Altec 436C Build Project (PCBs, schemes)

[Jitter]

Hi friends.
I wanna build a stereo varimu compressor Altec 436C. I found this post with docs and design PCB.
http://www.aresaudio.com/altec-436-c-reissue.html

I've any questions for a version in stereo dual.
If I wanna build in stereo... Can I operate the controls for two pcb's with a quad potentiometer in the Input and dual pots in attcack, release, treshold, etc? If possible?
What is the ratio or impedance for the OEP input transformer?

Thanks.

 

[shot]

This is REALLY interesting!!
Very nice and simple layout!
I'll look into it a bit more!


Regarding your question, my guess is that you can always build four deck switches with resistors. It's a bit more work but you'll be rewarded with very accurate stereo tracking on those switches. And it can be cheap if you want to avoid grayhill route and go for cheap chinese switches on ebay. There's a lot of them. Some can even be order assembled.

 

[ForthMonkey]

Thanks to share this!

I believe you can build stereo unit with quad pots but building dual mono is better to me.Stepped pots could be great for dual mono units to use with stereo.

I will try this one,i guess.And there are good projects,too!

By the way input transformer should be 15K bridging transformer,i guess.Which OEP model is this?

 

[ForthMonkey]

I've converted PCB dimensions to 1:1.

https://dl.dropboxusercontent.com/u/91809016/altecpcb.pdf

 

[iprovlek]

OEP A262A7E can be use with this compressor (600ohms to 600ohms)!

Serial connected give 2.4Kohms!

 

[ForthMonkey]

I'm starting this project today!

What about resistor's watt? There are two 5W resistors.But the others?I saw that someone used 2W for all other resistors.

But i believe manual says true...

http://www.dvq.com/hifi/images/436c.pdf

By the way there are two components (bottom left).Says "70".What are they?Capacitor or what?

 

[iprovlek]

Where says"70" I cant find?

 

[iprovlek]

I Find!

I think that is caps!

 

[ForthMonkey]

I Find!

I think that is caps!

What 70? pF? nF?

But i believe they are resistors.

They are between shield(ground) and center tap of transformer.I can't see in schematic.

I sent mail and learned what they are.0.47uF caps.

By the way they sell PCBs.Now waiting for price.If it's cheap,i would like to buy directly from them.

 

[iprovlek]

I will have this tubes for this compressor tommorow!

If someone need it let me know!!!

 

[ForthMonkey]

Got this email:

Hi...price is 25 euro for single PCB... 60 euro for 3 PCB. Shipping cost excluded.

If someone wants PCB,send email.

[email protected]

 

[kambo]

whats the point of having "rose" connection  ;D

 

[iprovlek]

This PCB have errors!

Input pot is wired wrong!!!

 

[iprovlek]

Aresaudio altec 436c!

 

[ding]

I'm trying to figure out what that .1uf cap is in the top middle and where is the timing cap is on the board. I have a hard time finding stuff as it is so it could totally be me.

 

[iprovlek]

Is it timing cap is after input trannie before input potentiometer (two 0.047Uf film caps)?On left corner of PCboard

Is it possible that two output film caps of 1uF,  cause distortion!

 

[iprovlek]

And you right Ding that 0.1uF caps even there on Altec schematics!

This is strange!

 

[ding]

And you right Ding that 0.1uF caps even there on Altec schematics!

This is strange!

Ok, yeah, bottom left is the timing cap. It would have helped to find it if the layout drawing for the volume pot was correct. As far as that .1uf cap I figure it was an error on their part that is never ment to be built. That little cap would be taking some serious punishment!!!! Notice that in the build pictures that cap is curiously missing.

 

[iprovlek]

So what to do with that 0.1uF cap!?Not to solder it?

I finish this compressor from Aresaudio and have lots of distortion on output!

I dont know what to do!

I solve input potentiometer error!I wired him like should be in schematics!

 

[ding]

Check  your voltages and start there. I would get in contact with the people you got the board from about your trouble and that cap. Maybe they have a support forum or something similar. What voltage rating is that cap anyways?