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Building a Tube Amp

J

Jon Slaughter

Jan 1, 1970
0
I've been wanting to build my own tube amp for a while now and I think I'm
going to go ahead and order the parts.

Anyone know a good source of parts(transformers, tubes, tube sockets,
etc...) and maybe have any tips? I have a few old tube books and of course
mostly they are similar to transistor amps. But I, of course want a decent
sound also.

I know one can buy "kits" but these tend to be either over priced and/or low
quality.
 
J

Jan Panteltje

Jan 1, 1970
0
I've been wanting to build my own tube amp for a while now and I think I'm
going to go ahead and order the parts.

Anyone know a good source of parts(transformers, tubes, tube sockets,
etc...) and maybe have any tips? I have a few old tube books and of course
mostly they are similar to transistor amps. But I, of course want a decent
sound also.

I know one can buy "kits" but these tend to be either over priced and/or low
quality.

2 x 807 zero bias drive?
 
J

Jon Slaughter

Jan 1, 1970
0
Jan Panteltje said:
On a sunny day (Tue, 14 Oct 2008 07:07:43 -0500) it happened "Jon
Slaughter"


2 x 807 zero bias drive?

It's going to be class A but I'm not sure exactly what tubes I'm going to
use. Probably try to make it switchable for different power settings.
Basically the "stock" guitar amp tubes are the 6L6, 12AX7, EL34, EL84 and a
few variants.

http://www.vacuumtube.com/guitartubes.htm

Although I'd like potentially to "branch" out into other non-standard types
I also don't want to pay an arm and a leg for crappy tubes.

The main thing right now is to find a good transformer... looks like I'll
end up spending more to build an amp than just buy a good one ;/ (which is a
real shame since labor isn't even factored in ;/)
 
E

Eeyore

Jan 1, 1970
0
Jon said:
I've been wanting to build my own tube amp for a while now and I think I'm
going to go ahead and order the parts.

Anyone know a good source of parts(transformers, tubes, tube sockets,
etc...) and maybe have any tips? I have a few old tube books and of course
mostly they are similar to transistor amps.

Not even remotely.

But I, of course want a decent sound also.

The best output transformers are in Europe IMHO. Lundahl and Sowter for example
but hardly cheap. SS amps don't need output transformers.

But why do you want to add tube distortion to the sound ?

May I suggest you Google 'gainclone' for something half decent ?

Graham
 
J

Jan Panteltje

Jan 1, 1970
0
It's going to be class A but I'm not sure exactly what tubes I'm going to
use. Probably try to make it switchable for different power settings.
Basically the "stock" guitar amp tubes are the 6L6, 12AX7, EL34, EL84 and a
few variants.


807very popular here, 2 make for 100W.
'Zero bias' drive, here an example:
http://www.triodeel.com/mi12246.gif


Near class A:
http://www.montagar.com/~PATJ/mi12188a.htm


You may want to read this:
http://www.webace.com.au/~electron/tubes/screens.htm

http://www.vacuumtube.com/guitartubes.htm

Although I'd like potentially to "branch" out into other non-standard types
I also don't want to pay an arm and a leg for crappy tubes.

EL84 is rather low power, I used those in a guitar amp once, 4 IIRC.

The main thing right now is to find a good transformer... looks like I'll
end up spending more to build an amp than just buy a good one ;/ (which is a
real shame since labor isn't even factored in ;/)

That is why I spend say about 100$ on a Chinese 2 x 100W RMS transistor amp.
Cheaper, better, and faster too, as it came working.

Just forget about tubes :)
And the voltages can byte you too.
 
J

Jon Slaughter

Jan 1, 1970
0
Eeyore said:
Not even remotely.



The best output transformers are in Europe IMHO. Lundahl and Sowter for
example
but hardly cheap. SS amps don't need output transformers.

But why do you want to add tube distortion to the sound ?

May I suggest you Google 'gainclone' for something half decent ?

FYI, Tube's break up differently than SS. Tubes have even order harmonic
distortion which is much more pleasent than odd order. This has to do with
how they clip... hence tubes are prefered over SS any time distortion is
involved. (and with the need for an overdriven sound for guitar it is
necessary)
 
J

Jan Panteltje

Jan 1, 1970
0
FYI, Tube's break up differently than SS. Tubes have even order harmonic
distortion which is much more pleasent than odd order. This has to do with
how they clip... hence tubes are prefered over SS any time distortion is
involved. (and with the need for an overdriven sound for guitar it is
necessary)

You are aware, I hope, that you can make any waveform at low level,
and then amplify it by a normal transistor amp (without it clipping)?
Seems like you have been bitten by a tubophile !
 
J

Jon Slaughter

Jan 1, 1970
0
Jan Panteltje said:
On a sunny day (Tue, 14 Oct 2008 08:59:13 -0500) it happened "Jon
Slaughter"


You are aware, I hope, that you can make any waveform at low level,
and then amplify it by a normal transistor amp (without it clipping)?
Seems like you have been bitten by a tubophile !

Huh?

You do realize that overdriven guitar amps purposely distort the signal?

I guess you guys don't know much about guitar amps?
 
J

Jon Slaughter

Jan 1, 1970
0
Jan Panteltje said:
On a sunny day (Tue, 14 Oct 2008 08:23:00 -0500) it happened "Jon
Slaughter"



807very popular here, 2 make for 100W.
'Zero bias' drive, here an example:
http://www.triodeel.com/mi12246.gif


Near class A:
http://www.montagar.com/~PATJ/mi12188a.htm


You may want to read this:
http://www.webace.com.au/~electron/tubes/screens.htm



EL84 is rather low power, I used those in a guitar amp once, 4 IIRC.



That is why I spend say about 100$ on a Chinese 2 x 100W RMS transistor
amp.
Cheaper, better, and faster too, as it came working.

Just forget about tubes :)
And the voltages can byte you too.

I guess I wasn't clear(actually I don't see that I mentioned it). The amp is
specifically for guitar and not hi-fi.
 
G

GregS

Jan 1, 1970
0
You are aware, I hope, that you can make any waveform at low level,
and then amplify it by a normal transistor amp (without it clipping)?
Seems like you have been bitten by a tubophile !

Seems like you can make a lot of money marketing your device.

Seems like overdriving the power output stage might not
have the same irregularities as a low level stage.

Guitars can be played with any kind of amp and don't necessarily
need to be driven into distortion. Thats determined by the artist.
The type of speaker distortion is also part of the power output
stage.


greg
 
Huh?

You do realize that overdriven guitar amps purposely distort the signal?

I guess you guys don't know much about guitar amps?

That doesn't follow. What we do know is that it is lot cheaper to
distort a signal with semiconductors and subsequently amplify it with
semiconductors than it is to amplify and distort it with valves.
Semiconductors have the additional advantage that you can have a lot
more control over the nature of the distortion you introduce and the
signal level where it becomes perceptible, if you happen to know what
you are doing.

Since you seem to be planning on building a valve amplifier for your
guitar, you presumably don't have a clear idea of what you are doing.
 
J

Jan Panteltje

Jan 1, 1970
0
Seems like you can make a lot of money marketing your device.

Nah, all been done likely.

Seems like overdriving the power output stage might not
have the same irregularities as a low level stage.

Possible, but that is not what I suggested.

Guitars can be played with any kind of amp and don't necessarily
need to be driven into distortion. Thats determined by the artist.
The type of speaker distortion is also part of the power output
stage.

Sure, google 'guitar distortion box' without the quotes.
Only 212000 hits.

:)

Just typed:
# killall -KILL tubophiles
# tubophiles: no process killed
mm
Oh well.
 
J

Jan Panteltje

Jan 1, 1970
0
On a sunny day (Tue, 14 Oct 2008 10:06:12 -0500) it happened "Jon Slaughter"
<[email protected]>:

START:
Huh?

You do realize that overdriven guitar amps purposely distort the signal?

I guess you guys don't know much about guitar amps?

GOTO START
 
J

Jan Panteltje

Jan 1, 1970
0
I guess I wasn't clear(actually I don't see that I mentioned it). The amp is
specifically for guitar and not hi-fi.

For 'amplification' one would like as little distortion as possible.
For wave shaping, it is better done at lower power levels.

If you can specify the waveform (distortion type) you want,
then you can can make that either digitally or analog at a low
level, and then use a HiFi power amp.
At least you would have a decent amp :)
 
J

Jon Slaughter

Jan 1, 1970
0
Jan Panteltje said:
On a sunny day (Tue, 14 Oct 2008 10:07:57 -0500) it happened "Jon
Slaughter"


For 'amplification' one would like as little distortion as possible.
For wave shaping, it is better done at lower power levels.

If you can specify the waveform (distortion type) you want,
then you can can make that either digitally or analog at a low
level, and then use a HiFi power amp.
At least you would have a decent amp :)

You can't... the components in a tube amp react completely different than
digital algorithms. Analog solid state tends to end up sounding very
harsh(because of the way they clip as I mentioned).

If you don't believe me go to your local music store and ask one of the guys
to show you how a real tube amp sounds. Compare it to a solid state amp and
then to a modeling amp. The tube amp wins in sound quality.

Supposedly there are many factors in tube amps that make them sound better
such as the power transformer "sagging", the tubes themselfs, etc... I do
not know how much is true but what I do know is that tube amps sound much
better than solid state... although some of the newer modeling amps do sound
decent but still are not "reactive" to the playing. (they are not dynamic or
"organic" as it's still just a simple algorithm that reacts the same way
every time)


(Remember, I'm specifically talking about distortion here... but even then
many people claim hi-fi tube amps are the best. (and I've seen research that
claims they are))
 
J

Jon Slaughter

Jan 1, 1970
0
John Larkin said:
Why not build a low-level distortion box and pipe it into a cheap
commercial stereo amp? That would save a ton of money and give you a
lot of versatility to tune the sound. You don't get a lot of choice or
tunability from a pile of tubes and transformers.

John

They have these but generally the power amp distortion(along with speaker
distortion) is also needed. A simple preamp tube driver with solid state
doesn't sound all that great.

You would be supprised what they do with tube guitar amps though.

check out

http://www.mesaboogie.com/Product_Info/Rectifier_Series/roadking/roadking.htm

and look at the back for all the switching possibilities.
 
J

Jan Panteltje

Jan 1, 1970
0
That argument could easily be applied to building violins out of
plastic, or just using sampled violin sounds in a synthesizer instead of
a string orchestra.


Maybe you have not noticed, but whole orchestras come out of the paper cone of your loudspeaker,
and the plastic membranes of your headphone.
Yet somehow, when I go to the symphony it's all flesh-and-blood people
playing wooden instruments.

Probably amplified by ....
Circa 1985 you couldn't build a solid state 'distorter' that would
satisfactorily replicate the sound of a tube amp.

Ah come on!!!!
You may be able to now, but it takes a tremendous amount of work to
design. There's a lot of dynamic nonlinearities at work, in the tubes,
in the transformers and in the speakers. And it's not limited to the
audio path -- even the power supply sag modifies the sound ("adds
crunch", per the folks who study this).

And that would be difficult?
Hell the only limiting factor doing it all digitally was the introduced delay.
Today, with GHz FPGAs and very fast DSPs, I think there is hardly any problem
doing simple things like that.

So yea, for reproduction the "vacuum tube sound" probably makes no
sense. But given that the distortion of the amplifier is an integral
part of rock & roll guitar, I think it'll be a while before vacuum tube
amps can really be replaced.

I like that article that Guy Macon pointed to:
http://www.trueaudio.com/at_eetjlm.htm

That whole tube stuff is marketing, just like oxygen free cables.
Some will prefer to ride horses as those feel so 'soft' versus driving
in a car I guess.
 
J

Jan Panteltje

Jan 1, 1970
0
You can't... the components in a tube amp react completely different than
digital algorithms. Analog solid state tends to end up sounding very
harsh(because of the way they clip as I mentioned).

If you don't believe me go to your local music store and ask one of the guys
to show you how a real tube amp sounds. Compare it to a solid state amp and
then to a modeling amp. The tube amp wins in sound quality.

Supposedly there are many factors in tube amps that make them sound better
such as the power transformer "sagging", the tubes themselfs, etc... I do
not know how much is true but what I do know is that tube amps sound much
better than solid state... although some of the newer modeling amps do sound
decent but still are not "reactive" to the playing. (they are not dynamic or
"organic" as it's still just a simple algorithm that reacts the same way
every time)


(Remember, I'm specifically talking about distortion here... but even then
many people claim hi-fi tube amps are the best. (and I've seen research that
claims they are))

Well, dear Jon, I have build several tube amps, how many did you build?
But really I would not recommend tube amps, unless you like to look
at red hot glowing anodes, those look nice, and show you that it is time to
turn the volume down.
And, if you have limited experience with electronics, the voltages in tube amps
can kill, so better make something that works on 2 x 40 V with transistors.
 
J

Jan Panteltje

Jan 1, 1970
0
If you would be so kind as to point me to a wholly synthesized rendition
of Beethoven's 5th that is entirely synthesized, and is generally
recognised as sounding better than an orchestral version generated by
real people?

You are confusing 2 things, first there is the input from the *player*,
then there is the sound of the *instrument*.
Naturally both are tightly coupled, but I am pretty sure (well assumption),
that if Stradivarius played some run of the mill made in Mechico violin,
he could still keep an audience in awe.



You have one that was built in 1985 and enjoyed any kind of acceptance
at all by serious musicians?

That is a straw man.
The issue is 'can we make a tube sound at low level'.
Well any diode clipper does that.
Now you can add other stuff, like 'sagging supply', quite easily, by doing a peak detection
and lowering the diode biases, etc etc.
Asymmetric? Can be done too, the 'Joerg way', couple of discretes,
some JFETS, what not.
There is no problem there.
The problem is in their idiotic specs, 'soft', colourful', 'sexy', 'fuzzier',
'warmth', 'alive', 'organic' hey, what does it mean?
Does it mean the same thing to person A as to person B?
So you first have to come up with some real tests, scope it,
see what is different, and recreate that with some hardware, software,
lookup tables if you must (AD EPROM DA for curve, now there is hardly latency),
etc.
Formulate the exact problem, and you have the solution.

Not so. Yes, the technology enables it, but that leaves the limiting
factor of our understanding of the mechanisms at work modifying the
sound, and the labor involved in replicating them in DSP.

Sure, right.

I think it can be done (I think it _has_ been done), but it'd be a hell
of a lot of work for a very talented team. If you think you can do it
on your own with a few lines of Verilog, then get cracking -- there's a
river of money to be had if you make it work cheaply.

No way, I do not like to sell snake oil, and I do not want to stimulate anybody
to believe in snake oil.
And I would have to advertise in their snake oil language to sell it.
Simple as that.

So if you're making a bazillion (and you think you can market it to
guitarists) then you can plan on amortizing all that engineering expense
over a bunch of units, and it makes sense. If you're building one --
get some tubes, buddy.

Personally I think very few real guitarist give a dime.
They can play, and use the instrument to express themselves.
A lot of others will just go for some sort of special sound, well it is not that
what makes music, Hendrix burned his guitar on stage IIRC, good thing too.

(am I gone hear about this LOL).

Yup. And my 2000 Ford Escort (and anything else with a motor) will
climb right past those horses going up that 45 degree slope with those
8" rocks cluttering the 18" wide trail.

Oh, did not know that.
To each his own ;-)
 
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