Tube/Valve buffer with ECC88

[formula 22]

Hi all!
I need schematics or project for Tube/Valve buffer with ECC88 or PCC88 that will be power supply Ucc=+/-25V.
Thanks and cheers!

 

[revintage]

+/-25V will give a sh-tty performance. Add a doubler on the positive side as it might work acceptable with +50V. Just check the Ua/Ia curves.

If you want a tube that works OK at low voltage you should go for 6N30.

Understand from your doublethread that this is for a Gainclone project.

And as someone else said, use Google. There are lots of, more or less, doubtful projects out there.

 

[Audiofanatic]

Use the Tube part !

I hope it helps you a bit in the right direction !
Not my cup of tea but it works


Audiofanatic

 

[Eli Duttman]

Hi all!
I need schematics or project for Tube/Valve buffer with ECC88 or PCC88 that will be power supply Ucc=+/-25V.
Thanks and cheers!

For use with a 25⁺ - 0 - 25^- bipolar PSU, the tube to use is the 6GM8/ECC86. Constant current sink (CCS) load, at 2 mA. each, the pair of cathode followers and you're pretty much done.

 

[formula 22]

I hope it helps you a bit in the right direction !
Not my cup of tea but it works


Audiofanatic

Hello Audiofanatic!

Very intersting simple schematic!

Ist it your project if you have crated this project interst me how they behave steam harmonics in the amplifier?

Give please show graphs.

You'll be very greatefu!!!

 

[formula 22]

Hybryd amplifier with PCC88 and LM1875

Hello!
It has 2 pieces PCC88 and 2 pieces LM1875 and 1 pieces toroidal transformer with the 230Vac/2x18Vac/100VA . From all this i want to i create a hybrid audio amplifier, so please give suggestions on how all of this to close the stereo amplifier.
Thank you for your cooperation !

P.S.
Is it can be replacet 6922 with PCC88 or ECC88?

 

[planet10]

6922 ~ 6DJ8 ~ ECC88

You can create an ~ 50-0-50 set of rails for the tube by using voltage doublers on each rail on the tube section of the XO and get much better results.

dave

 

[gingertube]

Look at the Music Fidelity X10D
Thread with schemtics here:
http://www.diyaudio.com/forums/tubes-valves/98207-musical-fidelity-x10d-schematic-2.html
The one I traced the circuit for (posted in that thread) used 6AQ8 but usually came with ECC88. +/-24V rails in that design.
Cheers,
Ian

 

[eelind]

For use with a 25⁺ - 0 - 25^- bipolar PSU, the tube to use is the 6GM8/ECC86. Constant current sink (CCS) load, at 2 mA. each, the pair of cathode followers and you're pretty much done.

Hi Elli,

do you have any schematics ?

Best regards

Éric

 

[pmillett]

Everybody assumes that tubes cannot be used on low plate voltages... but I suspect nobody actually does measurements to confirm their opinion. I have...

Even the 6SN7 can perform well at low plate voltages: http://diyaudioprojects.com/mirror/members.aol.com/sbench102/TubeMisc/6sn7lv.gif

ECC88 is actually remarkably similar to ECC86. Compare the plate curves. Sure, they are drawn at different scales, but both have zero-grid-voltage lines that are around 8mA at 25V.

I've used ECC88's down to 24V. And I've run them in an amp designed for ECC86 (http://www.pmillett.com/file_downloads/hybridamp_sch.pdf). They work very well at 25-50V.

But yes, ECC86 does work a little better. Of course there are also all the car radio tubes (12AE6A, 12FM6, etc.) that can be used at even lower voltages.

Pete

 

[Shoog]

The main issue with running an ECC88 at low voltage is that they tend to start drawing grid current which can destroy an expensive pot if direct coupled from a volume pot to the ECC88 grid in the first stage.
Other than that I tend to agree with Peter.

Shoog