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Arfa Daily
May 16, 2012, 9:07:36 PM5/16/12
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Hi all
The amp chassis from what I think is a 1478-85 has fetched up on my bench
for checking / repair. Can anyone tell me what the AC input voltage from the
power transformer for the HT supply is, please ? I've found several copies
of the schematics on line, but none of them are clear enough to be able to
read the AC input voltage for the HT supply. Needless to say, the obvious
one of 6.3v AC for the heaters is clearly visible ... :-\
Once I know approx what voltage I am looking for, I should have a suitable
transformer knocking around the workshop to get it going enough for testing.
TIA
Arfa
The amp chassis from what I think is a 1478-85 has fetched up on my bench
for checking / repair. Can anyone tell me what the AC input voltage from the
power transformer for the HT supply is, please ? I've found several copies
of the schematics on line, but none of them are clear enough to be able to
read the AC input voltage for the HT supply. Needless to say, the obvious
one of 6.3v AC for the heaters is clearly visible ... :-\
Once I know approx what voltage I am looking for, I should have a suitable
transformer knocking around the workshop to get it going enough for testing.
TIA
Arfa
lino...@yahoo.com
May 17, 2012, 10:56:50 PM5/17/12
to
Arfa R-O used a voltage doubler circuit and the plates of the 6973's were supposed to have approx 360 VDC. So that would indicate that an AC input around 150-160 VAC.
I converted a power supply for one of those phono's to mate with a 1465's amp which had it's own B+ tran but would otherwise have mated. Luckily i examined the P.S. unit before connecting it.
Rob/NYC
I converted a power supply for one of those phono's to mate with a 1465's amp which had it's own B+ tran but would otherwise have mated. Luckily i examined the P.S. unit before connecting it.
Rob/NYC
Arfa Daily
May 18, 2012, 12:40:49 PM5/18/12
to
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> On Wednesday, May 16, 2012 8:07:36 PM UTC-5, Arfa Daily wrote:
>> Hi all
>>
>> The amp chassis from what I think is a 1478-85 has fetched up on my bench
>> for checking / repair. Can anyone tell me what the AC input voltage from
>> the
>> power transformer for the HT supply is, please ? I've found several
>> copies
>> of the schematics on line, but none of them are clear enough to be able
>> to
>> read the AC input voltage for the HT supply. Needless to say, the obvious
>> one of 6.3v AC for the heaters is clearly visible ... :-\
>>
>> Once I know approx what voltage I am looking for, I should have a
>> suitable
>> transformer knocking around the workshop to get it going enough for
>> testing.
>>
>> TIA
>>
>> Arfa
>
>
<lino...@yahoo.com> wrote in message
>
>
>
>
>
> On Wednesday, May 16, 2012 8:07:36 PM UTC-5, Arfa Daily wrote:
>> Hi all
>>
>> The amp chassis from what I think is a 1478-85 has fetched up on my bench
>> for checking / repair. Can anyone tell me what the AC input voltage from
>> the
>> power transformer for the HT supply is, please ? I've found several
>> copies
>> of the schematics on line, but none of them are clear enough to be able
>> to
>> read the AC input voltage for the HT supply. Needless to say, the obvious
>> one of 6.3v AC for the heaters is clearly visible ... :-\
>>
>> Once I know approx what voltage I am looking for, I should have a
>> suitable
>> transformer knocking around the workshop to get it going enough for
>> testing.
>>
>> TIA
>>
>> Arfa
>
>
news:1f25892b-bb23-4c10...@googlegroups.com...
> Arfa R-O used a voltage doubler circuit and the plates of the 6973's were
> supposed to have approx 360 VDC. So that would indicate that an AC input
> around 150-160 VAC.
>
> I converted a power supply for one of those phono's to mate with a 1465's
> amp which had it's own B+ tran but would otherwise have mated. Luckily i
> examined the P.S. unit before connecting it.
>
>
> Rob/NYC
Ah. Interesting. Thanks for that Rob. Looking again at the (very poor)
> supposed to have approx 360 VDC. So that would indicate that an AC input
> around 150-160 VAC.
>
> I converted a power supply for one of those phono's to mate with a 1465's
> amp which had it's own B+ tran but would otherwise have mated. Luckily i
> examined the P.S. unit before connecting it.
>
>
> Rob/NYC
schematic that I have, you are indeed correct. I hadn't taken too much
notice of where the winding went when it got inside the amp chassis, other
than it going to four metal top hat reccies, which I assumed were just a
standard bridge, but in fact one end of the winding goes to the centre point
of two electrolytics hanging in series between rail and ground, and the
diodes are in fact in two series pairs. Now I'm looking at the schematic
again with a view to the winding being 150 V, it does actually look like I
can see "150 VAC" struggling up out of the pixellated mess that is the scan
...
Cheers for the heads up. You might just have saved a nasty 'accident' with
it ... d;~}
Arfa
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