Ecc89 / Ecc189

[maton00]

The photos do not show more than a small slice. I can assure you that I have used both types for about 40 years and in fairly large quantities. The PCC or ECC189 vari mu I use in my compressors and I use both sections as they are identical. The grid wind varies at about every couple of mm. Such that at bias volts of about minus 1 volt the gain is nearly that of the 88 version but by the time you have minus 8 volts the mu has droped to about a hundredth. As a cathode follower it is not quite as linear as the 88. However, for many audio purposes with low grid cathode volts it will work adequately. I have had some batches in the past that were incorrectly labeled. That is they were 88 in disguise.
A transfer curve vs neg grid volts shows that quickly. The grid spacing will vary about 2:1. On the machines I saw at EI the winder did about 4 turns then pitch changed and another 4 turns and more pitch changes with a stepped cam. Not perfect hence variations in individual valves. I have to go through lots to get several pairs.
So please get more photos to cover the whole length.

So it works like a remote cutoff pentode?
It may have an interesting behaviour for guitar effects

 

[popilin]

Mr Popilin can you sign an autograph to me?
You are one of the legends around this world.
But Send me an PM soon I will ask something about Messi against
Iran in the world cup

Don't make fun of me, we have the best football players around the world, but we don't have a team!

BTW, Messi is not Maradona...

Sorry off topic.

 

[disco]

vari mu triode

The photos do not show more than a small slice... The grid wind varies at about every couple of mm... The grid spacing will vary about 2:1. On the machines I saw at EI the winder did about 4 turns then pitch changed and another 4 turns and more pitch changes with a stepped cam. Not perfect hence variations in individual valves. So please get more photos to cover the whole length.

Ok, i will make better photos but even these shows almost whole lenght of the grid. Frankly i can not see change in pitch or spacing after four or so turns of wire on these photos.

An externally hosted image should be here but it was not working when we last tested it.

 

[gingertube]

I have one of the Hugh Dean's GK1 Preamplifiers. As stated above they run ECC189/6ES8 which is a variable mu tube with a pinout identical to ECC88/6DJ8/6922.

On tube per channel. The first ECC189 Triode section is run as a cathode follower at about 10mA this is the output buffer. The second triode section is run as a cathode follower as well, as a drone from an ss inverter such that the total current draw from the B+ is constant. The variable mu is not very apparent for 2 reasons, one is of course the 100% feedback in a cathode follower and secondly you need to swing a lot of current to get the tube to swing into the reduced mu part of the mu vs Ia curve. So there is some asymmetrical, signal level dependent distortion introduced.

The sound is very good with some "tube warmth" and a lot of SS Power Amps would actually benefit from using this preamp ahead of them, this is what I was using the GK1 for. I've since made a good tube power amp instead, so don't use the GK1 any more.

Various people described the sound as having some tube "magic" and if you are willing for me to blow of the fairy dust and say it adds "tube like distortion" to the audio path then yes it does. It "improves", "warms up", (add your own euphemism) the combined sound of it and a SS power amp.

I tried 6922 and 6DJ8 and ECC88 from various manufacturers in the GK1 and I can tell you that what ever "magic" is imparted by those ECC189 it does not occur with any of those "fixed mu" tubes.

Cheers,
Ian

 

[dady]

I agree with you Dude, that Sound" is a particular subjective impression that most of the people in this forum look for. But when you listen jazz or chamber or solo vocals, that is true, is easy music for some one amp and that warm is a taste that attracts our tastes may be, tarragon and pepper in more or less certain people like.
But the more we add pepper and tarragon to the sauce, so let's try then be loaded and to get those flavors to hide the original flavor.
When we speak of symphonic music, with complex passages with huge intermodulation becomes a drawback since the author harmonics promulgated in the score are replaced by others which may become not listenable.
I feel more than I think that we should try to put the least amount of active elements in the chain to the transducer. And if for reasons of force majeure, we should place more active elements in this chain, these were at least distortionary possible.
In professional audio mixers in the mastering consoles, What do they use?

 

[Ceglar]

ah.. it uses CF input/output and then inverts another CF which is left unused (but not unloaded)….

Odd. (harmonic cancellation)

yeah, ok.. what??

My time machine suggests it strips the CF sound away from CF via some cancellation via… heck, I dunno.

Yes. I blame the time machine.