what double triode is less microphonic ?

[inertial]

Hi,

More accurately, I'm searching info about a near zero microphonic medium mu double triode. Low Rp is requested.
candidates are
E182 CC , ECC99, 5687, 6H30 or others
I have some E288CC philips SQ but they ring like bells
I can considerate also single triode.
I know EC8020 is the best but they are ultra expansive !
I appreciate any kind of suggestion
Thanks for help,

Paolo

 

[Frank Berry]

Have your tried a 6922?

 

[inertial]

Yes frank,
my sowtek is perfect but I would just half Rp .
The problem seems to me that these sovtek 6922 are sort of unique,
others brand ECC88 are more or less microphonic.

cheers,

 

[cypher]

I'm using 6n6p which is replacement for E182CC and CV5766 and this tube doesn’t microphonic at all. And sounds very very good.. ;-))

 

[inertial]

Hi cypher,

please what is the brand of the your 6n6p ? Looks very interesting

 

[cypher]

6n6p this is NOS Russian tube, easy to find on eBay ant very cheap to. I don't really know name of company which was making them.
BTW. Also 6n1p-ew (military version) is very good tube ;-))

 

[inertial]

Thanks cypher, very appreciated info

 

[inertial]

Cypher,

excuse me, is it 6n6p pinout the same of E182CC ?

Paolo

 

[Wavebourn]

A pair of 6J32P triode strapped is the best double triode in terms of microphonics.

 

[kenpeter]

I xray'd some Amperex, Sylvania, and Telefunken 6dj8's.
Most also bearing the ECC88 stamp. In the thread "I
got waay too many 6dj8's" you will find more photos.

My observation was that the plate structure viewed
straight down from top (right through the getter),
the plate looked like a weirldy bent tuning fork, or C
with sligthly overlapping ends that don't actually touch.

Unless the insulator at top or bottom has a grip that
is effective to damp out that mode, the plate itself is
not a complete closed circle, what supports the open
end of the tuning fork?

---------------------edit-------------------------

I think this was the relevant angle of view

 

[Karsten Sømand]

Hi inertial,

Here are some figures for you, but unfortunately only for a few russian tubes. I have hoped for some data for the 6H30Pi but it seems as if microphonic noise for this tube is not stated in any data sheets (?).

Here are my findings from different suppliers on the Internet:

6N1P-type, Ra = 2 kOhm

6N1P: max. 100 mV
6N1P-IV: max. 80 mV
6N1P-EV: max. 50 mV


6N6P-type, Ra = 0,5 kOhm

6N6P: max. 100 mV
6N6PI: max. 100 mV
(I don´t think the 6N6P tube was / is made in IV or EV versions).


6N23P-type, Ra = 2 kOhm

6N23P: max. 150 mV
6N23P-EV: max. 75 mV


6J32P: max. 80 mV (no info regarding Ra)

I don´t know how these figures compare to European and / or American types of tubes but it looks as if the 6N1P-EV is the best one of the tubes shown here.

But, I see Wavebourn has a suggestion - maybe he is able to inform in details how much better the pentode 6J32P will perform when triode strapped?! I think it sounds very exciting.

Kind regards

Karsten

 

[Wavebourn]

I can't tell in details, it was my guess since I use 6J32P as a pentode and it is quieter than 6N1P and 6N2P.

Edit: 6S62N is very quiet as well, I used them with a heavy steel nut glued around by epoxy long time ago in condenser microphones.

 

[cypher]

Cypher,

excuse me, is it 6n6p pinout the same of E182CC ?

Paolo

Yes, as far as know they are the same, please have a look at data sheets and compare them in details 6n6p is more demanding for heater current and there are some differences in pin out but socket is the same.

You can compare data 6n6p and E182CC:
http://www.mif.pg.gda.pl/homepages/frank/sheets/113/6/6N6P.pdf

http://www.mif.pg.gda.pl/homepages/frank/sheets/009/e/E182CC.pdf

 

[Bas Horneman]

The 6N1P-EV is definately very low in microphonics. Even when flicking them with the fingernails..you hear absolutely nothing coming through in the sound.

The 6n6p is also good...and has a low Ra.

The 6J32P won't have a low Ra methinks.

 

[inertial]

Hi,

I want to thanks all the guys here for precious info! I appreciate
indeed
I'm very interested in these 6n6p. If I understood correctly I can't
swap istantaneously from 6n6p to E182CC Siemens( my friend have a pair, never tried) but I have to "rewiring" for different pins position.


Cheers,
Paolo

 

[Karsten Sømand]

Hi inertia,

Please check your PSU first.

The Siemens has an Ih of 450 mA - the 6N6P is 750 +/- 70 mA - almost double the current (!!!). As a rule of thumb you can say that the russian tubes are (far) more demanding regarding Ih, in general.

Let us hear your opinion when you have tried this out.

Kind regards

Karsten

 

[JosM]

Hello Inertial,

I use e88cc brand Philips in a MC (moving coil) amp Sensitivity is 100 uVolt. The plate voltage is low 25 volt with a CCS (Constant current sourse) also with e88cc. No microphonic at all. If you are interrested in the schematic I can send it to you.

regards,

Jos

 

[Bas Horneman]

I use e88cc brand Philips

Low Rp is requested.

 

[inertial]

guys, you are so kind

Jos,

Thanks, but I am digital boy only

Karsten, first I am incompetent with electronics, mine friend do work
my absurde ideas for me . But he also need guidance so I ask for
both
My plane is to start with E182CC( half R half L) as simple common cathode , B+ is 200-250 V disponible. I need the value for plate resistor and cathode resistor .
Requested is low Zout 1500 ohm or less and low THD for a maximum output of 10V rms 1% if possible .
If the Siemens will be microphonic, I'll restart with 6n6p .

Cheers,

 

[JosM]

Calculation program

Hello Inertial,

I will send you by e-mail a calculation program (Excel) wherewith you can calculate the plate en cathode resistor.

Jos