Hi everyone,
I have a Sony TA-N77ES power amplifier which I'd like to upgrade and I'm looking for any experience and advises on the subject.
The amp is working, after fixing cold solder joints at the input board. I'm going to change all electrolytes, replace pots with sealed Bournes multiturn ones and change speaker terminals to modern 5-way heavy-duty binding posts. However, I'm wondering what else could be improved in this amp.
I'm going to increase the filtering capacity of the preamp power supply by bumping up C315, C316 and C381, C319 pairs from 9400 mkF to 11200 mkF using 100V electrolytes instead of 80V.
The power transistors have its own power supply with two 22000mkF/80V electrolytes and I'd like to replace them with 22K mkF/100V United Chemi-Con caps model E36D101LPN223TDB7M. All other electrolytes in the preamp section are Nichicon MUSE except one, C320/C370 of 22mkF/63V in the differential amp that is ELNA Cerafine. Some folks who modded a Sony TA-N80 ES amp which is almost identical to mine increased its capacity to 100 mkF. I couldn't find postings explaining reason for this; what do you guys think?
The amp has several fusible resistors in the signal path which I'd like to leave alone and a carbon 1KOhm R301/R351 resistor at the signal entry point that will be changed to 1% Vishay metal film. Nonpolar capacitors are mylar, film and mica. One of the mica caps, C304/C354 of 7pF/100V, is in the signal path. I don't know is it silver mica or not; who could suggest a good capacitor for this position? Or perhaps some other nonpolar capacitors deserve an upgrade?
I attached the schematics downloaded from HiFIEngine; red arrows on it shows the signal path.
All suggestions will be welcomed.
Thank you.
I have a Sony TA-N77ES power amplifier which I'd like to upgrade and I'm looking for any experience and advises on the subject.
The amp is working, after fixing cold solder joints at the input board. I'm going to change all electrolytes, replace pots with sealed Bournes multiturn ones and change speaker terminals to modern 5-way heavy-duty binding posts. However, I'm wondering what else could be improved in this amp.
I'm going to increase the filtering capacity of the preamp power supply by bumping up C315, C316 and C381, C319 pairs from 9400 mkF to 11200 mkF using 100V electrolytes instead of 80V.
The power transistors have its own power supply with two 22000mkF/80V electrolytes and I'd like to replace them with 22K mkF/100V United Chemi-Con caps model E36D101LPN223TDB7M. All other electrolytes in the preamp section are Nichicon MUSE except one, C320/C370 of 22mkF/63V in the differential amp that is ELNA Cerafine. Some folks who modded a Sony TA-N80 ES amp which is almost identical to mine increased its capacity to 100 mkF. I couldn't find postings explaining reason for this; what do you guys think?
The amp has several fusible resistors in the signal path which I'd like to leave alone and a carbon 1KOhm R301/R351 resistor at the signal entry point that will be changed to 1% Vishay metal film. Nonpolar capacitors are mylar, film and mica. One of the mica caps, C304/C354 of 7pF/100V, is in the signal path. I don't know is it silver mica or not; who could suggest a good capacitor for this position? Or perhaps some other nonpolar capacitors deserve an upgrade?
I attached the schematics downloaded from HiFIEngine; red arrows on it shows the signal path.
All suggestions will be welcomed.
Thank you.
Attachments
Parts Selection for Sony TA-N77ES Amplifier Resoration
My amplifier is also the Sony TA-N77ES. It has a shorted output transistor which needs to be identified and replaced. I also want to do a restoration of the amplifier, including a full recap. Maybe we can share research on the best parts to use. Here is the information I have collected so far along with some of my questions.
The bulletins, service manual, and owner’s manual for the amp are all here:
Sony TA-N77ES Manual - Stereo Power Amplifier - HiFi Engine
An amplifier project very much like what I want to do is shown in detail here on the following solid state forum. It was performed on the Sony TA-N80ES, which just lacks the power meters of the TA-N77ES.
Sony TA-N80ES recap and mod adventure - AudioKarma.org Home Audio Stereo Discussion Forums
I want to replace the bias and offset pots with multiturns as shown on the solid state forum. I am not sure of the best ones to use.
I was also thinking of replacing the input jacks with something like the WBTs, similar to what he did on the solid state forum. I wouldn’t necessarily remove the existing input board the way he did. I might just put some new jacks in an inch or two over, like the Mogami 7557G.
I would be interested in bypassing some of the Sony connectors/wires/boards and so on going to the output posts, along the lines of what the guy did on the solid state forum, if it could be done cleanly. I sort of don’t like the way the guy did his, soldering heavy gauge wire where it wasn’t meant to go and apparently damaging the traces.
I am wondering about the desirability of:
1. adding bypass caps as shown on the solid state forum.
2. replacing the rectifier diodes with something better.
3. replacing the transistors.
The Sanken C3856 and A1492 are now the 2SC3856 and 2SA1492.
2SC3856 ?Sanken Electric
2SA1492 ?Sanken Electric
4. replacing any resistors that might need it. If I will be using bigger/lower ESR caps and so on, I assume I will generate a larger inrush current. Do any resistors need to be of a larger power rating?... maybe replaced with some Dales or whatever… Also, are there any circuits, like the constant current sources or resistors in the signal path that would benefit from some 1% metal films in place of the originals? I am not sure at this point…
Maybe the AC power relay should be replaced with something of the same form factor but higher quality and with greater capacity. I was also considering putting a good AC cord on the amp. Some guys swear that helps. I see that the original designer used a two-prong cord. I assume it should stay that way. I am agnostic on the AC cord issue.
On my power supply board, only four of six capacitor spots are used, I would consider using them all, some versions of this amp use all six. A replacement close to the original that would fit in the amp would be the Nichicon LKG1K332MESCBK, but a better cap is the Cornel Dubilier 380LX472M100A042. Here is the cut sheet for that family of caps:
http://www.cde.com/catalogs/380-382.pdf
There are a couple of computer grade caps the amplifier uses that are potted as shown here. They are 22000µF 80V caps that appear to match the Nichicon LNT1K223MSE perfectly as shown in this link.
LNT1K223MSE Nichicon | Mouser
I would like to replace these. I am not sure how to address the potting issue. The new caps could just be installed free-standing like in most amplifiers as far as that goes, though it would be nice to preserve the aesthetics of the original layout. The Cornell Dubilier 101C223U100CC2B would appear to be a better choice than the Nichicon. They are the same form factor with better performance. Is there any reason (other than the more than doubled cost), not to use the Cornell Dubilier caps? They have lower ESR and will have a bigger inrush….
Here is the cut sheet for that family of caps:
http://www.cde.com/catalogs/101C.pdf
In replacing the other caps, service bulletins 215 and 57 need to be performed (four caps need to be new/larger size).
I would like to use Elna Silmic II caps wherever they fit. For the really small caps, I guess something like the Wimas will work. My intention is that none of the original caps survive the restoration.
I want to replace the incandescent lamps in the meters.
When you identify good parts to use in the amp, please give part numbers/brand/source… whatever you have…
My amplifier is also the Sony TA-N77ES. It has a shorted output transistor which needs to be identified and replaced. I also want to do a restoration of the amplifier, including a full recap. Maybe we can share research on the best parts to use. Here is the information I have collected so far along with some of my questions.
The bulletins, service manual, and owner’s manual for the amp are all here:
Sony TA-N77ES Manual - Stereo Power Amplifier - HiFi Engine
An amplifier project very much like what I want to do is shown in detail here on the following solid state forum. It was performed on the Sony TA-N80ES, which just lacks the power meters of the TA-N77ES.
Sony TA-N80ES recap and mod adventure - AudioKarma.org Home Audio Stereo Discussion Forums
I want to replace the bias and offset pots with multiturns as shown on the solid state forum. I am not sure of the best ones to use.
I was also thinking of replacing the input jacks with something like the WBTs, similar to what he did on the solid state forum. I wouldn’t necessarily remove the existing input board the way he did. I might just put some new jacks in an inch or two over, like the Mogami 7557G.
I would be interested in bypassing some of the Sony connectors/wires/boards and so on going to the output posts, along the lines of what the guy did on the solid state forum, if it could be done cleanly. I sort of don’t like the way the guy did his, soldering heavy gauge wire where it wasn’t meant to go and apparently damaging the traces.
I am wondering about the desirability of:
1. adding bypass caps as shown on the solid state forum.
2. replacing the rectifier diodes with something better.
3. replacing the transistors.
The Sanken C3856 and A1492 are now the 2SC3856 and 2SA1492.
2SC3856 ?Sanken Electric
2SA1492 ?Sanken Electric
4. replacing any resistors that might need it. If I will be using bigger/lower ESR caps and so on, I assume I will generate a larger inrush current. Do any resistors need to be of a larger power rating?... maybe replaced with some Dales or whatever… Also, are there any circuits, like the constant current sources or resistors in the signal path that would benefit from some 1% metal films in place of the originals? I am not sure at this point…
Maybe the AC power relay should be replaced with something of the same form factor but higher quality and with greater capacity. I was also considering putting a good AC cord on the amp. Some guys swear that helps. I see that the original designer used a two-prong cord. I assume it should stay that way. I am agnostic on the AC cord issue.
On my power supply board, only four of six capacitor spots are used, I would consider using them all, some versions of this amp use all six. A replacement close to the original that would fit in the amp would be the Nichicon LKG1K332MESCBK, but a better cap is the Cornel Dubilier 380LX472M100A042. Here is the cut sheet for that family of caps:
http://www.cde.com/catalogs/380-382.pdf
There are a couple of computer grade caps the amplifier uses that are potted as shown here. They are 22000µF 80V caps that appear to match the Nichicon LNT1K223MSE perfectly as shown in this link.
LNT1K223MSE Nichicon | Mouser
An externally hosted image should be here but it was not working when we last tested it.
I would like to replace these. I am not sure how to address the potting issue. The new caps could just be installed free-standing like in most amplifiers as far as that goes, though it would be nice to preserve the aesthetics of the original layout. The Cornell Dubilier 101C223U100CC2B would appear to be a better choice than the Nichicon. They are the same form factor with better performance. Is there any reason (other than the more than doubled cost), not to use the Cornell Dubilier caps? They have lower ESR and will have a bigger inrush….
Here is the cut sheet for that family of caps:
http://www.cde.com/catalogs/101C.pdf
In replacing the other caps, service bulletins 215 and 57 need to be performed (four caps need to be new/larger size).
I would like to use Elna Silmic II caps wherever they fit. For the really small caps, I guess something like the Wimas will work. My intention is that none of the original caps survive the restoration.
I want to replace the incandescent lamps in the meters.
When you identify good parts to use in the amp, please give part numbers/brand/source… whatever you have…
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