Keith G pibbled:
"Wally" wrote in message
...
Keith G wrote:

And rightly so - see this pic of the impending project......

http://www.apah69.dsl.pipex.com/keith_g/show/2a3a.jpg
....wodger reckon - a bit *too* far the 'other way'....???

I'd put covers on the rest of the transformers. Apart from that, it looks
fine to me. (Better finish than my own DIY jobbie...)



Oops, better clear up any confusion - that ain't my work, that's a pic of
the amp I intend to build as a 'trial triode'!!



DIY transformers? Optimistic.

Hint: Connect the O/P valves to the 240VAC side, the 12-0-12 goes to the
speakers


--
Despite appearances, it is still legal to put sugar on cornflakes.

"Triffid" wrote
Hint: Connect the O/P valves to the 240VAC side, the 12-0-12 goes to the
speakers

Hey, I've done that, when I was a teenager fiddling around
trying to make a valve amp!

The anodes always got a bit too hot though, by the time
I got a decent power out of it.

Like, glowing orange sometimes!


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk

In article ,
Jem Raid wrote:
I would agree that folded horns are not new but then neither are boxes,
folded horns because of the design sound better than boxes. Clear and
open as opposed to muffled and sad when you listen to them side by side
:-)

We'll have to differ there. The *main* problem with any horn design is
colouration. And I've owned horn speakers - Tannoy Autographs.

--
*Marriage changes passion - suddenly you're in bed with a relative*

Dave Plowman London SW 12
RIP Acorn

"tony sayer" wrote

....wodger reckon - a bit *too* far the 'other way'....???

:-)




I reckon your missus should be grateful that you're doing summatt useful
in your shed, and not out boozing or womanising;-)


I agree entirely!



QUAD's are keepin well BTW


Good oh!

;-)

"Wally" wrote in message
...
Keith G wrote:

http://www.apah69.dsl.pipex.com/keith_g/show/2a3a.jpg

Stereo?

Yep.

What's the o/p valve?

2A3

What are the little ones?

Don't know yet.

Is the bottom-right
coil a PSU choke?

Probably.

What rectifier?

Don't know yet.


Where can I get a look at the cct diagram? :-)

I haven't got it myself yet - it's being morphed from a separate pre and a
mono circuit which, I understand, will be derived from (or as) one of the
circuits on this page:

http://www.studiomaudio.com/loftinwhite.html


(Figs 2 - 9 only, I suspect.) If you are interested, I've posted two more
pix of this amp:


http://www.apah69.dsl.pipex.com/keith_g/show/2a3b.jpg

http://www.apah69.dsl.pipex.com/keith_g/show/2a3b.jpg


If you want to take it further, contact Phil at Bluebell Audio
http://www.bluebellaudio.com/ who will supplying the circuit diagrams and
the whole shooting match for the build (a virtual 'parts kit' at an
*extremely* attractive price) and buy some stuff from him! - He's not
expensive and we need to keep these guys going in the UK!

"Keith G" wrote in message
...

"Wally" wrote in message
...
Keith G wrote:

http://www.apah69.dsl.pipex.com/keith_g/show/2a3a.jpg

Stereo?

Yep.

What's the o/p valve?

2A3

What are the little ones?

Don't know yet.

Is the bottom-right
coil a PSU choke?

Probably.

What rectifier?

Don't know yet.


Where can I get a look at the cct diagram? :-)

I haven't got it myself yet - it's being morphed from a separate pre and a
mono circuit which, I understand, will be derived from (or as) one of the
circuits on this page:

http://www.studiomaudio.com/loftinwhite.html


(Figs 2 - 9 only, I suspect.) If you are interested, I've posted two more
pix of this amp:


http://www.apah69.dsl.pipex.com/keith_g/show/2a3b.jpg

http://www.apah69.dsl.pipex.com/keith_g/show/2a3b.jpg



Bugger!

Second link should be:

http://www.apah69.dsl.pipex.com/keith_g/show/2a3c.jpg

Keith G wrote:

Oops, better clear up any confusion - that ain't my work, that's a
pic of the amp I intend to build as a 'trial triode'!!

Yup, I'd gathered that an impending project wouldn't be complete yet...


I need to sort this triode thing out for myself - half the world says
they're ****e, the other half says they're the very best sound
(holographic?) you can get (SE) ...

I can't help feeling that the speakers and room would have more to do with a
sound having a 'holographic' quality than the particular type of valve in an
amplifier. So far as I can see, a single-ended triode o/p would be prone to
distortion if it's used to anything like its rated power. I remember
fiddling with load and bias resistors in a pin-board ECC83 preamp I was
messing about with, and was able to dial in any amount of 2nd harmonic
distortion for a given input level.


... and I sure as hell can't/wouldn't
spend the stoopid money for an exotic 'ready-made' number..!!

Nor I. I just don't need a fancy box *that* much. I've been thinking about
home-brew front panels. Apparently, in the model steam engine scene, people
are into making little brass nameplates for their engines.They do it by
applying a resist to the brass and then etch out the design using a
chemical - like making a PCB. The pattern on the resist is made using a
computer and printer, so the layout is as good as one's PC skills will allow
for. After etching, the cavity is filled with paint, leaving the unetched
high spots as brass. It strikes me that that could be a good way to get
clean, accurate and long lasting legends on a front panel for an amp.


Assuming I don't short myself out, I'll be posting pix and and a
description of the build (f*ck-up?) when I'm done!

Take some shots as it progresses - photo of a pile of bits, case with holes,
some of the bits in place, etc.


(Explanation: There's a shop over in the town that sells gerbils with
more 'electronics knowledge' than I have.....!! :-)

If you can solder wire to tags and run it fairly neatly, you should get on
okay if there are good instructions with the kit.


--
Wally
www.forthsailing.com
www.wally.myby.co.uk

Keith G wrote:

What's the o/p valve?

2A3

What speakers are you planning to drive with it?


(Figs 2 - 9 only, I suspect.) If you are interested, I've posted two
more pix of this amp:

Nice piece of kit. I like the earth buss next to the tagstrip.


If you want to take it further, contact Phil at Bluebell Audio
http://www.bluebellaudio.com/ who will supplying the circuit diagrams
and the whole shooting match for the build (a virtual 'parts kit' at
an *extremely* attractive price) and buy some stuff from him! - He's
not expensive and we need to keep these guys going in the UK!

Not planning to build one, just taking a wee interest. My hifi DIY stuff is
in a different direction at the moment - I'm currently musing over how to
make a prototype of the tapered tubular midrange speaker cabinet.


--
Wally
www.forthsailing.com
www.wally.myby.co.uk

"Jim Lesurf" wrote in message
...
In article , Jem Raid
wrote:


Your coments bear out my experience in engineering, the people who do
know how to do things well are all over 50 and most of them want to or
do get out of it, creating a skill shortage despite the shrinkage of
manufacturing.

I have mixed feelings about the above. :-)

I officially start my early retirement tomorrow. Plan to be 'active' in my
retirement, though... ;-

Slainte,

Jim

Congratulations Jim - you've made it!

Rob

In article ,
Wally wrote:
Nor I. I just don't need a fancy box *that* much. I've been thinking
about home-brew front panels. Apparently, in the model steam engine
scene, people are into making little brass nameplates for their
engines.They do it by applying a resist to the brass and then etch out
the design using a chemical - like making a PCB. The pattern on the
resist is made using a computer and printer, so the layout is as good as
one's PC skills will allow for. After etching, the cavity is filled with
paint, leaving the unetched high spots as brass. It strikes me that that
could be a good way to get clean, accurate and long lasting legends on a
front panel for an amp.

RS Components do a coated anodised aluminium sheet in a couple of
thicknesses - 0.5 mm and IIRC 1.5 mm, so suitable either as a main panel
or cover.

1) You do a transparency in the same way as you would for a PCB, then
contact print it onto the sheet using UV light.

2) Then wash the sheet and dry. It's pretty robust by now.

3) Next, you coat the 'etched' parts with the supplied dye - red blue
green yellow or black, and wipe off the excess. It's possible to use
different colours on the same panel with care.

4) You then strip off the emulsion with the supplied stripper

5) Finally, you simmer in boiling water for 40 minutes.

The final result is as durable as anodised aluminium - ie rather better
than good quality screen printing.

The kit is expensive - over 100 quid - but includes two each 320 x 250 mm
panels of both thicknesses, double sided sticky backed paper for fixing,
and all parts can be bought separately.

The RS part number is 568-073 and you can download the data sheet/full
instructions from their site.

IMHO, it's a *very* cost effective way of getting a pro finish to your
front panel - as anyone who has had pro engraving done will agree. ;-)

http://rswww.com

--
*I almost had a psychic girlfriend but she left me before we met *

Dave Plowman London SW 12
RIP Acorn