Tremolux depth pot range help

[Dandrix]

My depth pot range is short to say? DoesnÂ’t really change anything till about seven on the dial, ItÂ’s a 5g9 tremolux. I am using a 3rma pot with a 160 ohm res to ground. I have -19 volts on each side of the wipers. Measured middle lug at full depth (12) measures -29 volts. I would have to double check this measurements.

Trem works great with the speed at 2/3 and the depth 10-12 range. Should it have more range (or do something a little more noticeable) before 10? Ok, 7-10 has a little effect going on.

I have tried a couple different 12ax7Â’s

Thanks for the insight

[nosaj]

My depth pot range is short to say? DoesnÂ’t really change anything till about seven on the dial, ItÂ’s a 5g9 tremolux. I am using a 3rma pot with a 160 ohm res to ground. I have -19 volts on each side of the wipers. Measured middle lug at full depth (12) measures -29 volts. I would have to double check this measurements.

Trem works great with the speed at 2/3 and the depth 10-12 range. Should it have more range (or do something a little more noticeable) before 10? Ok, 7-10 has a little effect going on.

I have tried a couple different 12ax7Â’s

Thanks for the insight

Is this one you built?
Is it a linear or a Log pot?

nosaj

[Enzo]

I don't follow your report. The pot should be 250k, is it? What does 160 ohms to ground mean? 160 ohms from where? I see no reason in the circuit for such a low resistance.

Turn the trem off, you should see about the same DC voltage on all three legs of that pot.

[g1]

I'm not understanding the description either. Schematic attached.

[Dandrix]

Is this one you built?
Is it a linear or a Log pot?

nosaj

Yes I built it, it’s a 250k. I think linear?

[Dandrix]

Yes , my bad 250k.
The speed pot has the 160k resistor

[Dandrix]

Can’t open your attachment but, I screw up, it was a 250k pot.

[g1]

Like Enzo said, same bias voltage should appear at all 3 legs of the depth pot. If the bias isn't right, the trem effect is not going to work properly.

[Dandrix]

So, the operation of this depth pot should be linear for all across range affect. Audio pot won’t kick in till about seven ish on the dial? It does Not mean my Trem is not operating properly?

[Dandrix]

Like Enzo said, same bias voltage should appear at all 3 legs of the depth pot. If the bias isn't right, the trem effect is not going to work properly.

I have -19 volts on each side of the wipers. Measured middle lug at full depth (12) measures -29 volts. I would have to double check this measurements.

So if my measurements were right, would this be correct at full range -29 volts?

[Enzo]

With the trem turned off, you should get about the same -29v on all three legs of the pot regardless of setting.

When the trem is turned on, the varying voltage from the trem circuit will make your voltage readings wobble up and down.

I don't know how you can have -29v on the center leg and lower voltage on the two end legs.

In a pot, there is one wiper, and that is the center terminal. The other two terminals are not called wipers.

[Dandrix]

So, I am getting -19 v on either side of the wiper
I have a 250ka pot, I have a 12ax7 EH (new). Voltages 238v 1.9v 0 234v off of tremo tube.
My pwr tubes have -19v off of pin5
Plate voltage is 375/ 376v
Screen is 369/367v

Is my negative voltage on the load side?
Tremo really doesn’t engage till about 7/8 on the dial. 10 for sure

[g1]

Can you post some pictures of the insides of the chassis?

[Dandrix]

Can you post some pictures of the insides of the chassis?

https://music-electronics-forum.com/...l=1#post556065