Anybody who can confirm the secondary output of the transformer?
Is it 2x 37VAC or 2x 33VAC
even though it's 33vac or 37vac, it's still way high for the 35v caps, at 33vac= 46.6vdc, 37vac = 52vdc. So if you have 35volts filter caps it will blow up and also to high for those regulator inputs...good if they still survives..
Definitely, no designer will put a 35v cap lower than the rated supply rails....
Hi Junm,
There might be some confusions...
I believed that those small caps is not getting power from the main caps. but on the secondaries. They have they own small diodes. Here's what I observed.
CASE 1--> Main Caps 63v rating
If the supply is 37VAC, im getting 24volts DC on the MAIN big caps.
This is the supply of the transistors, unregulated.
I dont have issues on this even if I lower it to 33VAC.
CASE 2--> On the SMALL CAPS 35v ratings:
If the supply is 37VAC, im getting 35volts DC on the small caps.
This supplies the regulators for pre-amp, tone section, processors etc etc etc.
This is BAD coz those caps are getting their max voltages.
This is what I ment that 37VAC is definitely WRONG, but should be lower.
Probably if 33VAC, I would get 30vDC on these caps. Safe, right? and they are cool.
You would ask, what made me think it's 33VAC? I've seen some sematics by thule audio using this 2x 33VAC.
And you would ask why the installed transformer is 37VAC?, here's the answer.
1) Its indicated at the back panel about its power input, it says : 230VAC
2) But inside the transformer is PRI: 100VAC SEC: 2x 37VAC
How did this happen?
3) It also says Made in Denmark, but this unit came from Japan.
I would conclude it originated from Denmark, shipped to Japan and the Japs changed the trafo to fit into their main AC supply which is 100VAC. Unfortunately the secondary was high. Probably this wrong trafo is the only one available.
That's the reason I'm confirming if the original secondary is 33VAC so I can modify or reduce the secondary windings of the trafo.
There might be some confusions...
I believed that those small caps is not getting power from the main caps. but on the secondaries. They have they own small diodes. Here's what I observed.
CASE 1--> Main Caps 63v rating
If the supply is 37VAC, im getting 24volts DC on the MAIN big caps.
This is the supply of the transistors, unregulated.
I dont have issues on this even if I lower it to 33VAC.
CASE 2--> On the SMALL CAPS 35v ratings:
If the supply is 37VAC, im getting 35volts DC on the small caps.
This supplies the regulators for pre-amp, tone section, processors etc etc etc.
This is BAD coz those caps are getting their max voltages.
This is what I ment that 37VAC is definitely WRONG, but should be lower.
Probably if 33VAC, I would get 30vDC on these caps. Safe, right? and they are cool.
You would ask, what made me think it's 33VAC? I've seen some sematics by thule audio using this 2x 33VAC.
And you would ask why the installed transformer is 37VAC?, here's the answer.
1) Its indicated at the back panel about its power input, it says : 230VAC
2) But inside the transformer is PRI: 100VAC SEC: 2x 37VAC
How did this happen?
3) It also says Made in Denmark, but this unit came from Japan.
I would conclude it originated from Denmark, shipped to Japan and the Japs changed the trafo to fit into their main AC supply which is 100VAC. Unfortunately the secondary was high. Probably this wrong trafo is the only one available.
That's the reason I'm confirming if the original secondary is 33VAC so I can modify or reduce the secondary windings of the trafo.
i checked the schematics of abx10....i think its 37vac as indicated on your trafo. and those regulators are with separate rectifiers that i think in doubler mode. ABX10 and Mkii maybe common on power section so make it a reference.
Yeah I believed its 37VAC... same as its older sister their amp section is getting 24vDC. They only diffrer in the preamp section the MKII is 2volts higher.
When I tried to lower that 37VAC that I would get as low as 22vDC on the amp section, the relay shuts downs at peak levels, its under voltage.
I will just replace the small caps from 35V to maybe 50V coz their are supplied with their max capacity and install a fan inside to prevent overheating on those regulators.
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