Vari-Mu Compressor Project
- Thread starter analag
- Start date
Help Support GroupDIY Audio Forum:
I worked around Hartford, but East Hartford to be more specific. I wouldn't be too anxious to say I'm him though, could be someone else?
Identify yourself. I think I know who you are, I think we work at the same snakepit, I mean job. Maybe.
Analag
Identify yourself. I think I know who you are, I think we work at the same snakepit, I mean job. Maybe.
Analag
ToobieSnack
Well-known member
- Joined
- Mar 3, 2005
- Messages
- 493
snake pit ? ... i worked as an electrician and we used that term... are you an electrician too?
and hey learner ... love that avatar ..... i wish i could see it more clearly..
but ebody knows what a ribbon mic freak i am .. and i coiuldn'e help but notice this charachter is sitting on a magnet ... or magnetic himself hehe :grin: cool!
later
ts
and hey learner ... love that avatar ..... i wish i could see it more clearly..
but ebody knows what a ribbon mic freak i am .. and i coiuldn'e help but notice this charachter is sitting on a magnet ... or magnetic himself hehe :grin: cool!
later
ts
moosapotamus
Well-known member
[quote author="soundguy"]I built the acoustic 360 preamp he helped to backwards design and it works quite well.[/quote]
Cheers, Dave. Glad to hear that. :guinness:
:sam:
Thanks
~ Charlie
Cheers, Dave. Glad to hear that. :guinness:
:sam:Thanks
~ Charlie
ToobieSnack
Well-known member
- Joined
- Mar 3, 2005
- Messages
- 493
ok admittingly i am a newbie and maybe this is dumb but ....
if not .. there are still some errors here ...
is that AC power going to your input trafo???????????
and where is the power supply? ya know filament ... plate ... rectification?
should be a 5xx tube in here somewhere right?
also this design reminds me of my rca ba25 and the ba6a.
ALSO...which sim are you using .. widoze or mac?
later
ts
if not .. there are still some errors here ...
is that AC power going to your input trafo???????????
and where is the power supply? ya know filament ... plate ... rectification?
should be a 5xx tube in here somewhere right?
also this design reminds me of my rca ba25 and the ba6a.
ALSO...which sim are you using .. widoze or mac?
later
ts
moosapotamus
Well-known member
Ouch! I bit my tongue... :razz: :roll:
~ Charlie
~ Charlie
ToobieSnack
Well-known member
- Joined
- Mar 3, 2005
- Messages
- 493
ok daArry
i can see your point ... audio is ac ... but isn't that the symbol most commonly assocciated with the ac mains ...
and also the schematic is sans power supply for sim purpose this is ok i guess ... just looked funny to me with out the usual power supply section..
later'
ts
i can see your point ... audio is ac ... but isn't that the symbol most commonly assocciated with the ac mains ...
and also the schematic is sans power supply for sim purpose this is ok i guess ... just looked funny to me with out the usual power supply section..
later'
ts
I never said this was MY design. It's the Altec I just re-tubed her with more readily available tubes and changed a few resistor values around. Look up the Altec 436c for power supply setup and the other info you might need.
Larrchild
Well-known member
Consider these problems with this circuit.
"Transient peaks eventually charge the C10 filter cap and reduce the 6BC8 gain, but first the 6BC8 plate voltages rise a LOT. Both together, so the common-mode rejection of the long-tail 6CG7 "should" reject it. Except the 6CG7 pair can't take more than a few volts of common-mode without clipping (grid current), and the 6BC8 plates are bopping up 50V or 100V.
....the distortion happens when the "GR" meter M1 is -just- twitching."
this is from : http://www.omnipressor.com/Other/Altec.html
"Transient peaks eventually charge the C10 filter cap and reduce the 6BC8 gain, but first the 6BC8 plate voltages rise a LOT. Both together, so the common-mode rejection of the long-tail 6CG7 "should" reject it. Except the 6CG7 pair can't take more than a few volts of common-mode without clipping (grid current), and the 6BC8 plates are bopping up 50V or 100V.
....the distortion happens when the "GR" meter M1 is -just- twitching."
this is from : http://www.omnipressor.com/Other/Altec.html
Welcome, Larrchild.
> this is from :
Well, actually it is from my quill. I see it was at the Old Place; I'm glad it was preserved.
I stand by my points, but they are not fatal. In the original application, this grid-clipping meant that over-modulation could NOT happen, and the short burst of distortion as the caps charge is not too annoying and does avoid other problems (like cost). In rock-n-roll work, the initial transient clipping adds apparent loudness and punch. In the page you cite, he tried the "better" schemes and ended up nearly back to the original.
> this is from :
Well, actually it is from my quill. I see it was at the Old Place; I'm glad it was preserved.
I stand by my points, but they are not fatal. In the original application, this grid-clipping meant that over-modulation could NOT happen, and the short burst of distortion as the caps charge is not too annoying and does avoid other problems (like cost). In rock-n-roll work, the initial transient clipping adds apparent loudness and punch. In the page you cite, he tried the "better" schemes and ended up nearly back to the original.
Larrchild
Well-known member
Yes, agreed, and thanks for the welcome!
This fellow redid so much of the 436/8 that it was no longer a 436/8 and then promptly went back, when he took the Fun out of the sound!
That sonic signature of the transient getting momentarily soft-clipped probably adds some "wham" to the equation.
He also had not found the correct bias-point at first. That was the deal with the distortion with barely any gr occuring.
I had discovered that page a year ago and was more or less curious if the Aletecphiles here had considered it and if so, was it a bad thing?
This might also be the reason Fairchild chose a Big, Honkin power amplifier to drive the sidechain rectifier at a low impedance to get the r/c network charged up real fast (50us).
Sounds like we need a new design spec: "Transient Harmonic Distortion" lol
Analag, how do those push-pull transformers like having no center-tap ac ground path?
This fellow redid so much of the 436/8 that it was no longer a 436/8 and then promptly went back, when he took the Fun out of the sound!
That sonic signature of the transient getting momentarily soft-clipped probably adds some "wham" to the equation.
He also had not found the correct bias-point at first. That was the deal with the distortion with barely any gr occuring.
I had discovered that page a year ago and was more or less curious if the Aletecphiles here had considered it and if so, was it a bad thing?
This might also be the reason Fairchild chose a Big, Honkin power amplifier to drive the sidechain rectifier at a low impedance to get the r/c network charged up real fast (50us).
Sounds like we need a new design spec: "Transient Harmonic Distortion" lol
Analag, how do those push-pull transformers like having no center-tap ac ground path?
G
Guest
Guest
[quote author="analag"]
Slightly tweaked Altec 436c
Analag[/quote]
seems to me as if some of the harsh undertones of some of the responding posts to this thread could have been avoided.
1st: if any of you see a flaw in a design, kindly state your opinion through PM. the chances of someone building it from start to finish before a correction is made to the schematic is very slim.
analag was just sharing a design (SHARING...CONTRIBUTING), and all of a sudden he's got people jumping all over him in an ego fest to point out all of his potential problems with a design.
you backed him up in a corner...what did you think was going to happen?
pm the dude, and he'll correct it im sure.
Slightly tweaked Altec 436c
Analag[/quote]
seems to me as if some of the harsh undertones of some of the responding posts to this thread could have been avoided.
1st: if any of you see a flaw in a design, kindly state your opinion through PM. the chances of someone building it from start to finish before a correction is made to the schematic is very slim.
analag was just sharing a design (SHARING...CONTRIBUTING), and all of a sudden he's got people jumping all over him in an ego fest to point out all of his potential problems with a design.
you backed him up in a corner...what did you think was going to happen?
pm the dude, and he'll correct it im sure.
Larrchild
Well-known member
I hope everyone knows that everything I posted was directed at the general design ideas of people cloning 436/8's as a way to learn the nuances of all this. All the stuff i cited was from another clone project. and I also quoted PRR, cause his point made me think.
Except for my last line, which was to analag. I've seen them connected like that with a "Phantom Center" and was curious.
Except for my last line, which was to analag. I've seen them connected like that with a "Phantom Center" and was curious.
G
Guest
Guest
[quote author="Larrchild"]I hope everyone knows that everything I posted was directed at the general design ideas of people cloning 436/8's as a way to learn the nuances of all this. All the stuff i cited was from another clone project. and I also quoted PRR, cause his point made me think.
Except for my last line, which was to analag. I've seen them connected like that with a "Phantom Center" and was curious.[/quote]
yup, and i got a feeling as if your post was actually trying to help...
i just think my overall point was that we can all be a little more civil around here, instead of pushing around our knowledge to make ourselves feel better rather than sincerely trying to help someone.
:grin:
Except for my last line, which was to analag. I've seen them connected like that with a "Phantom Center" and was curious.[/quote]
yup, and i got a feeling as if your post was actually trying to help...
i just think my overall point was that we can all be a little more civil around here, instead of pushing around our knowledge to make ourselves feel better rather than sincerely trying to help someone.
:grin:
Winston OBoogie
Well-known member
...
Thank you LoFi, I've had my butt kicked around since I came on this forum, I quess my style is upsetting to the average Joe. I think you have those who build and those who talk about building. We build OK. Check out my first thread... I was invited to leave the forum, I think I made history with that one. See optical compressor. And thanks for the support.
Rowan
Rowan
tk@halmi
Well-known member
[quote author="analag"]I was invited to leave the forum, I think I made history with that one...
Rowan[/quote]
LOL. You were not the first one, but I don't think that was called for anyhow.
I offer this post sincerely as constructive criticism and I hope you take it as such, and not as an opportunity to lash out.
The schematics you publish are vague and present more questions than answers. An engineer must be precise and offer clarity either through the schematics or by attached explanation. The theory of operation and some details of construction will be most appreciated by your audience here. It will minimize misunderstanding. I am sure they have impressed upon you in engineering school: fit your presentation to the audience and you are going to communiate successfully. Not every person is an engineer on this forum. On the contrary, most patrons are just looking here for hobby projects, and have basic knowledge of electronics.
We would love to see your next project and have a civilized dialog about it.
Cheers,
Tamas
Rowan[/quote]
LOL. You were not the first one, but I don't think that was called for anyhow.
I offer this post sincerely as constructive criticism and I hope you take it as such, and not as an opportunity to lash out.
The schematics you publish are vague and present more questions than answers. An engineer must be precise and offer clarity either through the schematics or by attached explanation. The theory of operation and some details of construction will be most appreciated by your audience here. It will minimize misunderstanding. I am sure they have impressed upon you in engineering school: fit your presentation to the audience and you are going to communiate successfully. Not every person is an engineer on this forum. On the contrary, most patrons are just looking here for hobby projects, and have basic knowledge of electronics.
We would love to see your next project and have a civilized dialog about it.
Cheers,
Tamas
