LA-4 Help Thread!

[justinheronmusic]

Does anyone have x2 PCb for this design that they aren't going to use? Otherwise is it still available?

 

[Patrick from Davis]

I know that DIY RE is trying to produce a LA-4 like 500 unit if you run out of options.  I can't comment on the other questions.

 

[Rybow]

Just looking back through the thread, I find it hard to believe that I started this project over 9 years ago, and to be honest, it's still not complete. I built a dual mono unit using the NSL 32 opto for one channel, and the VTL 5C4/2 for the other. The NSL 32 channel works great!

I have read a couple of posts about other folks having issues getting the VTL 5C4/2 to adjust correctly. I can get mine to about 60% of where it needs to be before I run out of adjustment (meter GR tracking & Ratio).  Considering these opto's have gotten a little rarer due to the European ban I've been considering swapping them out for NSL 6910's. Some googling round the net indicates that a company called Xvive is now producing them & they can be found at Small Bear Electronics.

Digikey has good stock on the NSL- 32 & NSL-6910 if anyone is interested.

Looks like the PCB is no longer available through Gustav (PCB Grinder), but maybe if enough of us band together he might do a small run.

Just a couple of small non critical items I need to address aside from the misbehaving opto before I can put the top on for good                                                             

 

[Gustav]

Just looking back through the thread, I find it hard to believe that I started this project over 9 years ago, and to be honest, it's still not complete. I built a dual mono unit using the NSL 32 opto for one channel, and the VTL 5C4/2 for the other. The NSL 32 channel works great!

I have read a couple of posts about other folks having issues getting the VTL 5C4/2 to adjust correctly. I can get mine to about 60% of where it needs to be before I run out of adjustment (meter GR tracking & Ratio).  Considering these opto's have gotten a little rarer due to the European ban I've been considering swapping them out for NSL 6910's. Some googling round the net indicates that a company called Xvive is now producing them & they can be found at Small Bear Electronics.

Digikey has good stock on the NSL- 32 & NSL-6910 if anyone is interested.

Looks like the PCB is no longer available through Gustav (PCB Grinder), but maybe if enough of us band together he might do a small run.

Just a couple of small non critical items I need to address aside from the misbehaving opto before I can put the top on for good                                                           

Highly unlikely that Ill be offering this, as long as theres a ban on the optos.

I do have a handfull of MS HOL boards, and a small drawer of Vactrols for it, but thats it.

Gustav

 

[jdiamantis]

I have found some info I saved on the opto grinder, but none on the HOL.

What differences are there between the 2 circuit wise?

Thanks.

jD

 

[Whoops]

I do have a handfull of MS HOL boards, and a small drawer of Vactrols for it, but thats it.

yes, I would also like to understand what are the diferencies between the LA4A project and the HOL?

thank you so much

 

[3nity]

Wow.
It took me 10 years to complete this build.. Its tracking and compressing very well.
Now i hope to complete the front plate soon.

 

[3nity]

Just to report.
I used this compressor on a voice track and wow what a great compressor.
i took out 5dbs and it took some harshness out of the track.
Anything on the box couldnt help at all.

 

[Whoops]

Just to report.
I used this compressor on a voice track and wow what a great compressor.
i took out 5dbs and it took some harshness out of the track.
Anything on the box couldnt help at all.

Nice, I'm really happy you were able to finish the project, I love the LA4A it's a great compressor.
Have fun with it.

I was going to buy the HOL pcb's from Gustav, 
but Gustav never explained whats the differences circuitwise between the HOL and the LA4A , neither by email or here in thread.
So then I bought one of these Lunny Tune's pcbs, and hopefully I can buy another one so I can do a Dual Mono unit.

what did you use for the Optos?
I remember at least 5/6 ago they were impossible to find

Thanks

 

[3nity]

I used vtl5c4/2
I was lucky and found 2.
I lost the other one.
Im not sure if vtl5c10 will work.
I have 4 if you need ill send them free.

Let me know

 

[Whoops]

Thank you so much 3nity,
and thank you so much for your offer.

I will not have anytime for this soon, so I will let you know in the future if I need any.

Thank you so much once again

 

[Piotr]

Hi to all of you,

I built this project quite a while ago, and used it happily ! I was testing it this morning to see if calibration had drifted and needed adjustment... it appears to be near perfect after a couple of years which attests of the quality of Torben Lysholm's and Rasmus Fris' pcb and project.

As I was reading about optos, I stumbled upon this page: http://www.xviveaudio.com/opto-couplers-p0065.html
You seem to be able to buy these at Banzai for example and if I'm not mistaken they are suited for this project. https://www.banzaimusic.com/Optocouplers/

Here's my take on it, the power pot shaft is still to be cut and fitted with a knob after all these years...

 

[gyraf]

Nice!

The xvive versions are unfortunately nowhere near how the Exelitas/PerkinElmer/EC&G/Vactec performed.

Yes, I am aware of the story that they claim (along with two other companies ) that they bought the Vactec production line when they discontinued. Alas, I have from relatively good authority that core elements from that production line was scrapped - and we're relatively certain that none of the technologies was transferred (to anyone)..

The only really similarity in the current available optocouplers are the physical housings and the naming. Yes, it's definitely still possible to use these, but you should be prepared to select the good optos from a very big handful of strangely-behaving-ones, if you want parameters like the original. Been there tried that

/Jakob E.

 

[Whoops]

Yes, I am aware of the story that they claim (along with two other companies ) that they bought the Vactec production line when they discontinued. Alas, I have from relatively good authority that core elements from that production line was scrapped - and we're relatively certain that none of the technologies was transferred (to anyone)..

That's really sad to know.
Would it be that hard to do it properly?
It's not even a complex design

 

[Rob Flinn]

Here's a pic of the dual La4 that I built a few years back.    It uses Looney Tunes pcb's but has UREI Iron & original switches.  It has 2 UREI cases  mounted behind the panel.  This is a good sounding box with the Looney pcb's.  I bought all the UREI parts in the black market 2 or 3 years ago as an unfinished project.  I had to design the front panel & a friend in Prague had it made for me.

 

[Whoops]

Looks pretty good,
congrats

 

[gyraf]

Would it be that hard to do it properly?
It's not even a complex design

The hard part is apparently the production tolerances, and AFAIK specifically the chemical-composition tolerances and prediction of such in the process that does all the difference - and was where the decades of experience enabled vactec&friends to do seriously good stuff.

/Jakob E.

 

[Whoops]

Thank you so much for explaining Jakob.

It's sad that they went to the work of producing an reissuing those Optos and then they didn't do it properly.
What a waste

 

[ArjaanAuinger]

Hi everybody, I lost the docs from the 2014 HOL and can't find it anywhere online. Does somebody still have them and could upload them?

Regards,
Ari

 

[JAY X]

Hi!

Where is R11 (2k2) (F.P.), on the 1.0 revision board? I can't find it!!

Jay x