Tube amplifier
 

Hi,

I would like to build my own tube amplifier. Where can I find
information and circuit diagrams on the net?

Thanks,

Vasilis

Tube amplifier
 

Hello Vasilis.
I wish you much joy and fun in building a tube amplifier - welcome! I think I
would start with Morgan Jones book Valve Amplifiers ed. 3. It's worth reading
it cover to cover just to start with (including essential safety instructions
for all valve equipment) then, if you have Excel, it's worth taking out all the
equations and copying them into Excel into a spreadsheet kept for that purpose.
You need all the ohms law calculations in all versions, and also output valve
calculations/ transformer, resistors in combinations, frequency turnover of
cap/resistor combinations. then you want all the calculations for an individual
stage - gain, current, voltage etc. You should be using these calculations all
the time. You may already have electronics knowledge - I don't know, in which
case you will know all this. When you start building, Morgan's book will help
with questions that come up - the second volume of ed. 3 also deals with
construction.
You should subscribe to: www.diyaudio.com and www.audioasylum.com
In these two forums you will get expert help which you won't get on this
newsgroup, a much better place to discuss your build, and in general a much
better class of people - helpful and courteous towards valve users. Both sites
have excellent and comprehensive search facilities, and you can search for
individual valve types (mainly on the asylum in the 'tubes' section) or
topologies and technical stuff (mainly in the tubesDIY section) or SET (on the
SET section). You can also do a seacrh of all forums. If you want schematics,
enter 'schematic' (more likely to get results than 'circuit diagram') and your
parameters, e.g. EL34
The next thing to do is go to http://tdsl.duncanamps.com/tubesearch.php. this
is the Duncanamps site - invaluable for tube data. You should download two
things from there - the tube data TDSL and the power supply calculator PSU
designer 2. also keep note of http://hereford.ampr.org/cgi-bin/tube?tube=el822
which is another great site for tube data.
As for what to build, I'd be tempted to try Allen Wright's stuff.
http://www.vacuumstate.com/ is his site. If you're in the UK you can make a
cheap version of his amp using the Maplins power and output transformers parts
DM54 and DM53. this will give you good quality and with a modern circuit like
Allens you will get better sound than older circuits such as the World Audio
Design kits. For valves I'd use Edicron - reliable, well matched and cheap. Get
valves direct from them - Troy is very helpful. www.edicron.com They will give
you good EH6922 for Allen's circuit - this is an excellent front end. I'd be
tempted to go for some Sovtek 2a3 output valves instead of the EL34s in the
circuit - you just need some 2.5v transformers. You can get those from
http://www.vvttransformers.co.uk/ . For the rest of the parts I'd recommend CPC
(subset of Farnell). they have a big thick catalogue you should get, and they
usually have nice offers and discounts for new members. www.cpc.co.uk.
All this should get you started! Good luck and come back with any questions.
You'll also find a few useful valve people on this newsgroups like Nick Gorham,
who I'm sure will be pleased to help out. Patrick Turner will give you full,
informative advice on almost anything and is a real friend in need. Top bloke.
andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Tube amplifier
 

On Thu, 09 Dec 2004 22:36:11 -0800, wrote:

Hi,

I would like to build my own tube amplifier. Where can I find information
and circuit diagrams on the net?


I think Andy has answered you very well, but just consider what sort of
amplifier do you *need*? (We all know "what would be nice", but most
people run into cost limitations at some point!)

First, where do you intend to use it, and what for? The demands of an
instrumentation amp are quite a bit different to those of a hi-fi amp.

An amp intended to drive a couple of small speakers from a CD player in
your bedroom can be smaller and simpler than one for your main hi-fi in
the lounge.

Do you need headphones? Are they, perhaps, even more important than the
speakers?

Do you already have sensitive loudspeakers, or do you think you will need
to buy some more - or build a more powerful amp to drive existing
insensitive ones?

Do you need tone controls? If so, how do you want them to work?

Do you need input from a record deck, or is CD input only ok?

You really need to write down *exactly* what you need before you start
looking round. It could be that no-one has designed *exactly* what you
want yet! :-)

It will probably be worth while building a small amp just as an
experimentation platform. That way you can experiment with different
components and circuits without having to make the thing too pretty! ;-)
It also means that you can gain some experience with valve amp techniques
before plunging into your "ultimate" project...

--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info
Web: http://projectedsound.tk

Tube amplifier
 

wrote in message
oups.com
Hi,

I would like to build my own tube amplifier. Where can I find
information and circuit diagrams on the net?

Try searching google for "tube amplifier schematics".

I tried this myself and found this one:

http://members.aol.com/aria3/output.htm

I then found this note:

http://members.aol.com/aria3/reliable2.htm

"The biggest problem with the amps is poor current haring between the output
triodes. All 4 need to be matched closely to prevent failures. Initial
matching on the bench ensures initial reliability."

A hearty DOOOH! to that!

Tube amplifier
 

"Arny Krueger" wrote
"The biggest problem with the amps is poor current haring between the output triodes. All 4 need to be matched closely to
prevent failures. Initial matching on the bench ensures initial reliability."

A hearty DOOOH! to that!

**** me. It must be a **** design then.

Do you design a transistor circuit making assuptions about h_FE?


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

Tube amplifier
 

"Fleetie" wrote in message
...
"Arny Krueger" wrote
"The biggest problem with the amps is poor current haring between the
output triodes. All 4 need to be matched closely to prevent failures.
Initial matching on the bench ensures initial reliability."

A hearty DOOOH! to that!

**** me. It must be a **** design then.

Do you design a transistor circuit making assuptions about h_FE?

**Some do. Fortunately, BJTs offer very long term hFE stability, once
chosen. Valves, OTOH, vary all over the place, with time.


--
Trevor Wilson
www.rageaudio.com.au

Tube amplifier
 

In article , Fleetie
wrote:
"Arny Krueger" wrote
"The biggest problem with the amps is poor current haring between the
output triodes. All 4 need to be matched closely to prevent failures.
Initial matching on the bench ensures initial reliability."

A hearty DOOOH! to that!

**** me. It must be a **** design then.

Do you design a transistor circuit making assuptions about h_FE?

Yes. I assume it will vary over a range bigger than written in the
databook, and slug the value accordingly. :-)

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

Tube amplifier
 

"Fleetie" wrote in message

"Arny Krueger" wrote
"The biggest problem with the amps is poor current haring between
the output triodes. All 4 need to be matched closely to prevent
failures. Initial matching on the bench ensures initial
reliability." A hearty DOOOH! to that!

**** me. It must be a **** design then.

Do you design a transistor circuit making assuptions about h_FE?

Yeah, I presume that h_FE will be all over the map. While Trevor is right
about a given device sample having stable characteristics, that's only true
if the device is operating under tightly-controlled circumstances that are
unrealistic in the real world.

IOW h_FE varies with temperature, current, applied voltage...

And it varies from device to device.