Using Dynakit ST70 in the UK
 

Hi, I have been offline from this group for a while, but would
appreciate some advice on restoring a stock Dynaco ST70 for use in the
UK. Thanks, David

Using Dynakit ST70 in the UK
 

"dah" wrote in message
oups.com...
Hi, I have been offline from this group for a while, but would
appreciate some advice on restoring a stock Dynaco ST70 for use in the
UK. Thanks, David



David is one of my 'offroaders' and offlist I have pointed him to a stepdown
trannie for his 117 Volt Dynaco ST70, mentioned above:

http://www.eurobatteries.com/sitepag...tors-ac-ac.asp


Does anyone here know of any drawbacks or why one of these might not be
suitable for audio use? (I have never used one myself - my Dynacos being
240V....)

My thinking is that it would allow him to retain his original (I hope)
Dynaco power supply trannie...???

(Note the clever 'Brit plug/Yank socket' arrangement on the 16 quid model -
very handy for anyone with similar Yank kit with original power cables/plugs
on it...!!)

Using Dynakit ST70 in the UK
 

"Keith G" wrote in message
...

"dah" wrote in message
oups.com...
Hi, I have been offline from this group for a while, but would
appreciate some advice on restoring a stock Dynaco ST70 for use in the
UK. Thanks, David



David is one of my 'offroaders' and offlist I have pointed him to a
stepdown trannie for his 117 Volt Dynaco ST70, mentioned above:

http://www.eurobatteries.com/sitepag...tors-ac-ac.asp


Does anyone here know of any drawbacks or why one of these might not be
suitable for audio use? (I have never used one myself - my Dynacos being
240V....)

My thinking is that it would allow him to retain his original (I hope)
Dynaco power supply trannie...???

(Note the clever 'Brit plug/Yank socket' arrangement on the 16 quid
model - very handy for anyone with similar Yank kit with original power
cables/plugs on it...!!)

**Forget the 16 Squid model. Not enough grunt. The ST500 should do the trick
though. Other than that, step-down trannies pose no real problems. As with
most things in life, the bigger the better.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

Using Dynakit ST70 in the UK
 

In article ,
Keith G wrote:
Hi, I have been offline from this group for a while, but would
appreciate some advice on restoring a stock Dynaco ST70 for use in the
UK. Thanks, David



David is one of my 'offroaders' and offlist I have pointed him to a
stepdown trannie for his 117 Volt Dynaco ST70, mentioned above:

http://www.eurobatteries.com/sitepag...tors-ac-ac.asp


Does anyone here know of any drawbacks or why one of these might not be
suitable for audio use? (I have never used one myself - my Dynacos being
240V....)

My thinking is that it would allow him to retain his original (I hope)
Dynaco power supply trannie...???

(Note the clever 'Brit plug/Yank socket' arrangement on the 16 quid
model - very handy for anyone with similar Yank kit with original power
cables/plugs on it...!!)

An auto transformer will be fine - but make sure it is adequately rated
for the mains power *consumption* of the amp - not its nominal power
output. The power consumption on a UK device is normally on a plate
somewhere - can't speak for others.

For audio use this range which uses toroidal transformers with minimal
external magnetic field might be attractive.

http://www.tlc-direct.co.uk/Main_Ind...ter/index.html

--
*Change is inevitable, except from a vending machine*

Dave Plowman London SW
To e-mail, change noise into sound.

Using Dynakit ST70 in the UK
 

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
Hi, I have been offline from this group for a while, but would
appreciate some advice on restoring a stock Dynaco ST70 for use in the
UK. Thanks, David



David is one of my 'offroaders' and offlist I have pointed him to a
stepdown trannie for his 117 Volt Dynaco ST70, mentioned above:

http://www.eurobatteries.com/sitepag...tors-ac-ac.asp


Does anyone here know of any drawbacks or why one of these might not be
suitable for audio use? (I have never used one myself - my Dynacos being
240V....)

My thinking is that it would allow him to retain his original (I hope)
Dynaco power supply trannie...???

(Note the clever 'Brit plug/Yank socket' arrangement on the 16 quid
model - very handy for anyone with similar Yank kit with original power
cables/plugs on it...!!)

An auto transformer will be fine - but make sure it is adequately rated
for the mains power *consumption* of the amp - not its nominal power
output. The power consumption on a UK device is normally on a plate
somewhere - can't speak for others.

For audio use this range which uses toroidal transformers with minimal
external magnetic field might be attractive.

http://www.tlc-direct.co.uk/Main_Ind...ter/index.html



They are actually the wrong way round - step down is what's needed. (US amp
on UK mains.)

The step down range looks good:

http://www.tlc-direct.co.uk/Main_Ind...mer/index.html

But I've no idea what loading would be required - if the price approached
that of a replacement 240V power tranny it would arguably be not worth the
bother..??

Using Dynakit ST70 in the UK
 

In article , Keith G
wrote:


But I've no idea what loading would be required - if the price
approached that of a replacement 240V power tranny it would arguably be
not worth the bother..??


Can't comment on a specific transformer, but I can add a point to bear in
mind.

As well as the difference in mains voltage, the UK uses 50Hz, not 60Hz.
This means that the smoothing in the PSU has to cope with longer periods
between mains waveform peaks. So check carefully that the result is not a
noticable increase in hum/buzz. I suspect it will be fine as the design is
well regarded, but it may be worth keeping the possibility in mind.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Using Dynakit ST70 in the UK
 

In article ,
Keith G wrote:
For audio use this range which uses toroidal transformers with minimal
external magnetic field might be attractive.

http://www.tlc-direct.co.uk/Main_Ind...ter/index.html



They are actually the wrong way round - step down is what's needed. (US
amp on UK mains.)

Oops. ;-)

The step down range looks good:

http://www.tlc-direct.co.uk/Main_Ind...mer/index.html

Yup - they're also toroidal.

But I've no idea what loading would be required - if the price
approached that of a replacement 240V power tranny it would arguably be
not worth the bother..??

It might also be economic to have the existing transformer re-wound or
another made to the spec.

--
*The most wasted day of all is one in which we have not laughed.*

Dave Plowman London SW
To e-mail, change noise into sound.

Using Dynakit ST70 in the UK
 

"Jim Lesurf" wrote in message
...
In article , Keith G
wrote:


But I've no idea what loading would be required - if the price
approached that of a replacement 240V power tranny it would arguably be
not worth the bother..??


Can't comment on a specific transformer, but I can add a point to bear in
mind.

As well as the difference in mains voltage, the UK uses 50Hz, not 60Hz.
This means that the smoothing in the PSU has to cope with longer periods
between mains waveform peaks. So check carefully that the result is not a
noticable increase in hum/buzz. I suspect it will be fine as the design is
well regarded, but it may be worth keeping the possibility in mind.




Good point, but I suspect they have/had all bases covered - my Mk III
monoblocs (240V UK version) have '117 VOLTS 50/60~' actually printed on the
chassises's/es and there's certainly no hum, unless I tweak the biasing way
off!!

Using Dynakit ST70 in the UK
 

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
For audio use this range which uses toroidal transformers with minimal
external magnetic field might be attractive.

http://www.tlc-direct.co.uk/Main_Ind...ter/index.html



They are actually the wrong way round - step down is what's needed. (US
amp on UK mains.)

Oops. ;-)

The step down range looks good:

http://www.tlc-direct.co.uk/Main_Ind...mer/index.html

Yup - they're also toroidal.

But I've no idea what loading would be required - if the price
approached that of a replacement 240V power tranny it would arguably be
not worth the bother..??

It might also be economic to have the existing transformer re-wound or
another made to the spec.



Yes indeed, but if it wuz mine I'd strive to retain the original tranny
otherwise it'll end up like a Riley Pathfinder with a Mondeo engine in it -
might make a lot of sense, but who TF would want it?

Anyway, judging by the pix I was sent:

http://www.apah69.dsl.pipex.com/show/ST70-1.JPG

http://www.apah69.dsl.pipex.com/show/ST70-2.JPG


It looks like it's well rusted in anyway!! :-))

Using Dynakit ST70 in the UK
 

In article . com,
dah wrote:

Thanks for the advice. I couldn't access a computer this morning and
ended up getting a Maplins 200VA transformer. It is nice and quiet in
operation. When fully powered up there is a moderately loud hum from
the speakers which I think is due to the big electrolytic filter cap
and coupling caps. caps. The values of these a
big filter cap consists of 4 caps: 1x 30uF, and 3x 20uF, but rated at
525V.
coupling caps are 2x 0.05uF and 2x 1uF, all at 400V
(transformer also uses 2x 0.02uF at 1000V).
Any suggestions on a UK source for these?

Can you say why you have concluded that all these caps are responsible for
the hum, and thus conclude that all need replacing?

Have you tried using the unit with its inputs shorted? Or checking the
earthing arrangements?

If you have not already done so - it may be worth your while to remove the
caps and check their values before deciding which of them may need
replacing.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html