Need help to identify op amps in DACT CT-100 phono stage

[richloh]

Searched mouser and digikey ... even 2200uf 25v at minimum 12mm diameter which makes them impossible to be used 😪

Max of 470uf for 25v at same 8mm diameter 🤒

 

[rayma]

Hey Rayma, Oops ... yes, thanks for the reminder .. will measure b4 removal 🙏🙏

More importantly, don't power the circuit unless the capacitors in place.
It won't work properly, and further damage could be caused.

Suggest that you use DIgikey's tool to characterize the capacitor needed, that is much easier.
https://www.digikey.com/en/products/filter/aluminum-electrolytic-capacitors/58

 

[richloh]

Suspected root cause being cap is due to about 10 secs from cold start being fine but distorts thereafter. What I cannot comprehene is that this is dual mono and strange that responsible component(s) fails for both channels .. with ICs especially remote. Just hope that it is batch issue or simply nature of especially organic caps from Oscon to fail all at once due to being used and then store for exceptional 8 long yrs.

Cheers 🤞🤞

Hi, any thought on the abovementioned ?

Cheers.

 

[rayma]

The circuit topology is:
flat amplifier --> passive RIAA --> flat amplifier

But without the schematic, there's not much point to theorize.
You could signal trace the bad channel.

Perhaps a bad solder joint opens when it warms up.
This is not unusual for older SMT construction.

 

[richloh]

Hi Rayma,

But a bit strange for both dual mono channels to be affected at the same time for same distortion ?

Cheers.

 

[rayma]

If it is indeed dual mono, are there dual mono power input connectors? Appears to be.

Most likely problem in older pcbs like this, is poor solder connections.
Static electricity damage due to improper storage or handling is also possible.

 

[his047]

I bought an NLE17 in 1998. I always kept it switched on but it failed some 10 years ago because I foolishly disconnected the power connector that I used while the power-supply was still live: never do that! Switch off at wall before disconnecting.
Fortunately, Niels lives round the corner where I was a child and he graciously repaired and rebuilt the rather messy unit I had constructed. It still outperforms every Phonoamp that I know.

 

[richloh]

Lucky you ! 🥳🥳

My unit is otw to DACT Denmark c/o Allan for swap at very reasonable $ and will probably also end up with Neil 😅

For me, almost close to perfect matching to any cartridges due to available settings is what sets it apart and is only beaten by 5x $ of aurorasound's vida lcr phono with settings customised to my cartridges that I am also having for dual TT setup:

https://highend-electronics.com/products/aurorasound-vida-vinyl-disk-amplifier

Cheers