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Ecc89 / Ecc189

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#2
Hi,

Would an ECC89 / ECC189 be able to go as low as an ECC88? (I mean the voltage).
Click to expand...

First of all ECC89 and ECC189 are not one and the same type.

Secondly, neither one is suitable for audio at least not domestic applications.

These are variable mu tubes used for automatic gain control (AGC), studio gear uses them sometimes in compressor/expander circuits.

PS: Mr. Hugh from AKSA has a preamp kit, which utilises an ECC189.
Click to expand...

He does?

Cheers,😉
 
#6
Hi,

Anyway, back to the topic, Can it go as low as an ECC88?QUOTE]

Since the ECC189 is basically a ECC88 with variable mu (all that's been changed vis a vis the ECC88 is the grid), yes it can.

As for its use by Hugh Dean in the AKS range, I understand from reading the links you provide the ECC189 is being used as a cathode follower.
In that case the variable mu feature won't have any impact on the performance.

Cheers,😉
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#9
Are you sure, Eli?
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No, I'm not certain; that's why I said "IIRC". I've been wrong before and I'll be wrong again.

What I recall makes sense. The 6DJ8 and its relations were designed to be used as cascode VHF front ends. Having a fixed mu section "upstairs" and a variable mu section "downstairs" for AGC would work WELL.
 
#10
Hi,

Having a fixed mu section "upstairs" and a variable mu section "downstairs" for AGC would work WELL.
Click to expand...

Indeed it would but in the case of the ECC189/6ES8 they didn't pay any attention to that aspect other than recommending section 1 as the input (a-g-k) for the cascode.
Looking at the internal wiring diagram and at minor interelectrode capacitances shows why.

Other dual triodes designed for cascode use sometimes have slightly differing sections but nothing of the kind that would have any impact on a CF design anyway.

One of the finest developments of cascode triodes was the ECC200 (no idea if it has an American equivalent) which even had neutrodynizing shields. Truely impressive for such a small tube.

Cheers, 😉
 
#11
The ECC189/PCC189 have both sections as Variable mu triodes. The grid is wound differently to the ECC88/PCC88 type.

Have use for 20 years the 189 in studio compressor/limiter products.

the ECC89 also has both sections as Veri mu but is an earlier tube based on the ECC84.
 
#12
ECC189 for audio.

Found today this discussion on ecc189 ,btw i tried ecc189 in few preamplifiers
and frankly they sounds quite ok,no audible distortion ,i heard it depends of
circuit but in most cases ecc189 can replace ecc88.
Maybe these pictures of ecc88 and ecc89 grids could be interesting to see.
I ve made it on Leica microscope magnification 40X.
ECC189 have closer spaced grid wire winding ,i guess for amplification
of weaker signals .Removing frame grids without damage from tubes was
very tricky.
 

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#13
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.
 
#14
ECC89 also has complete different pinout, this is to similar or identical to 6dj8 with different pinout the russian number is 6N24P or 6FC7.
ECC189 is variable mu used on AGC in TV.
I used this tube on step of 6DJ8 with no sonic changes. Maybe i becoming deaf
 
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#15
Well done. E or PCC89 was as I said right at the beggining of this tread a few years ago was a vari mu of E or PCC84 family. Generally fairly microphonic hence I do not use. Have a hundred Mullards or so.
I was talking about -CC189 and -CC88 family of frame grid valves.
 
#17
If they were wound very evenly along whole length, then the valve was not a true E or PCC189. As I said I have had some that were in reality 88 types.
If you PM me with your address, I will post a genuine example for you to photograph.
 
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