Threshold SL10 Phono Preamp Restoration
PRETEXT : This unit was obtained from a dear friend of mine, he doesn't belong to the forum, a good few months ago and restored by myself with the great help of [member=34]Shonver[/member] (Thank you Shaun). Without his continued patience, identifying replacement parts, advice and all the rounds of troubleshooting, I would not have been able to this. I did all the manual labour, enough said.
This unit did it's rounds on the forum and I managed to trace some of the earlier members that had this unit, and verified it was the same unit by the pots and marks of the power supply transformer, as can be seen in the post/pics below. This unit has traveled and I am very glad that I am the owner of it.
Here's the thread which gave me a clue to where this unit has travelled :
https://www.avforums.co.za/index.php?topic=19763.msg250857#msg250857
Nelson Pass, diyaudio.com and their resource base has also been invaluable in getting me started and through this too.
END RESULT : I sold my long held PS Audio GCPH Phonostage to make way permanently for the Threshold SL10 Phono Preamp, using its MC output stage. ( Clearaudio Wood/Essence cartridge/Modwright power amp/Vivid B1 speakers).
All the large capacitors were changed to Panasonics,Nichicon. So too were all the transistors to the relevant up to date equivalents ( more than 50 of them), the servo op amp, the volume pot to an Alps 10 Ohm rotary carbon film one, a couple of resistors( Vishays),both 7815 and 7915 regulators. All the RCA connectors and it's fittings replaced, it was a challenge as the old ones were large, could not be found and work had to be done with their modern replacements. It worked out fine in the end.
Shaun's suggestions of replacing the 20 Ohm volume pot with a 10 ohm one was indispensable as the gain was to high ( this is/was a universal problem), and I could fit sockets and play around with changing resistor values to suit my needs ( can be seen in the pics). This works and still in progress...
We had some motor-boating issues which tested our patience, over-ally it was worth all the effort, little monies and time spent, and I've been rewarded with a unit that gives and brings me great joy.
Some pics of the process till finish follows.
Finished unit, first :
There's still some work to be done, I have some ideas, but they will follow.....
Some other pics in the next post.
PRETEXT : This unit was obtained from a dear friend of mine, he doesn't belong to the forum, a good few months ago and restored by myself with the great help of [member=34]Shonver[/member] (Thank you Shaun). Without his continued patience, identifying replacement parts, advice and all the rounds of troubleshooting, I would not have been able to this. I did all the manual labour, enough said.
This unit did it's rounds on the forum and I managed to trace some of the earlier members that had this unit, and verified it was the same unit by the pots and marks of the power supply transformer, as can be seen in the post/pics below. This unit has traveled and I am very glad that I am the owner of it.
Here's the thread which gave me a clue to where this unit has travelled :
https://www.avforums.co.za/index.php?topic=19763.msg250857#msg250857
Nelson Pass, diyaudio.com and their resource base has also been invaluable in getting me started and through this too.
END RESULT : I sold my long held PS Audio GCPH Phonostage to make way permanently for the Threshold SL10 Phono Preamp, using its MC output stage. ( Clearaudio Wood/Essence cartridge/Modwright power amp/Vivid B1 speakers).
All the large capacitors were changed to Panasonics,Nichicon. So too were all the transistors to the relevant up to date equivalents ( more than 50 of them), the servo op amp, the volume pot to an Alps 10 Ohm rotary carbon film one, a couple of resistors( Vishays),both 7815 and 7915 regulators. All the RCA connectors and it's fittings replaced, it was a challenge as the old ones were large, could not be found and work had to be done with their modern replacements. It worked out fine in the end.
Shaun's suggestions of replacing the 20 Ohm volume pot with a 10 ohm one was indispensable as the gain was to high ( this is/was a universal problem), and I could fit sockets and play around with changing resistor values to suit my needs ( can be seen in the pics). This works and still in progress...
We had some motor-boating issues which tested our patience, over-ally it was worth all the effort, little monies and time spent, and I've been rewarded with a unit that gives and brings me great joy.
Some pics of the process till finish follows.
Finished unit, first :
There's still some work to be done, I have some ideas, but they will follow.....
Some other pics in the next post.
