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From: N_Cook on 28 Oct 2009 06:30
According to owner , bought it off company rep a few years ago and is export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac (4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but 3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps anywhere ?


From: Gareth Magennis on 28 Oct 2009 07:08

"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hc96gi$2gh$1(a)news.eternal-september.org...
> According to owner , bought it off company rep a few years ago and is
> export
> version prototype.
> Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
> cap?) but excessive hum.
> 450V rating ps electros but I measure 488V on the HT rail and varying ac
> (4
> to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
> 3
> in there, I've not taken apart yet.
> The neon lit mains switch looks more like a light bulb , runs too hot to
> keep your finger on, I suspect droppers for USA mains inside. No serial
> number on the chassis. Have yet to test the valves but I suspect probably
> ok, any advice on dealing with the HT/caps issue? What is the HT rail
> supposed to be for USA issue ones ? Any schematic for the pa / ps anywhere
> ?
>
>



What is the voltage on the heaters? If this is excessive then the whole
transformer is probably running too high.



Gareth.


From: N_Cook on 28 Oct 2009 08:35
Gareth Magennis <sound.service(a)btconnect.com> wrote in message
news:eNidnRX80fKnunXXnZ2dnUVZ8j2dnZ2d(a)bt.com...
>
> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> news:hc96gi$2gh$1(a)news.eternal-september.org...
> > According to owner , bought it off company rep a few years ago and is
> > export
> > version prototype.
> > Blew a fuse a few weeks back , runs still ,after fuse change (self
heeled
> > cap?) but excessive hum.
> > 450V rating ps electros but I measure 488V on the HT rail and varying ac
> > (4
> > to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
but
> > 3
> > in there, I've not taken apart yet.
> > The neon lit mains switch looks more like a light bulb , runs too hot
to
> > keep your finger on, I suspect droppers for USA mains inside. No serial
> > number on the chassis. Have yet to test the valves but I suspect
probably
> > ok, any advice on dealing with the HT/caps issue? What is the HT rail
> > supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere
> > ?
> >
> >
>
>
>
> What is the voltage on the heaters? If this is excessive then the whole
> transformer is probably running too high.
>
>
>
> Gareth.
>
>

I didn't think of that, all valves out for testing at the moment

No mains voltage stated at the IEC inlet, just fuses for 110 or 240V, 7
wires to the primary side of the tranformer and jumper spade matrix inside.
As the rep was going around Europe , not just the UK , I wonder if if it is
internally set to 210V.
Anyone know what the secondary voltages should be ? or how to unravel ?
power up and look for voltages 30 or 40 V off from 0,110 or 240 I suppose.
No smoothing choke for this amp it would seem, unless its in with the mains
transformer .

As the mains switch is made for 110V use then anything is possible



From: N_Cook on 28 Oct 2009 08:44
Meat Plow <meat(a)petitmorte.net> wrote in message
news:3863ce.crm.17.2(a)news.alt.net...
> On Wed, 28 Oct 2009 10:30:08 -0000, "N_Cook" <diverse(a)tcp.co.uk>wrote:
>
> >According to owner , bought it off company rep a few years ago and is
export
> >version prototype.
> >Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
> >cap?) but excessive hum.
> >450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
> >to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
3
> >in there, I've not taken apart yet.
> >The neon lit mains switch looks more like a light bulb , runs too hot to
> >keep your finger on, I suspect droppers for USA mains inside. No serial
> >number on the chassis. Have yet to test the valves but I suspect probably
> >ok, any advice on dealing with the HT/caps issue? What is the HT rail
> >supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere ?
> >
>
> The HT would depend on what tubes were in the output. The mains switch
> illumination is derived from where?
>
> I've seen HT from 400 to 700 volts depending on the tube and
> manufacturer but if you have 450v caps your HT should be what minus 10
> to 15% of the 450v caps..
>
> What are the tube heater voltages?

Testing the valves at the moment , next time I power up I will use a variac
set for 210V or so and try and work out the 0/110/210/230 settings


From: Gareth Magennis on 28 Oct 2009 19:03

"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hc9dr9$v2o$1(a)news.eternal-september.org...
> Gareth Magennis <sound.service(a)btconnect.com> wrote in message
> news:eNidnRX80fKnunXXnZ2dnUVZ8j2dnZ2d(a)bt.com...
>>
>> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
>> news:hc96gi$2gh$1(a)news.eternal-september.org...
>> > According to owner , bought it off company rep a few years ago and is
>> > export
>> > version prototype.
>> > Blew a fuse a few weeks back , runs still ,after fuse change (self
> heeled
>> > cap?) but excessive hum.
>> > 450V rating ps electros but I measure 488V on the HT rail and varying
>> > ac
>> > (4
>> > to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
> but
>> > 3
>> > in there, I've not taken apart yet.
>> > The neon lit mains switch looks more like a light bulb , runs too hot
> to
>> > keep your finger on, I suspect droppers for USA mains inside. No serial
>> > number on the chassis. Have yet to test the valves but I suspect
> probably
>> > ok, any advice on dealing with the HT/caps issue? What is the HT rail
>> > supposed to be for USA issue ones ? Any schematic for the pa / ps
> anywhere
>> > ?
>> >
>> >
>>
>>
>>
>> What is the voltage on the heaters? If this is excessive then the whole
>> transformer is probably running too high.
>>
>>
>>
>> Gareth.
>>
>>
>
> I didn't think of that, all valves out for testing at the moment
>
> No mains voltage stated at the IEC inlet, just fuses for 110 or 240V, 7
> wires to the primary side of the tranformer and jumper spade matrix
> inside.
> As the rep was going around Europe , not just the UK , I wonder if if it
> is
> internally set to 210V.
> Anyone know what the secondary voltages should be ? or how to unravel ?
> power up and look for voltages 30 or 40 V off from 0,110 or 240 I suppose.
> No smoothing choke for this amp it would seem, unless its in with the
> mains
> transformer .
>
> As the mains switch is made for 110V use then anything is possible
>
>
>


Your best bet IMHO is trying to get the 6.3v heater winding correct via a
variac and then make a judgement.



Gareth.

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