Hello there!
Sorry i haven't made any introduction yet, but i'm a bit anxious about this first post.
What simple circuits are recommended for the ECC88/6DJ8, as i have around 4 of them and 3 PCC88?
I have very little experience with tubes and would like to avoid complicated circuits, as i don't also have access to real output trannies.
Many thanks to all, hoping to be a regular poster too.
Cheers!
Sorry i haven't made any introduction yet, but i'm a bit anxious about this first post.
What simple circuits are recommended for the ECC88/6DJ8, as i have around 4 of them and 3 PCC88?
I have very little experience with tubes and would like to avoid complicated circuits, as i don't also have access to real output trannies.
Many thanks to all, hoping to be a regular poster too.
Cheers!
Heck, you can use them for output too. Join me in owning a MP (massively parallel) amplifier. 
Although with only four, you'd be better off using them for gain, line or driver stages. A lot of neat things can be done with these types as they can pull pretty good current, for a recieving tube.
Tim
Although with only four, you'd be better off using them for gain, line or driver stages. A lot of neat things can be done with these types as they can pull pretty good current, for a recieving tube.
Tim
4xECC88 could make a nice headphone amplifier for 300 Ohms or higher headphones. I posted a schematic recently..
http://www.diyaudio.com/forums/showthread.php?threadid=49349
Jakob E.
http://www.diyaudio.com/forums/showthread.php?threadid=49349
Jakob E.
This immediately came to mind
The original circuit (Aikido):
http://www.tubecad.com/2004/blog0011.htm
Aikido variations :
http://www.tubecad.com/2004/blog0013.htm
More Aikido :
http://www.tubecad.com/2004/blog0016.htm#MoreAikido
Aikido Revisited :
http://www.tubecad.com/2005/January/blog0030.htm
And finally where one person sends his distortion results in (With all ECC88)
http://www.tubecad.com/2005/January/blog0032.htm
Happy reading!
Don't worry about the "complexity" if you decide to go this way...you'll get plenty support from here!
ps..I'm building on myself just for fun...and to see how it sounds..
Cheers,
Bas
I'm making a super simple PL504 amp for my PC speakers, after a circuit by Mr. Burkhard Kainka, just some 4 resistors per channel, but i have no will to complete it, i'm just so "soft".
But the aikido looks neat!
I also have a 6X4 rectifier, maybe i'll give it some use on the PS.
Thank you guys!
But the aikido looks neat!
I also have a 6X4 rectifier, maybe i'll give it some use on the PS.
Thank you guys!
regarding the Aikido
Bas, could you detail a little more about the Aikido?
It's seems to me that only the cathode resistors need to be changed/tweaked to suit a certain tube family, with the potencial divider resistors needing only to be equal, with a wide variation in their value.
Am I right?
cheers!
Bas, could you detail a little more about the Aikido?
It's seems to me that only the cathode resistors need to be changed/tweaked to suit a certain tube family, with the potencial divider resistors needing only to be equal, with a wide variation in their value.
Am I right?
cheers!
Hi tzere...
They're were also in UHF tv tuners..........a lovely little hi slope tube, I use 'em in parallelled cathode follower config with 3:1 step down parafeed tranny to 600 ohm /o/p's ...With anode tied to B+ supply it will need close decoupling caps on the anode sock pins 1,6 otherwise it can oscillate with langky wiring....also use 10K grid stoppers.
rich
PCC and ECC88 are electrical equivalents except for the heater supply, but even this is only slightly different - on the ECC variant it's 6.3V, on the PCC it's 7V. If an 8V or higher heater supply is available, a suitable series resistor in the heater supply will aow complete interchangeability of the PCC88 and the ECC88.
I would not be to worried about running PCC88 off 6.3V either. 10% is perfectly normal variation for series heated tubes, and the heater compensates for voltage changes quite well. I've just tested this on a bench power supply - the heater power, and therefore temperature, is only a few % off at 6.3V for an Ei PCC88 I have here. It's dead on 7V at 300mA, and 321mA at 6.3V so 2.1W in the first case and 2.02W in the second, that would be a ~~4% difference - negligible. Still, if you want to be anal and have extra voltage, you can insert a resistor and have it practically dead on no matter which variant you plug in there.
As long as you are not demanding rated cathode current, running small signal tubes on reduced heater voltage makes them more linear. See http://www2.famille.ne.jp/~teddy/datalib/heater.htm to see some plate curves of a few triodes. (Page is in Japanese, but the curves are quite readable). He has some 12AX7s and 12AU7s and equivalents on reduced heater voltages, and it looks like 10V for 12.6V looks to be a linear sweet spot. That's about the same as running a 7V tube on 5.5V or in the case of the 7V tube on 6.3V that's like running the 12AX7 on 11.34V, still more linear than at rated heater voltage. So the PCC88 will work quite well on 6.3V
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