SUPERMAGOO
Well-known member
It would be great to show us some audio drums through this terrible monster child!
6bj6 you use for this audio amp?
why use EL34?
6bj6 you use for this audio amp?
why use EL34?
original 670 poor version DIY
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SUPERMAGOO
Well-known member
viewed on your amp control.
quickly put in my control-amp el34.
a first impression seems to be a little stronger and faster.
I will test again with more time.
It would seem that you had a very good idea.
quickly put in my control-amp el34.
a first impression seems to be a little stronger and faster.
I will test again with more time.
It would seem that you had a very good idea.
I cloned the 670 but not quite. I don't want to say I improved on the design because that's blasphemy to such a worshiped compressor. I built it as symmetrical as I could even down to the coil structure in the OPT's. GR amp is 8:1 step down, CV amp is 4:1 step down. In the CV output I used a large core to minimize the amount of turns needed to achieve the desired impedance, this made the application of feedback from the tertiary winding much more stable. I ended up winding them twice before I was satisfied. 6L6GC are used but triode connected and driven hard by 12AT7 into 5687 into 6L6GC. The EL34 is in the center of the chassis that is connected to a 6AU6 error amp on the underside of the thing. Steps were taken to minimize tube drift and increase the regulatory capacity of the circuit. All heater supply is AC and center terminated to GRN. No hum. There's more to it too...how does it sound...take a guess.
SUPERMAGOO
Well-known member
wow. 
you are the genius who created the Poorman!
maybe you could help me.
I calculated the controlamp winding transformer.
See if it is correct. the ratio used is: 10:4:9,5
Core: 18.9 cm2 ordinary silicon steel.
primary turns: 2000
secondary turns (12bh7 feedback): 88.
secondary turns 2 (control amp out): 490.
Minimum Frequency: 32hz.
another thing is that I have doubts about the working conditions of 2c51. in my last version I used 5 tubes.
I have achieved a good performance with my ears but I suppose that understanding the conditions of work can lead to better performance.
in my next audio amp that I am undecided .... Select Valve 6ba6*10, 6bj6*10 or again 2c51*5?
another question ... in your power supply are using 6au6 instead of 6084?
(remember to have patience I'm a disaster with the English).
greetings.
you are the genius who created the Poorman!
maybe you could help me.
I calculated the controlamp winding transformer.
See if it is correct. the ratio used is: 10:4:9,5
Core: 18.9 cm2 ordinary silicon steel.
primary turns: 2000
secondary turns (12bh7 feedback): 88.
secondary turns 2 (control amp out): 490.
Minimum Frequency: 32hz.
another thing is that I have doubts about the working conditions of 2c51. in my last version I used 5 tubes.
I have achieved a good performance with my ears but I suppose that understanding the conditions of work can lead to better performance.
in my next audio amp that I am undecided .... Select Valve 6ba6*10, 6bj6*10 or again 2c51*5?
another question ... in your power supply are using 6au6 instead of 6084?
(remember to have patience I'm a disaster with the English).
greetings.
SUPERMAGOO
Well-known member
tomelectro said:
thank you very much for the Scheme in high resolution!.
60p was tested in controlamp.
I can feel the high frequency roll-off.
I suppose that 47p is also roll-off too.
I will try 35p.
stability has improved a lot since I'm using the new
transformer winding with feedback (12bh7).
greetings.
SUPERMAGOO said:wow.
you are the genius who created the Poorman!
maybe you could help me.
I calculated the controlamp winding transformer.
See if it is correct. the ratio used is: 10:4:9,5
Core: 18.9 cm2 ordinary silicon steel.
primary turns: 2000
secondary turns (12bh7 feedback): 88.
secondary turns 2 (control amp out): 490.
Minimum Frequency: 32hz.
That's fine.
another thing is that I have doubts about the working conditions of 2c51. in my last version I used 5 tubes.
I have achieved a good performance with my ears but I suppose that understanding the conditions of work can lead to better performance.
in my next audio amp that I am undecided .... Select Valve 6ba6*10, 6bj6*10 or again 2c51*5?
another question ... in your power supply are using 6au6 instead of 6084?
(remember to have patience I'm a disaster with the English).
greetings.
I used 6BJ6 with screen and suppressor grid tied to plate. The old tube tektronix scopes uses the 6AU6 as error amp I did it and it works great.
Biasrocks
Well-known member
tomelectro said:
Any chance you could forward a copy to the group diy account?
groupdiy (at) gmail (dot) com
Mark
SUPERMAGOO
Well-known member
http://atvmagoo.googlepages.com/fairchild670-Blueprint-a.jpg
http://atvmagoo.googlepages.com/670_schematic_high-resolution.jpg
http://atvmagoo.googlepages.com/670_schematic_high-resolution.jpg
strangeandbouncy
Well-known member
Hi Supermagoo,
Thank you very much for this post. You have stirred me into action, and inspired me to have a go myself! Which edcor transformers did you use for in and out of signal amp? Also, how are you doing Gain reduction Metering? it is not on your schematic.
I am going to try to do this with a solidstate sidechain. Mainly to try save money, and a huge complicated powersupply!
you child sounds amazing on youtube by the way!
Kindest regards,
ANdyP
Thank you very much for this post. You have stirred me into action, and inspired me to have a go myself! Which edcor transformers did you use for in and out of signal amp? Also, how are you doing Gain reduction Metering? it is not on your schematic.
I am going to try to do this with a solidstate sidechain. Mainly to try save money, and a huge complicated powersupply!
you child sounds amazing on youtube by the way!
Kindest regards,
ANdyP
SUPERMAGOO
Well-known member
strangeandbouncy:
hi.
your message is really rewarding.
note that my compressor was a poor version.
I put things that I think might work.
I am not an engineer. I have not done serious calculations.
I am even hoping that some genius on this forum can help me
2c51 adjust better to their point of work.
This experiment has been important for several reasons:
1) is possible build a good compressor without esoteric parts.
2) so you can be strong and fast attack is needed hi controlamp power.
I recommend you try to do a valve controlamp.
I used an amplifier (solid state) in place of controlamp and was not so nice.
If you are interested I can send you the latest version of my schematic.
greetings
hi.
your message is really rewarding.
note that my compressor was a poor version.
I put things that I think might work.
I am not an engineer. I have not done serious calculations.
I am even hoping that some genius on this forum can help me
2c51 adjust better to their point of work.
This experiment has been important for several reasons:
1) is possible build a good compressor without esoteric parts.
2) so you can be strong and fast attack is needed hi controlamp power.
I recommend you try to do a valve controlamp.
I used an amplifier (solid state) in place of controlamp and was not so nice.
If you are interested I can send you the latest version of my schematic.
greetings
strangeandbouncy
Well-known member
Hi Analag,
I have used many tube vari-mu limiters over the years, including Fairchild, Gates STA-Level, RCA BA6, Altec, 175, Belcamon, EAR, Manley, and TAB. They are all good, indeed very good, but few are as flexible as the Fairchild. I find that only the EAR(not surprisingly) and 175 are as useful generally in the mix. The biggest problem I find with them is the lack of options with respect to time constants. I so often use something that adds some serious balls to a source and sounds awesome in isolation, only to have to remove it later, because it doesn't have a fast enough release, and messes with the overall balance. Sure, this sometimes doesn't matter, especially with multiple parallel feeds of, say, lead vox, where i find the STA great. I have been thinking of building an STA clone, or something as simple, but I would also like to LEARN something more at the same time. Even the STA is pricey in terms of iron. I figure that anything related to the Fairchild with it's usable Time Constants is preferable.
What I would like to do is build a limiter effectively as a modular project. Start by building the signal amp with modest iron, and use cheap tubes, 6ba6 ECC189 or 2c51. I think that you favour the 6ba6. If I go 2c51 route, I can always use JJ 6386 and Sowter later, when I've got it running properly. I am thinking of just using a mosfet power amp in bridge mode to start with!(and not use diode bridge) I can always get tubular later. This project can grow with my experience and budget. I am not trying to build an exact clone, and do not need to protect a transmitter. In my opinion there is almost no such thing as a crap compressor(with a few exceptions!). Anything that will provide some predictable dynamic control and/or Warmth/body/fatness-call it what you like is a bonus. If I don't like what I hear, I can build an authentic clone out of it. If I can learn more about the whys and wherefores on the way, so much the better. I figure I will learn much more mucking around with this than any of the other possible contenders. Worst case secenario, - I end up with a sweet sounding tube line-amp!
Any suggestions would be most welcome.
Kindest regards,
ANdyP
I have used many tube vari-mu limiters over the years, including Fairchild, Gates STA-Level, RCA BA6, Altec, 175, Belcamon, EAR, Manley, and TAB. They are all good, indeed very good, but few are as flexible as the Fairchild. I find that only the EAR(not surprisingly) and 175 are as useful generally in the mix. The biggest problem I find with them is the lack of options with respect to time constants. I so often use something that adds some serious balls to a source and sounds awesome in isolation, only to have to remove it later, because it doesn't have a fast enough release, and messes with the overall balance. Sure, this sometimes doesn't matter, especially with multiple parallel feeds of, say, lead vox, where i find the STA great. I have been thinking of building an STA clone, or something as simple, but I would also like to LEARN something more at the same time. Even the STA is pricey in terms of iron. I figure that anything related to the Fairchild with it's usable Time Constants is preferable.
What I would like to do is build a limiter effectively as a modular project. Start by building the signal amp with modest iron, and use cheap tubes, 6ba6 ECC189 or 2c51. I think that you favour the 6ba6. If I go 2c51 route, I can always use JJ 6386 and Sowter later, when I've got it running properly. I am thinking of just using a mosfet power amp in bridge mode to start with!(and not use diode bridge) I can always get tubular later. This project can grow with my experience and budget. I am not trying to build an exact clone, and do not need to protect a transmitter. In my opinion there is almost no such thing as a crap compressor(with a few exceptions!). Anything that will provide some predictable dynamic control and/or Warmth/body/fatness-call it what you like is a bonus. If I don't like what I hear, I can build an authentic clone out of it. If I can learn more about the whys and wherefores on the way, so much the better. I figure I will learn much more mucking around with this than any of the other possible contenders. Worst case secenario, - I end up with a sweet sounding tube line-amp!
Any suggestions would be most welcome.
Kindest regards,
ANdyP
strangeandbouncy
Well-known member
HI SuperMagoo,
I would absolutely love to see you schematic!
I just love your "have a go" attitude! Who cares if the result is not exactly the same as a 660. I know I would be very proud to use a limiter like yours.
KIndest regards,
ANdyP
I would absolutely love to see you schematic!
I just love your "have a go" attitude! Who cares if the result is not exactly the same as a 660. I know I would be very proud to use a limiter like yours.
KIndest regards,
ANdyP
strangeandbouncy
Well-known member
Hi Guys,
I was just wondering if someone could possibly explain how the DC threshold works. I know it affects the slope. I am out of my depth here, and cannot work out how it works, let alone how can it be achieved with a solidstate amplifier!
Kindest regards,
ANdyP
I was just wondering if someone could possibly explain how the DC threshold works. I know it affects the slope. I am out of my depth here, and cannot work out how it works, let alone how can it be achieved with a solidstate amplifier!
Kindest regards,
ANdyP
While many may be fascinated with implementing an SS sidechain, I am not. The quirkiness of the tube sidechain imposes itself directly into the compression characteristic of the device which I like. The beauty is to build a powerful amp with an output designed to put out the proper swing and impedance to slam those suckers into submission. If done right it can be blindingly fast...I have proof.
strangeandbouncy
Well-known member
SuperMagoo,
I would very much like to see your schematic, especially the metering section. Also, in one of your pictures it looks like you have FIVE dual triode tubes in your signal amp. Or did you use 4?
Kindest regards,
ANdyP
I would very much like to see your schematic, especially the metering section. Also, in one of your pictures it looks like you have FIVE dual triode tubes in your signal amp. Or did you use 4?
Kindest regards,
ANdyP
SUPERMAGOO
Well-known member
my apologies.
I am quite work.
is not my last version.
I am quite work.
is not my last version.
strangeandbouncy
Well-known member
Dear SuperMagoo,
Thank you very much! Why 5 x 2c51 by the way? When you possibly have some time, I am very interested to see how you made metering work, if possible.
Many thanks,
ANdyP
Thank you very much! Why 5 x 2c51 by the way? When you possibly have some time, I am very interested to see how you made metering work, if possible.
Many thanks,
ANdyP
SUPERMAGOO
Well-known member
my best work version to my ears...
SUPERMAGOO
Well-known member
strangeandbouncy said:
I was inspired by the child analag version.
uses 10 per 6bj6 channel.
also use the 40w-el34 amp control.
I have read of "PRR" that the more powerful is the controlamp / faster could be the vari-mu.
I have built several other mu-and nothing is as fast as this.
also produces an unusual change in the drums that seem to explode.
I'm fascinated with this compressor.
I put a link to the audio file.
attention to the snare. is taken with a 57 '
http://atvmagoo.googlepages.com/PRUEBAMC660.mp3
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