Threshold CAS 1

[SamPiazza]

I found what I need!
47mfd/20V. replaced with Silmic II 25V.
220mfd/10V. replaced with Nichicon FG 10V.

 

[SamPiazza]

Schematic

I finally found a clear schematic.

 

[SamPiazza]

One of the 220mfd tantalum capacitors finally completely shorted. It was causing the DC offset voltage to be .6V.
Once I replaced all the tantalum capacitors and set the rail current at 225 mA., the CAS1 sounds great!

 

[gl]

I’m not so sure about that schematic. The driver transistors in this amplifier were Fairchild FT317 and FT417 types.

A friend owned one back in the day and traced it out. I have a copy of his schematic somewhere.

Graeme

 

[Mark Johnson]

Sam Piazza was the name of the patriarch of the shoe repair dynasty in the middle american town where I went to school. One of his female relatives was badly injured in a riding lawn mower accident.

Same guy??

 

[Nelson Pass]

One of the 220mfd tantalum capacitors finally completely shorted. It was causing the DC offset voltage to be .6V.
Once I replaced all the tantalum capacitors and set the rail current at 225 mA., the CAS1 sounds great!

Those tantalum gumdrops tended toward shorter life spans than I expected.

If you see any in a Threshold amplifier, feel free to replace them.

 

[Zen Mod]

not safe

safer sending them (amps) to OPLDF

lately we broaden our expertise to Treshold , too

 

[PKI]

look at those nicely twisted wires! Don't see those in PL stuff 🙂. They don't make them as they used to, right Nelson? HA-HA 😛

 

[operatorius]

Reviving this thread. Does anyone know if cas1 handles 4ohm load? Whats wpc with 4ohm load?

 

[Eric M]

Anyone know the current rating of the 2 internal fuses for the left and right power supply of a 120 VAC CAS 1?
The schematic of the power supply above is not what's in my CAS 1.

Thanks,

Eric M.