Hi All

Has anyone managed to use a push button digi-pot in front of an ECC83, if so
which one? I have looked at a few ICs but they have quite a low resistance,
47k - 100k. The DS1802 is looking favourite right now but any other info
would be appreciated.

cheers
Fox

"Fox" wrote in
:

Has anyone managed to use a push button digi-pot in front of an ECC83,
if so which one? I have looked at a few ICs but they have quite a low
resistance, 47k - 100k. The DS1802 is looking favourite right now but
any other info would be appreciated.

The biggest gottcha with the DS1802 is the Vcc maximum of 5.5 volts. This
severely restricts the swing voltage which can be applied to the pot
element (must lie in the [0..Vcc] range). A better choice might be the
DS1267 (I have used these extensively and really liked them) which give
you a [-7v..+7v] range but these dont have the handy button up/button
down options (you talk to them via a 3 wire interface, hence a little
microcontroller mungling is needed). I've heard good things about the
CS3310 from Crystal/Cirrus but never got around to trying it. Did try the
Xicor 95 series and that was an unmitigated disaster - they have an
onboard charge pump which redices audio to telephone quality. Nat Semi do
a few that look good on paper, and There is the great granny of them all,
the AD711x series, but they have gone the way of the dodo. AD have a
whole raft of new digipots out and the one I'm intrigued by is the :

http://www.analog.com/en/prod/0,,761...7376%2C00.html

Which (unusually for AD these days) is even available in DIP package.
It even comes in a 1meg variant, though the high resistance variants of
these things tend to be bandwidth restricted. Most of these parts are
linear, hence a bit of cunning needed.
You'll have to bit bang it to make it work.
M

Most of these parts are
linear, hence a bit of cunning needed.
You'll have to bit bang it to make it work.
M

You might consider using dual control pentode as
volume controls. See
http://pw2.netcom.com/~wa2ise/radios/elvctube.jpg
for ideas on how to do it. The digital chips could
create the variable DC voltage to feed to the 2nd
control grid. Or look at
http://pw2.netcom.com/~wa2ise/radios/6be6vol.html
for similar circuits using "TV" tubes.

The audio signal sees only tubes, so there would be no
issues of the chips munging the sound.

Hi Fox ,

Just connect one push button to a green light bulb and
another to a red one . This way the wife knows if she has
to turn up your high quality stepped attenuator or if she has
to turn it down ...... ;-))
You even might teach her some codes so she knows when
to bring beer or coffee ......

Ronald .


"Fox" schreef in bericht
...
Hi All

Has anyone managed to use a push button digi-pot in front of an ECC83, if
so
which one? I have looked at a few ICs but they have quite a low
resistance,
47k - 100k. The DS1802 is looking favourite right now but any other info
would be appreciated.

cheers
Fox

Hahahaha, yeah I can really see that happening....lol

anyway, thnx for the input guys

cheers
Fox
:-)


"Ronald" wrote in message
...
Hi Fox ,

Just connect one push button to a green light bulb and
another to a red one . This way the wife knows if she has
to turn up your high quality stepped attenuator or if she has
to turn it down ...... ;-))
You even might teach her some codes so she knows when
to bring beer or coffee ......

Ronald .


"Fox" schreef in bericht
...
Hi All

Has anyone managed to use a push button digi-pot in front of an ECC83,
if
so
which one? I have looked at a few ICs but they have quite a low
resistance,
47k - 100k. The DS1802 is looking favourite right now but any other info
would be appreciated.

cheers
Fox

Hi Fox ,

Don't tell the wife please .... !! She'll come after me ;-))

But I was only part kiddin' .
Why use a digital control in the first place ?
If you take a good (used ?) dual deck 24 steps turn switch
and solder some resistors to it , it should sound way better
than a digital controle . It might even beat the famous ALPS pots !!
There are formulas online for calculating the resistors .

Ronald .

"Fox" schreef in bericht
...
Hahahaha, yeah I can really see that happening....lol

anyway, thnx for the input guys

cheers
Fox
:-)


"Ronald" wrote in message
...
Hi Fox ,

Just connect one push button to a green light bulb and
another to a red one . This way the wife knows if she has
to turn up your high quality stepped attenuator or if she has
to turn it down ...... ;-))
You even might teach her some codes so she knows when
to bring beer or coffee ......

Ronald .


"Fox" schreef in bericht
...
Hi All

Has anyone managed to use a push button digi-pot in front of an ECC83,
if
so
which one? I have looked at a few ICs but they have quite a low
resistance,
47k - 100k. The DS1802 is looking favourite right now but any other
info
would be appreciated.

cheers
Fox

Hi Ronald

Well the reason for using the digi pots is because the case for my EL84
stereo project is actually a new Goodmans DVD player with all the gubbins
stripped out, which means there is some handy push button switchs that match
the case and look pretty neat. So my brain thought is was a good idea to use
them instead of sticking in a normal pot with a knob. There's a pic of the
case here :- http://www.mrspider.co.uk/stereoEL84.jpg , the dvd player was
cheap and the metal sturdy enuff to take the transformers, the dvd drawer
will be the final thing to be restored.
Thnx for the response, I did find the 24 turn switch idea very good in
other amps though.

cheers
Fox




"Ronald" wrote in message
...
Hi Fox ,

Don't tell the wife please .... !! She'll come after me ;-))

But I was only part kiddin' .
Why use a digital control in the first place ?
If you take a good (used ?) dual deck 24 steps turn switch
and solder some resistors to it , it should sound way better
than a digital controle . It might even beat the famous ALPS pots !!
There are formulas online for calculating the resistors .

Ronald .

Hi Fox ,

At least it looks good !!!! And I like the idea of using a cheap DVD
player for the chassis . It might be "THE" budget option buying a
2nd hand broken player .
Maybe you could use the push buttons as input selector and add a
ALPS fader type stereo pot in the "drawer" ??
The only real reason to keep the push buttons is if you want to
use the remote control I think . But an ALPS motor pot can be
an option there also I think .
For the input selector I would use some digital sh*t between the
switches and a hand full of relais' , but there might be a good
C-MOS switch chip for analog signals too (?) .

Best regards ,

Ronald .

"Fox" schreef in bericht
...
Hi Ronald

Well the reason for using the digi pots is because the case for my EL84
stereo project is actually a new Goodmans DVD player with all the gubbins
stripped out, which means there is some handy push button switchs that
match
the case and look pretty neat. So my brain thought is was a good idea to
use
them instead of sticking in a normal pot with a knob. There's a pic of the
case here :- http://www.mrspider.co.uk/stereoEL84.jpg , the dvd player was
cheap and the metal sturdy enuff to take the transformers, the dvd drawer
will be the final thing to be restored.
Thnx for the response, I did find the 24 turn switch idea very good in
other amps though.

cheers
Fox




"Ronald" wrote in message
...
Hi Fox ,

Don't tell the wife please .... !! She'll come after me ;-))

But I was only part kiddin' .
Why use a digital control in the first place ?
If you take a good (used ?) dual deck 24 steps turn switch
and solder some resistors to it , it should sound way better
than a digital controle . It might even beat the famous ALPS pots !!
There are formulas online for calculating the resistors .

Ronald .

Hi Ronald

At least it looks good !!!! And I like the idea of using a cheap DVD
player for the chassis . It might be "THE" budget option buying a
2nd hand broken player .

Yes, well my original idea was to have a chrome chassis but I'm useless at
metalwork, but I did see a fantastic chassis made in Germany however it
would cost 800UKP whereas the DVD player new was 39UKP. No competition
really, I just nipped out to the local HiFi store and spent the 39UKP, the
bonus being it was already fitted with a bank of phonos and power connector,
the scart socket can be replaced with the speaker outputs.

Maybe you could use the push buttons as input selector and add a
ALPS fader type stereo pot in the "drawer" ??
The only real reason to keep the push buttons is if you want to
use the remote control I think . But an ALPS motor pot can be
an option there also I think .
For the input selector I would use some digital sh*t between the
switches and a hand full of relais' , but there might be a good
C-MOS switch chip for analog signals too (?) .

Indeed that was my backup plan if the digipots dont work well, the slot
is 13cm long, just right for 2 sliders! I am tempted to disregard the
switching as the amp will only have 2 stereo inputs, dvd/cd and satellite.
Just simple mixing with the lowering of one of the inputs to zero might
suffice, that's gonna be a 'suck it and see' idea. If I need the switching
I'll definitely go for the CMOS approach as I will already have built the +-
5V by then, might as well use it.
I'll let ya know how it turns out, should be finished in 2 weeks I reckon
(heard that one before somewhere...lol).


Cheers
Fox