason they don't build vactrols anymore they will stop (or already have stopped) producing the photoresistors.

 

[gyraf]

..the problem is that the VTLXYX/2 type photocouplers were based on LDR's that were dual-units-on-same-substrate, which made them track waaay better than what is possible with even careful selection. I'm not aware of any other manufacturer that managed to get this process right.

But you're right, making a LDR opto is not the main problem - the legal aspect of selling them is the painful thing..

Jakob E.

 

[Whoops]

..the problem is that the VTLXYX/2 type photocouplers were based on LDR's that were dual-units-on-same-substrate, which made them track waaay better than what is possible with even careful selection. I'm not aware of any other manufacturer that managed to get this process right.

But you're right, making a LDR opto is not the main problem - the legal aspect of selling them is the painful thing..

Jakob E.

I'm really sorry to know that Jakob.

I hope that a solution can be found.

 

[Whoops]

Anyone can please recommend from the transformers being sold by Hairball audio which ones could be successfully used in this project?

http://www.hairballaudio.com/catalog/parts-store/audio-transformers

 

[rmaier]

I used Cinemag CMOQ-2s that I purchased directly from  Cinemag. The unit sounds very nice.

 

[Whoops]

Anyone can please recommend from the transformers being sold by Hairball audio which ones could be successfully used in this project?

http://www.hairballaudio.com/catalog/parts-store/audio-transformers

Yes Cinemag works great,
But I was asking for which of the Ed Anderson reproductions sold by Hairball audio could be used in this circuit?

thanks

 

[Whoops]

Looking to buy one of this pcbs from Europe.
Please let me know if you have one to spare.

Thanks

 

[3nity]

Hi dudes.
I finish my la4 4 years ago...just testing lately.
I tried calibrating but i was impossible.
VU meter tracking was adjusted.
But tried inserting a 1K and meter wouldnt frop 5dbs...

Oh btw i used what i had at hand and used VTL5C10..not sure if swap to nsl-32 or the expensive  CTL5C4/2.

Any toughts.

 

[peaceq]

http://www.ebay.it/itm/NEW-VTL5C3-Optocoupler-Vactrol-VTL5C3-Series-PerkinElmer-/162486781540?hash=item25d4f78664:g:KG0AAOSwe7BWz-kA


source for v arious Vactrol Optocoupler ( including VTL5C4/2) for those who might be interested 

 

[delaystomper]

hi I'm reading about this project and already started etching some pcb , I'm excited about it does anyone have a mouser parts cart that i can use to order fast? thanks 

 

[memestudio]

Hello, wich are the timing capacitors for attack and release in this compressor?

 

[Harpo]

Hello, wich are the timing capacitors for attack and release in this compressor?

The type of LDR used ...

 

[peterc]

Heads up, NSL 32 optos are still available from RS Components.

RS stock no.2508662498

About $8-00

Peter

 

[memestudio]

The type of LDR used ...

And C6, C7?