My vintage Threshold Stasis 3 runs cold. I understand that this is a known issue with this design. I have seen references to a revised bias circuit. Anyone have experience with this? Anyone have details or a schematic for this modification?
The bias circuit in the amplifier has an adjustment pot which was designed so
that wiper failure puts the bias low. (Don't laugh, I have seen a lot of
examples where failure throws the bias high)
.
However, it is very unlikely that both channels would do that. More likely is
that someone adjusted the channels low.
😎
that wiper failure puts the bias low. (Don't laugh, I have seen a lot of
examples where failure throws the bias high)
. However, it is very unlikely that both channels would do that. More likely is
that someone adjusted the channels low.
😎
The bias circuit in the amplifier has an adjustment pot which was designed so
that wiper failure puts the bias low. (Don't laugh, I have seen a lot of
examples where failure throws the bias high)
Isn't that the case with most FW products? If the pots on e.g. F5 are open I would expect smoke...
Or is pot failure typically a short?
That is true of the F5 , but there is not an obvious mechanism for doing it
otherwise.
😎
Left channel runs cold!
Hi. I have just received a pristine Stasis 3 - unopened! There is no sign of service or anything but dust down there... Outside is flawless!
But; the amp is running cold, very cold on left channel. Right channel became as hot as I can hardly notice with my hand.
* The amplifier is not much used regarding seller and with this temp conditions - is there necessary to change caps?
* Where is the voltage checkpoint for setting bias?
* The left channel is totally cold - is that the adjust pot or a dried cap around bias Components?
And a funny thing; I discovered a production fault; right channel input makes the left channel LED's to move.... and noone has been in there...... 😀
Greetings from Norway!
Hi. I have just received a pristine Stasis 3 - unopened! There is no sign of service or anything but dust down there... Outside is flawless!
But; the amp is running cold, very cold on left channel. Right channel became as hot as I can hardly notice with my hand.
* The amplifier is not much used regarding seller and with this temp conditions - is there necessary to change caps?
* Where is the voltage checkpoint for setting bias?
* The left channel is totally cold - is that the adjust pot or a dried cap around bias Components?
And a funny thing; I discovered a production fault; right channel input makes the left channel LED's to move.... and noone has been in there...... 😀
Greetings from Norway!
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Yes, when I put right channel from preamp to the right side of the amp (seen from the front) i got signal on left channel leds. I now see that right side of amp is left channel....
Confusing.....
But no Production fault! 🙂
Confusing.....
But no Production fault! 🙂
Some pictures of a pristine Stasis 3
Dark photos....
The amp beneath Stasis 3 is a DIY A40 - sounds wonderful!
Dark photos....
The amp beneath Stasis 3 is a DIY A40 - sounds wonderful!
Attachments
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Nice pictures! Nice amp!
How are the outputs connected to the heatsink? I see a 1 cm gap between the outputboard and the heatsinks?
How are the outputs connected to the heatsink? I see a 1 cm gap between the outputboard and the heatsinks?
Thanks!
There are 8 outputs in the bottom also, totally 16 each channel. Between them there is solid alluminium bolted to the heatsink.
Wonderful craftmanship!
There are 8 outputs in the bottom also, totally 16 each channel. Between them there is solid alluminium bolted to the heatsink.
Wonderful craftmanship!
re-set the bias on both channels , and enjoy
if there is no buzz or hum , don't think about recapping ..... yet
(even if I would dismantle it in pieces right away)
if there is no buzz or hum , don't think about recapping ..... yet
(even if I would dismantle it in pieces right away)
Resetting bias; do I understand correctly first adjust for 75mV on one of 0.68R resistors and then fine-adjust for 42gC (+-2gC) on heatsinks?
No buzz, hum or bump (on/off)
Even now - almost cold - I like the sound very much!
No buzz, hum or bump (on/off)
Even now - almost cold - I like the sound very much!
Biased amp today. 40,2 and 40,3gC with cover in place. 2mv dc right channel and 45mv dc left.
The amp sounds fantastic! Big crispy "want to play more" sound. Easy to listen to. I am a SET tube addict, but this amp do almost everything what SET do and is much better where SET is not so good. It has this tube-like sound in a good way.
This amp can play loud without pushing ears. It is easy to follow instruments and se instruments places i the sound picture. This transistor amp have the inne resolution known from Telefunken ECC803S. Some will know what I meen, an some do not have a clue...
This amp will stay! Feeding a pair of Tannoy studiomonitor with HPD 315A - and it is a match made in heaven!
The amp sounds fantastic! Big crispy "want to play more" sound. Easy to listen to. I am a SET tube addict, but this amp do almost everything what SET do and is much better where SET is not so good. It has this tube-like sound in a good way.
This amp can play loud without pushing ears. It is easy to follow instruments and se instruments places i the sound picture. This transistor amp have the inne resolution known from Telefunken ECC803S. Some will know what I meen, an some do not have a clue...
This amp will stay! Feeding a pair of Tannoy studiomonitor with HPD 315A - and it is a match made in heaven!
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