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From: N_Cook on 8 Mar 2010 03:23
As far as I can tell this is the basic form to the power amp - what class is
it? and in general terms the operational bounds of the biasing, a lot of
diodes? seem to be involved.
Equi-spaced font needed for this ASCII, maybe properties/mesage details or
copied into text handler with "Terminal ","Fixedsys" font or similar
(only 2 emitter resistors, on two central Tr and chokes in the other emitter
commoned connections, all left out in the below )

---------------------- + rail
| |
|/ \|
-| |-
|> <|
| |
|--------| all 2SD2560
|
\|
|-
<|
|
|---------- O/P
|
>|
|-
/|
|
|--|----| all 2SA1647
| |
|< >|
-| |-
|\ /|
| |
--------------------- - rail





From: Mark Zacharias on 8 Mar 2010 05:21
"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hn2c4v$855$1(a)news.eternal-september.org...
> As far as I can tell this is the basic form to the power amp - what class
> is
> it? and in general terms the operational bounds of the biasing, a lot of
> diodes? seem to be involved.
> Equi-spaced font needed for this ASCII, maybe properties/mesage details or
> copied into text handler with "Terminal ","Fixedsys" font or similar
> (only 2 emitter resistors, on two central Tr and chokes in the other
> emitter
> commoned connections, all left out in the below )
>
> ---------------------- + rail
> | |
> |/ \|
> -| |-
> |> <|
> | |
> |--------| all 2SD2560
> |
> \|
> |-
> <|
> |
> |---------- O/P
> |
> >|
> |-
> /|
> |
> |--|----| all 2SA1647
> | |
> |< >|
> -| |-
> |\ /|
> | |
> --------------------- - rail
>
>
>
>
>


Looks like a lot of amps I see these days. Don't know for sure the "class"
but I suspect it's pretty conventional AB.

Those outputs are Darlington, by the way, so obviously there's an additional
1.2 volts to be accounted for in the biasing...

Mark Z.

From: N_Cook on 8 Mar 2010 05:58
Mark Zacharias <mark_zacharias(a)sbclobal.net> wrote in message
news:4b94cfb6$0$2226$c3e8da3(a)news.astraweb.com...
> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> news:hn2c4v$855$1(a)news.eternal-september.org...
> > As far as I can tell this is the basic form to the power amp - what
class
> > is
> > it? and in general terms the operational bounds of the biasing, a lot of
> > diodes? seem to be involved.
> > Equi-spaced font needed for this ASCII, maybe properties/mesage details
or
> > copied into text handler with "Terminal ","Fixedsys" font or similar
> > (only 2 emitter resistors, on two central Tr and chokes in the other
> > emitter
> > commoned connections, all left out in the below )
> >
> > ---------------------- + rail
> > | |
> > |/ \|
> > -| |-
> > |> <|
> > | |
> > |--------| all 2SD2560
> > |
> > \|
> > |-
> > <|
> > |
> > |---------- O/P
> > |
> > >|
> > |-
> > /|
> > |
> > |--|----| all 2SA1647
> > | |
> > |< >|
> > -| |-
> > |\ /|
> > | |
> > --------------------- - rail
> >
> >
> >
> >
> >
>
>
> Looks like a lot of amps I see these days. Don't know for sure the "class"
> but I suspect it's pretty conventional AB.
>
> Those outputs are Darlington, by the way, so obviously there's an
additional
> 1.2 volts to be accounted for in the biasing...
>
> Mark Z.
>

Assuming its rating at 200 watts into 4 Ohms is per (non stereo) channel ,
it does not seem right that all that current goes through 2 output TOP66
devices. I've not found any date so far, mixer section not looked at yet.
Does roundel stamp on the [cb with Japanese script on top and bottom
sections and 86 12 15 across the middle mean 1986?


From: Mark Zacharias on 8 Mar 2010 06:49
"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hn2l82$mq2$1(a)news.eternal-september.org...
> Mark Zacharias <mark_zacharias(a)sbclobal.net> wrote in message
> news:4b94cfb6$0$2226$c3e8da3(a)news.astraweb.com...
>> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
>> news:hn2c4v$855$1(a)news.eternal-september.org...
>> > As far as I can tell this is the basic form to the power amp - what
> class
>> > is
>> > it? and in general terms the operational bounds of the biasing, a lot
>> > of
>> > diodes? seem to be involved.
>> > Equi-spaced font needed for this ASCII, maybe properties/mesage details
> or
>> > copied into text handler with "Terminal ","Fixedsys" font or similar
>> > (only 2 emitter resistors, on two central Tr and chokes in the other
>> > emitter
>> > commoned connections, all left out in the below )
>> >
>> > ---------------------- + rail
>> > | |
>> > |/ \|
>> > -| |-
>> > |> <|
>> > | |
>> > |--------| all 2SD2560
>> > |
>> > \|
>> > |-
>> > <|
>> > |
>> > |---------- O/P
>> > |
>> > >|
>> > |-
>> > /|
>> > |
>> > |--|----| all 2SA1647
>> > | |
>> > |< >|
>> > -| |-
>> > |\ /|
>> > | |
>> > --------------------- - rail
>> >
>> >
>> >
>> >
>> >
>>
>>
>> Looks like a lot of amps I see these days. Don't know for sure the
>> "class"
>> but I suspect it's pretty conventional AB.
>>
>> Those outputs are Darlington, by the way, so obviously there's an
> additional
>> 1.2 volts to be accounted for in the biasing...
>>
>> Mark Z.
>>
>
> Assuming its rating at 200 watts into 4 Ohms is per (non stereo) channel ,
> it does not seem right that all that current goes through 2 output TOP66
> devices. I've not found any date so far, mixer section not looked at yet.
> Does roundel stamp on the [cb with Japanese script on top and bottom
> sections and 86 12 15 across the middle mean 1986?
>
>

The B1647 and C2560 are pretty high-rated devices. 200 into 4 ohms doesn't
seem _too_ over rated to me.

I commonly see them in consumer audio in their higher end model surround
receivers, that is the ones rated over the standard 100 per channel, more
like 120 into 8 ohms. So as I say, 200 doesn't seem too far off, perhaps
just a bit of a stretch.

Mark Z.

From: N_Cook on 8 Mar 2010 08:06
Mark Zacharias <mark_zacharias(a)sbclobal.net> wrote in message
news:4b94e43f$0$24357$c3e8da3(a)news.astraweb.com...
> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> news:hn2l82$mq2$1(a)news.eternal-september.org...
> > Mark Zacharias <mark_zacharias(a)sbclobal.net> wrote in message
> > news:4b94cfb6$0$2226$c3e8da3(a)news.astraweb.com...
> >> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> >> news:hn2c4v$855$1(a)news.eternal-september.org...

> >>
> >
> > Assuming its rating at 200 watts into 4 Ohms is per (non stereo) channel
,
> > it does not seem right that all that current goes through 2 output TOP66
> > devices. I've not found any date so far, mixer section not looked at
yet.
> > Does roundel stamp on the [cb with Japanese script on top and bottom
> > sections and 86 12 15 across the middle mean 1986?
> >
> >
>
> The B1647 and C2560 are pretty high-rated devices. 200 into 4 ohms doesn't
> seem _too_ over rated to me.
>
> I commonly see them in consumer audio in their higher end model surround
> receivers, that is the ones rated over the standard 100 per channel, more
> like 120 into 8 ohms. So as I say, 200 doesn't seem too far off, perhaps
> just a bit of a stretch.
>
> Mark Z.
>

All power devices share the same h/s 6 of these per ch, bridge rect,
7815,7915 no special treatment for those final 2 per ch. No fan assist,
large convection area out rear only. Get into the mixer later for 7 more
problems in there, so probably will find a more reliable date


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