The Optical Comp Again

analag

Well-known member
Joined
Apr 23, 2005
Messages
1,699
Location
Mars
Comp.jpg


I still get a few requests for this one, mostly via PM's so here we go guys. A friend was doing the PCB for it....
This is a great candidate for Edcor XSM10K:10K (input) and XSM10K:600 (output). These transformers are just too cheap you to construct it transformerless.
 

adamasd

Well-known member
Joined
Jun 17, 2004
Messages
472
Location
Duluth MN
Here it is again. Vactrol should be a dual type with the LEDs connected back to back, VTL5C4/2 is what I have in my notes. Edcor WSM10k/10k and XSM10k/600 should do well for the input and transformers, or equivalent types from your favorite brand. The G9 power supply is a perfect match for this just cut out the phantom supply.

A friend was doing the PCB for it....

You referring to me? Never did a PCB layout for a tube project before, seems like fun. Or do people want a Point to Point layout and do tubes how they were intended?[/i]

Edit; You beat me to the transformers. Any particular reason you chose the 2.5 watt XSM for the input?
 

sverige_cruz

Well-known member
Joined
Jun 4, 2004
Messages
63
Location
Sacramento, CA
For those that missed this one, this thing sounds great. Never did finish the PCB for it. Too busy. Point to point works fine though. If only I could get the poor man's now :cool: (hint-hint, please-please...)
 

analag

Well-known member
Joined
Apr 23, 2005
Messages
1,699
Location
Mars
[quote author="sverige_cruz"]For those that missed this one, this thing sounds great. Never did finish the PCB for it. Too busy. Point to point works fine though. If only I could get the poor man's now :cool: (hint-hint, please-please...)[/quote]

How can you ask for the Poor man if you couldn't finish the PCB, really.

The PSU can be made simpler than the G9...an MOSFet and a few other components. I have a standard design that is very rugged and very stable.
The quality and inductance range of the XSM lineup is better than the WSM from my experience and I have almost (30) Edcors in use here in my studio.
 

adamasd

Well-known member
Joined
Jun 17, 2004
Messages
472
Location
Duluth MN
The quality and inductance range of the XSM lineup is better than the WSM from my experience

Ahh, figured it was something like that. I do not have much experience with edcors transformers yet, mostly just their SE output transformers.

How can you ask for the Poor man if you couldn't finish the PCB, really.

and how could you ask for the poor mans 660 when you could ask for the insane mans 670?
 

analag

Well-known member
Joined
Apr 23, 2005
Messages
1,699
Location
Mars
The poor man is very fast with lots of stopping power, punchy lows like a great solidstate unit, but with that sweet mid and highs like the better tube units are known for.
But one at a time shall we?
 

adamasd

Well-known member
Joined
Jun 17, 2004
Messages
472
Location
Duluth MN
Hah, yeah I am focusing on this one compressor. I have alot more interest at this time in an optical compressor then a vari-mu. I have been making some headway with the PCB layout, its abit slow since I am just not used to doing tube stuff on PCB. It is alot more fun then solid state PCB work, DIPs suck.

Abit over 3 watts going through that 2.35K resistor feeding the control amp? Thats my guesstimate, still need to sort out what kind of current u6 can pull. That will wait for tomorrow, time to go be social.

adam
 

walter

Well-known member
Joined
Jun 21, 2006
Messages
412
Location
Seattle Wa. U.S.A.
So now we have a really lame layout for a forum that sucks. I am so happy I think I will wet myself. :twisted: Too many :sam: :sam: :sam: :guinness: I think I may build a point to point version, It's not really DIY if you just stuff a PCB. Plus I haven't made a PCB since Highschool, I don't even have any ACID! :green:
 

adamasd

Well-known member
Joined
Jun 17, 2004
Messages
472
Location
Duluth MN
Point to point or a turret board is the ideal way for me on this sort of project. The PCB is just to make it accessible to more people

wow. I sure could have used that when I built this thing.

What exactly is it? It is pretty what ever it is. [/i]
 
G

Guest

Guest
Analag;

it is not a compressor, it is a half-wave limiter. Most probably oscillating one.

You need to rectify controlling signal.
 

dale116dot7

Well-known member
Joined
Jun 5, 2004
Messages
866
Location
Calgary, Alberta, Canada
It is rectified - he mentioned that the vactrol needs to be the dual-LED type with the LED's connected back-to-back. The control voltage portion (rectification and attack-release) is not needed because the time constant of the CdS photocell in the vactrol provide the attack and release equivalent 'R' and 'C'. Compare carefully with an LA2. Nice work, I say!

Kiira, I like the looks of that! Is that predrilled turret board that you staked, or did you have to drill all of the holes?

-Dale
 

emrr

Well-known member
Joined
Apr 12, 2006
Messages
7,749
Location
NC, USA
[quote author="Wavebourn"]Analag;

it is not a compressor, it is a half-wave limiter. Most probably oscillating one.

You need to rectify controlling signal.[/quote]


There's an entire thread about this already; it's tested and proven.
 

kiira

Well-known member
Joined
Aug 2, 2004
Messages
536
Location
Baltimore - Blobsville USA
Thank you all for the compliments. It's an opto compressor I had an idea for and which everyone here helped me with. The compression part, the opto element isn't on the board yet. It is NYDave's one bottle with a 10k:10k input xformer, the opto element will be driven by a edcor transformer... the borken one there is just a place marker. The makeup gain is a 2x6BX7 line stage and I think that is a 10k:10k Jensen. I forget. I have to dig out the schematics and notes I made. I build everything on turret boards because it looks nice and it is the only way I can figure out how to put something together from a schematic. It takes me days sometimes.

The turret board is glass and I drilled it myself. I was building a box with a mic-pre, tube comp and passive inductor EQ all in one, so I am building everything on these turret boards to make it neat and compact and kind of modular. I have the passive EQ board done as well.
I was planning on using one of Paul's (S) PS boards for the power supply.
I got interupted by something, I think I started dating somebody, so I haven't gone forward on it again because I am too busy playing music now.

edit: if I had seen Rowan's design I simply would have built that instead. I could fit that on a turret board easily. My confidence in my ability to design and troubleshoot things is very low, even with all the help I get here, so I would rather just build something that I know works and sounds good. I still may... I can use the two pre's on the board in the picture for all kinds of stuff... like a one bottle mic pre and the 6BX7 stage could be makeup gain for the passive EQ. Or maybe make it into one monster high gain mic pre. Er no, I would put the passive EQ in between the two amps.

Kiira
 

emrr

Well-known member
Joined
Apr 12, 2006
Messages
7,749
Location
NC, USA
[quote author="kiira"] I haven't gone forward on it again because I am too busy playing music now.[/quote]


Reality seems perfectly aligned then!
 

PRR

Well-known member
Joined
Jan 30, 2010
Messages
11,144
Location
Maine USA
> You need to rectify controlling signal

The control signal is light. The control input is light on the photo-resistor. The signal IS "rectified"; or rather, light of "either polarity" drops the signal.

The "release capacitor" is chemical action in the LDR.

Yes, it is also possible to rectify and peak-hold the audio to the LED. But the LDR is slow, and two time-constants in the loop gets unstable. I've done it (and with two such loops); but it is cheap and musically useful to just hold the LDR against the system OverLoad LED.

> the vactrol needs to be the dual-LED type with the LED's connected back-to-back.

Not essential to the light-control action. A one-way LED will work, though half-wave. (In this case, the capacitor coupled amplifier will probably punk-out unless you swamp the LED with a resistor or with another LED; but in general, half-wave limiters can be useful for most audio except maybe male speech.)
 

dale116dot7

Well-known member
Joined
Jun 5, 2004
Messages
866
Location
Calgary, Alberta, Canada
Once I outfitted a live PA board with an opto in the gain control circuit, with the LED triggered by the overload lamp. Instant opto compression on every channel, no clipping no matter how hard someone (or something?) decided to sing.

-Dale
 
G

Guest

Guest
[quote author="emrr"][quote author="Wavebourn"]Analag;

it is not a compressor, it is a half-wave limiter. Most probably oscillating one.

You need to rectify controlling signal.[/quote]


There's an entire thread about this already; it's tested and proven.[/quote]

Thank Doug!

I've bought some "slow opto couplers" :thumb:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150128266168
 

Latest posts

Top