Is is a Selectronic? Those I have found higher than nominal. Especially if having a slightly hot mains. Please measure the AC on the transformer connector on board. If its actually circa 18VAC then sink the Mosfets and it will be OK.
Yes Selectronic, 19.4v and 19.5v (15-0-15).
No sinks by now, I've to drill them before.
I can hear the relay clicking when powering on/off, with a little delay.
Cheers 😉
No sinks by now, I've to drill them before.
I can hear the relay clicking when powering on/off, with a little delay.
Cheers 😉
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It is too high, they maybe got some 18-0-18 designated as 15-0-15. Sink at least the CCS Mosfets and it will survive well in normal 68//68 mode.
I've got 2 other toroidals : 30VA 2x15v and 80VA 2x12V.
I'll try tomorrow, too late now for testing.
The wine we drank with dinner : Pommard 1993 (Bourgogne !!!)
Hope my DCB1 will have the same taste... like flying in heaven 🙂 🙂 🙂
I'll try tomorrow, too late now for testing.
The wine we drank with dinner : Pommard 1993 (Bourgogne !!!)
Hope my DCB1 will have the same taste... like flying in heaven 🙂 🙂 🙂
CSS current
Just wondering is it ok to run with CSS below 60mA - 3 LEDs with 20mA, 2mA and 2mA...??
Just wondering is it ok to run with CSS below 60mA - 3 LEDs with 20mA, 2mA and 2mA...??
Second try with a 30VA 2x15v toroidal.
I found now -9.5 and +10.2v at the pins.
-21.7 and +21.4 at the 2x68R.
Is it better ?
Thanks
I found now -9.5 and +10.2v at the pins.
-21.7 and +21.4 at the 2x68R.
Is it better ?
Thanks
The CCS current has nothing to do with LEDS. Has only to do with the setting resistors in the 68//68 places. I would not run it below 40mA per rail.
Thanks Salas
Mosfets are a little bit hot, I think it's normal as they are not heatsinked.
What measures are required to verify that my DCB1 is Ok ?
Since the Mosfets run current, see also that you have no bad DC offset on the audio outputs and its good to play.
I have no output or input connected and I measure DC on output (L/R) and ground.
Is it the correct way to measure the DC offset ?
Is it the correct way to measure the DC offset ?
0.4 Right / 0.9 Left
I've noticed that the value is unstable, especially when breathing on the Mosfets
No heatsinks.
And now, 14mn later 0.6 Right / 1.3 Left.
Normal values ?
I've noticed that the value is unstable, especially when breathing on the Mosfets
No heatsinks.
And now, 14mn later 0.6 Right / 1.3 Left.
Normal values ?
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Very very low, and its normal to be thermally affected. Hook it up and listen, looks like a prefectly healthy build so far.
Thanks Salas for your comments and tips 🙂
I gave a try with my heatsinks, one shared for two Mosfets on the same side.
I've noticed that the 5 Leds where off while the heatsink is mounted.
Do I need to isolate the Mosfets with a pad ?
Mosfets, both 240/9240, near the 2x68R run hotter than the ones on LT7812 side.
I gave a try with my heatsinks, one shared for two Mosfets on the same side.
I've noticed that the 5 Leds where off while the heatsink is mounted.
Do I need to isolate the Mosfets with a pad ?
Mosfets, both 240/9240, near the 2x68R run hotter than the ones on LT7812 side.
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hi,
the thermal interface on the back of the mosFET is connected to the Drain of the mosFET.
If you connect a common plate/heatsink across two of them, you have effectively connected the two drains together.
At least on FET must be electrically insulated.
The one that needs to dissipate less heat can have a mica or insulating washer fitted. The higher dissipating FET can be bolted direct for better heat transfer.
the thermal interface on the back of the mosFET is connected to the Drain of the mosFET.
If you connect a common plate/heatsink across two of them, you have effectively connected the two drains together.
At least on FET must be electrically insulated.
The one that needs to dissipate less heat can have a mica or insulating washer fitted. The higher dissipating FET can be bolted direct for better heat transfer.
Hi Andrew
Thank you for the good advice, I'll try it tomorrow.
No dammage at all, the Mosfets are safe.
🙂
Edit
Finally I haven't wait tomorrow?
Cooler Mosfets have been electrically insulated, result is Ok.
Thank you for the good advice, I'll try it tomorrow.
No dammage at all, the Mosfets are safe.
🙂
Edit
Finally I haven't wait tomorrow?
Cooler Mosfets have been electrically insulated, result is Ok.
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They have even survived a 36V short time same type zap early in the phono thread by a member when running at 200mA in this type of reg.
Yes Salas, very very short time, they are still alive and kicking !
With the heatsinks, DC offset is lower, after 20mn : 0.4 Right / 0.7 Left.
Maybe I'll be abble to try the DCB1 tomorrow... 🙂
With the heatsinks, DC offset is lower, after 20mn : 0.4 Right / 0.7 Left.
Maybe I'll be abble to try the DCB1 tomorrow... 🙂
