lolo-m
Well-known member
+1 ;D !jackies said:
"Another Poor Man's" Fairchild 660/670
- Thread starter rotheu
- Start date
Help Support GroupDIY Audio Forum:
lolo-m
Well-known member
Even if I'm not as clever as EAR, it is certainly close to PRR's varimu sidechain with a powerfull output as my SCAB. A combination of the 2 will work nicely IMO.jackies said:
jackies said:
I don't know, I have mixed feelings about sharing that, but it is there: http://www.mrschematic.com it is the 660.
You have to pay for it though. I can't imagine that Mr Pavaricini likes the idea of his circuit being public, it is still in production, but since it is there anyway and the comp is for my personal use only and I breadboarded it the hard way
....But you can send me a PM with your email and there it goes.
lolo-m said:
No it is not close to the prr circuit, it has a dc threshold implemented, that copies the fairchild way in solid state, but the output is like your SCAB, the TIP41 and 42 are driving AC into a transformer and then it gets rectified.
lolo-m
Well-known member
Quite complicated output !hop.sing said:
PRR's has got a DC threshold implemented but not variable.
lolo-m
Well-known member
Wow, those guys are crasy ! But it is certainly more Fairchildish !
Matthew Jacobs
Well-known member
I'm a shelf confessed Compression Mad, Fairchild Fanatic..... ;D
Sorry, people, I f***ed up! I feel very bad now! :-[
My apologies for this. I want to thank Hop.sing for noticing my mistake. It's crazy how obvious the mistake is when I look at it now, after he mentioned this. It's so in your face!
Matthew, I'm very sorry for causing you this problem, since you started building the switch! :-[
I just want to mention that I never claimed that I build the actual switch, you can look through the posts. I built the prototype signal and side chain amps and I tried all timing settings by soldering the resistors and caps and bypassing the original 660 timing network and they all worked great. I was planning to make a double sided PCB for this switch and use two PCB mount 2 pole 6 terminal Alpha switches. Normally, a switch is not something you make a prototype off, but I guess in this case I should off done that. I came up with this switch after I built the prototype compressor.
Also I never stated that this configuration sounds better than series resistance. This is the quote from my post:
Regarding efficiency, yes I agree that series resistance is more economically efficient than this configuration, but not electronically. After building 10W or 5W power amp, I don't think it's efficient to waste all that power as heat in the resistor.
There is one obvious solution for this. It is to use 6 deck 6 terminal switch for release. That will isolate the resistor butches for each cap. But unfortunately it's not a poor man's solution. That switch will cost a lot. At this moment I don't see any other way to do it, but I will think about it more and hopefully come up with something. This time I will definitely build it before I post anything!
I want to apologize again for all confusion and trouble I caused! :-[
My apologies for this. I want to thank Hop.sing for noticing my mistake. It's crazy how obvious the mistake is when I look at it now, after he mentioned this. It's so in your face!
Matthew, I'm very sorry for causing you this problem, since you started building the switch! :-[
I just want to mention that I never claimed that I build the actual switch, you can look through the posts. I built the prototype signal and side chain amps and I tried all timing settings by soldering the resistors and caps and bypassing the original 660 timing network and they all worked great. I was planning to make a double sided PCB for this switch and use two PCB mount 2 pole 6 terminal Alpha switches. Normally, a switch is not something you make a prototype off, but I guess in this case I should off done that. I came up with this switch after I built the prototype compressor.
Also I never stated that this configuration sounds better than series resistance. This is the quote from my post:
Regarding efficiency, yes I agree that series resistance is more economically efficient than this configuration, but not electronically. After building 10W or 5W power amp, I don't think it's efficient to waste all that power as heat in the resistor.
There is one obvious solution for this. It is to use 6 deck 6 terminal switch for release. That will isolate the resistor butches for each cap. But unfortunately it's not a poor man's solution. That switch will cost a lot. At this moment I don't see any other way to do it, but I will think about it more and hopefully come up with something. This time I will definitely build it before I post anything!
I want to apologize again for all confusion and trouble I caused! :-[
lolo-m
Well-known member
No problem ! Thanks for sharing your design ! Many thanksrotheu said:
!lolo-m said:No problem ! Thanks for sharing your design ! Many thanksrotheu said:
Hi Rotheu
Really no problem! A 1000 eyes must have stared at that for months and nobody noticed ;D
You share a lot, that is great!
If I sounded a little harsh, I want to apologize and sorry for misinterpreting your statement.
Series resistance might be wasted energy, but as long as it sounds the same like no series resistance but more capacitance I would choose a pot. In my tests I thought I heard a difference, but thinking about it, it is really difficult to discern, you would need kind of a blind test configuration, which I had not. And my expectations wanted to have the complicated version to sound better, all the work should be worth the trouble
Rotheu, you did a great job, and it is very educational to watch this thing develop, thanx for doing this, i'm looking forward to build mine. Now, i'm probably overseeing something, but isn't this new switch 7deck-6position and actualy using only two deck at the time ? The way it is drawn now,
the signal is going from the top deck to the far right deck through the 51K resistor to the GND?
Apologize if I'm just being thick ;D
the signal is going from the top deck to the far right deck through the 51K resistor to the GND?
Apologize if I'm just being thick ;D
Matthew Jacobs
Well-known member
rotheu said:
Hey man, no problem. I really had fun building that switch. I really don't see it a waste of time at all. I'm glad it helped in the development of this thread and the great schematic you have so kindly shared. I see it as such a small part compared to all the work you have put into this project. Thanks so much for sharing.
rotheu said:
Sorry if I insinuated that you had. I have been following this thread from the beginning and remembered that you commented on how quick this new network was and how you where amazed by it so I assumed it worked. I'm still a newbie and didn't realize that you could have prototyped it without building the switch. My apologies...
J
syn said:
The top two 6 position switches are ganged together for attack ( 2 pole 6 terminal switch ), the bottom six 6 position switches are ganged together for release ( 6 pole 6 terminal switch ). The attack switch will select the capasitor and it's corresponding set of release resistors, the release switch will connect the selected resistor from the set to the ground.
KrIVIUM2323
Well-known member
Hi every one and thank you sharing so much usefull infos!
I've got a question about the resistors (330/330/1,2k) at the junction output of signal amp transformer/ input of control amp transformer: is it a pad or a network for correctly loading the transformers...or maybe something else?
I've got a question about the resistors (330/330/1,2k) at the junction output of signal amp transformer/ input of control amp transformer: is it a pad or a network for correctly loading the transformers...or maybe something else?
Kingston
Well-known member
It's for futher isolating the sidechain from the audio output, just a pad basically.
KrIVIUM2323
Well-known member
Ok Thank You Kingston.
Matthew Jacobs
Well-known member
Hi Everyone,
I found a switch that might work for the release.
http://www.banzaimusic.com/Rotary-Switch-3-level-3x2x6.html
My understanding is that it has 3 levels. Each level has 2 poles with 6 positions.
This makes a total of 6 poles and 6 positions... Just what we need... Not expensive too...
J
I found a switch that might work for the release.
http://www.banzaimusic.com/Rotary-Switch-3-level-3x2x6.html
My understanding is that it has 3 levels. Each level has 2 poles with 6 positions.
This makes a total of 6 poles and 6 positions... Just what we need... Not expensive too...
J
