Meaning what you already have is quite good.
You asked about 741b which would definitely merit replacement, but TL071 there, besides being quite good, is just a small part and is used very conservatively., as in:
1) noise is being taken care of by the bipolar front end.
2) Op Amp is used with very low gain (meaning a lot of NFB), which extends its bandwidth and lowers its distortion by a big factor.
3) anyway sound goes through a ton of other stages, so improving a little just this part won't make an audible difference in the full mixer performance.
And remember this is a very good, properly designed mixer.
You asked about 741b which would definitely merit replacement, but TL071 there, besides being quite good, is just a small part and is used very conservatively., as in:
1) noise is being taken care of by the bipolar front end.
2) Op Amp is used with very low gain (meaning a lot of NFB), which extends its bandwidth and lowers its distortion by a big factor.
3) anyway sound goes through a ton of other stages, so improving a little just this part won't make an audible difference in the full mixer performance.
And remember this is a very good, properly designed mixer.
From what I am able to understand, my mixer has that circuit but with 741 chips
It seems the following generation tlo71 's were used. I wish I could find schematics for the rest of the channel. Would a photograph of the circuit work to help analyze. This is for a studiomaster 1977 12 channel mixer.
Thank you all.
It seems the following generation tlo71 's were used. I wish I could find schematics for the rest of the channel. Would a photograph of the circuit work to help analyze. This is for a studiomaster 1977 12 channel mixer.
Thank you all.
Last edited:
Sorry here is the drawing
You chopped off the ESP Audio logo on the schematic ?
Low Noise Balanced Microphone Preamp
By Phil Allison
(Edited by Rod Elliott - ESP)
Updated 17 May 2008
But if that's a Rodd Elliott design why are you showing it if you have a Studiomaster/RSD mixer with a different circuit and parts?
It's like going to the Doctor and show him a friend's X ray plate.
Yea, I know, both of you have a heart, lungs, liver, etc
By the way, you shouldn't have obscured that you were posting a Rodd Elliott propietary design.
It's like going to the Doctor and show him a friend's X ray plate.
Yea, I know, both of you have a heart, lungs, liver, etc
By the way, you shouldn't have obscured that you were posting a Rodd Elliott propietary design.
But if that's a Rodd Elliott design why are you showing it if you have a Studiomaster/RSD mixer with a different circuit and parts?
It's like going to the Doctor and show him a friend's X ray plate.
Yea, I know, both of you have a heart, lungs, liver, etc
By the way, you shouldn't have obscured that you were posting a Rodd Elliott propietary design.
Yes, Rod Elliots designs are all copyright. If any of you want to link to a circuit of Rod's then please put a direct link to the project concerned.
(rodrigosalvata... I've deleted the E.S.P. diagram. If you want to repost then put a link as outlined above. Thanks )
To me its like going to the doctor with xrays of an alien with 1 heart, 2 brains and 5 lungs, and asking how it works.
I had stated above that I was already aware of my mistake, but perhaps was not clear enough.
Copyright or not, I regret not showing enough respect for someone elses work.
What made me to be curious about my mixer was thinking it had a common, well regarded and upgradable circuit, but I have not yet enough knowledge to know what is common and not.
I had stated above that I was already aware of my mistake, but perhaps was not clear enough.
Copyright or not, I regret not showing enough respect for someone elses work.
What made me to be curious about my mixer was thinking it had a common, well regarded and upgradable circuit, but I have not yet enough knowledge to know what is common and not.
http://www.audioschematics.dk/downloads/schematics/consoles/sm 16-4 channel.tif
I have found here the exact schematics for the mixers channel.
Is it possible to determine which op amps can be swithed for tlo71 or 5534?
Also which are the signal, coupling and de coupling caps?
Thanks
I have found here the exact schematics for the mixers channel.
Is it possible to determine which op amps can be swithed for tlo71 or 5534?
Also which are the signal, coupling and de coupling caps?
Thanks
After a 30-second visual scan I don't see anything that isn't compatible with a TL071. If the 10 pF capacitor in the uA748 "Presence" filter really DOES connect to pin 6 (the opamp output) instead of pin 8 ("compensation" on the uA748; not used on the TL071) then it should be removed.http://www.audioschematics.dk/downloads/schematics/consoles/sm 16-4 channel.tif
I have found here the exact schematics for the mixers channel.
Is it possible to determine which op amps can be swithed for tlo71 or 5534?
Also which are the signal, coupling and de coupling caps?
Thanks
The 220 uF capacitors in the "LED DRIVE" section of the circuit are power supply bypass capacitors (also called decoupling capacitors). The 33 uF capacitor in the LED DRIVE circuit is a smoothing capacitor for the clipping indicator. Every other capacitor in that diagram is in the direct signal path, though some of them don't have much effect on some frequency ranges. The signal coupling capacitors are the large electrolytics - 10 uF, 100 uF and 1000 uF.
Dale
But if that's a Rodd Elliott design why are you showing it if you have a Studiomaster/RSD mixer with a different circuit and parts?
It's like going to the Doctor and show him a friend's X ray plate.
Yea, I know, both of you have a heart, lungs, liver, etc
By the way, you shouldn't have obscured that you were posting a Rodd Elliott propietary design.
is this : Low Noise Balanced Microphone Preamp , aside from the opamps used, the same circuit as this attached Drawing sent to me by the guy who Designed the RSD/Studiomaster 12 into 2, from 1977, I am working on.
If so, would I be hurting or helping the attached design by replacing the 741´s with tlo71´s? Is it possible to describe what, in theory, would change? Just finished recapping and everything is stable.
thanks,
Rod
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