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Please post your experience with 6C45 and 6H30

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A

audiowolf

Member
Joined 2007
The 6H30 suck I removed a bunch of them in a BAT preamp, VK51SE and replaced them with EC99 from JJ Tubes, made a few resistor changes too...MUCH better bass extension, far more clarity in mids and far lower microphonics issues. 6H30 had horrid microphonic problems..not just mechanical pick up, but worse yet, excitation from the signal passing through it. Tested some with a single pulse and saw about half a second of 'mechanical' ringing in the output induced by the pulse and its electromagnetic field moving around the parts, which then just vibrated on for a while .

My suggestion for 6H30 is to take them to your local firing range and set them up at 50 feet and practice with a 22LR cal pistol....at least they would be good targets for developing your aiming skills.

No experience with the 6c45p......but Do look into the ECC99 for dual triode medium mu. It will do 20 ma per section easy.

cheers
 
I

inertial

Member
Joined 2004
Oh thank you very much audiowolf!

I like decise positions :D
6H30 forgot !
I am wondered how it is possible a serious brand like BAT, very regarded here in Italy, have emploied it :hot: Incredible.

At the moment I use 6N6P this is supposed silmilar to ECC99,
I believe. Quite satisfied ,for now.

Wow it seems to me 6C45 is my last possibilietis but I have a bad
expecting about microphonicity becuse his High transconductance.
Curious to read others experiences.......

Cheers,
Paolo
 
I

inertial

Member
Joined 2004
Gluca said:
I replaced ECC99 with 6H30. No microphonics at all. I preferred 6H30. I didn't like 6C45pi, it sounded "metallic" and "hard" if you allow me to say so.

6N6p can be a valid replacement too (and cheaper).

Ciao
Gianluca
Click to expand...


Thanks, Gianluca.

So opposite opinions here. Interesting :xeye:
Was your 6C45P even slightly microphonic ?

Paolo
 
P

pistoljoe

Member
Joined 2005
Or you can send those 6H30s to me, instead of blasting them into little pieces.

I also preferred the JJ ecc99 to the 6H30, until I ran the russians fat. Dialing them above 30mA, with Pimm's CCS, made them sing with great bass.

The 6с45п you need to handle with kid gloves, like the 417 and 437. I wouldn't recommend unless you need the tube for what it does so well, and you're willing to work at it.

Joe
 
I

inertial

Member
Joined 2004
pistoljoe said:
.

The 6A45? you need to handle with kid gloves, like the 417 and 437. I wouldn't recommend unless you need the tube for what it does so well, and you're willing to work at it.

Joe
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Hi Joe,
perdone me , my english is poor that I have not entirely understood
your comment . Why 6C45 is so "fragile" ? At cost to be annoing I'm interested in microphony first, then the rest maybe is workable :confused:

Cheers,
Paolo
 
dsavitsk

dsavitsk

diyAudio Member
Joined 2005
diyaudio.ecp.cc
SY said:
By "fragile," I'd guess he means "prone to burst into oscillation unless designed and constructed with great care."
Click to expand...

One symptom of which may be microphonics. My experience on a limited sample of these is that some of them oscillate audibly no matter what you do, and some don't, even with non-ideal layout.

The trick to getting good sound from this tube seems to be keeping the current low (~12mA). The problem with keeping the current low is that you lose the high Gm, low rp benefit of the tube. Indeed, it may be that at high Gm they nearly always oscillate which would account for the harshness people report.
 
rdf

rdf

Member
Joined 2004
dsavitsk said:
The trick to getting good sound from this tube seems to be keeping the current low (~12mA).
Click to expand...

Double bingo. Builders wick this tube up based on its '7 watt' Pd but I've generally found higher harmonic distortion products rise rapidly at high currents. Currently on the bench I have one choke-loaded @ 8 ma and direct coupled into a 2A3, using an 8 ohm resistive divider and AKG K 701s as monitors. It's anything but harsh. Below 1 watt all harmonics above the third are over 90 dB down (5k OPT).
 
Gluca

Gluca

Member
Joined 2004
rdf said:


Double bingo. Builders wick this tube up based on its '7 watt' Pd but I've generally found higher harmonic distortion products rise rapidly at high currents. Currently on the bench I have one choke-loaded @ 8 ma and direct coupled into a 2A3, using an 8 ohm resistive divider and AKG K 701s as monitors. It's anything but harsh. Below 1 watt all harmonics above the third are over 90 dB down (5k OPT).
Click to expand...

Triple bingo! I ran it at 15-20 mA (yes, to get high gm and low Rp) and it was indeed harsh. No oscillations with a small R at the grid pin.
 
V

Vlauga

Member
Joined 2005
My five cents.
There are two different tubes 6H30P:

1. modern 6H30P;
2. original, NOS, Soviet 6N30P-DR.

These are two absolutely different tubes.
The new tube 6H30P on sounding is similitude 6H6P.

Old Soviet 6H30P-DR sounds it is very pellucid, very precisely, surprisingly. At level of 45 tubes. Level of the third harmonic - 80dB.

There is no comparison with modern 6H30P. Now a modern tube make not clearly from what materials and under drawings is faster similar on 6H6P.

By the way, term of the secured service of the Soviet tube 6N30P-DR is secured 10000 hours.
 
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