ET3SE volume gain settings

[tonye]

I know I asked this before, and someone answered it, but I can't find it.

What are the gain settings for the ET3SE?

I think it's unity around 64 or something like that?

I'm having some issues using a somewhat picky SIT amp with 28db of gain... it has smoked twice already (*)... so I need to calculate the voltages I'm feeding it with a 2v input into the preamp.

(*) It's obviously not a commercial product... it's the bleeding edge... protection circuit you say? Bah, we don't need no stinkin' protection, we are fearless audiophiles!

[admin]

I think the high gain version is 54 db and the low gain version is 40 db. For cartridges of less than 1 mv output the high gain version is recommended.

[tonye]

Hmm... no, not the fixed gain phono stage. That's the gain from the cartridge level to the line level.

I'm asking about the gain of the line stage. The volume operates on a resistor ladder. I think each "step" is like 0.7db, or something like that.

There are 99 steps, I think. Unity gain is around 65 or so.

I need what the "digital steps" correspond to the line stage gain. That way, knowing what the voltage is in the line inputs, and knowing the gain on the line stage I can calculate the power output of the amplifier and figure out at what point I'm overdriving it.

[Joe Appierto]

I was unable to find the unity gain figure online for the ET3/ET3SE.

According to a review in Stereophile the 16LS2 I owned had volume/gain resistor steps of 0.67dB. They were almost always rounded to 0.7dB in most reviews I read. Unity gain for the 16LS2 occurred at about step 67 on the volume indicator.

It appears to have varied a little according to the CJ model. The Stereophile review of the ACT2 by Wes Phillips states:

"I could hear the resistor-ladder relays clacking away as I adjusted volume and balance, a sound I'd found strangely comforting in the ART, and did in the ACT2 as well. However, the ACT2's ladder uses 0.75dB steps over most of its range. As the ACT2 approaches full output, the steps are further apart (or so I'm told; I never got anywhere near that output level)."

In the same ACT2 review John Atkinson says:

"With the volume control set to "99," the maximum, its voltage gain was 20.5dB; the unity-gain setting was "76."

I know this doesn't directly answer your question but the information you're seeking is out there for some models. Maybe someone else can chime in specifically for the ET3SE.

[admin]

Hmm... no, not the fixed gain phono stage. That's the gain from the cartridge level to the line level.

I'm asking about the gain of the line stage. The volume operates on a resistor ladder. I think each "step" is like 0.7db, or something like that.

There are 99 steps, I think. Unity gain is around 65 or so.

I need what the "digital steps" correspond to the line stage gain. That way, knowing what the voltage is in the line inputs, and knowing the gain on the line stage I can calculate the power output of the amplifier and figure out at what point I'm overdriving it.

Sorry, I thought that this was phono cartridge matching. Never mind.

The CJ website generically lists "Gain: 25 db".

Not sure the exact volume control db per volume step but I find that most CJ preamps have been around 0.7 db per step (give or take a little, just as Joe mentioned as well).

[AnotherJohnson]

The CJ preamps tend to have a lot of gain, but as you know, how much gain it sounds like depends on the load.

[AnotherJohnson]

ET3/ET3SE Preamplifier
Specifications
Gain:25 db
Maximum output:20 Vrms
Output impedance:100 ohms
Distortion:less than .15% THD at 1.0 Vrms output
Frequency response:at unity gain2 Hz to more than 100Khz
Hum and noise:98 db below 2.5 v
Phase:
phase inverting
Tube complement:1 x 6922

[tonye]

Thanks guys.... I'll write this down somewhere.

Yes, it seems like my memory is not shot yet!

Combined with a DIY First Watt F4, ( unity gain ) the ET3E and PV9 will put out a lot of power! At full output into 98 ohms, the combination could put out 50w, but the F4 is current limited... so with a CJ tubed preamp ( 20Vrms max ) it will support 35 (8 ohms) wpc... which is quite a bit.

My concern now is driving the CJ preamp into a DIY Super SIT ( sort of a First Watt Turbo SIT-3 )... that one has a gain of 28db... so you can imagine that the amp will run into protection. I've already smoked it twice until the designer changed the value of the diodes following its front end ( too much current, fried a whole bunch of things...).

So, I'm sort of very, very careful, hearing all kinds of anomalies.

The current phono preamp will drive 2Vrms.