Electrovibe Chorus volume

doublej

Member
so this may not really be trouble shooting, I have never had a uni-vibe and maybe this is how they work but on vibrato volume is full just with the effected signal. on Chorus I also get the effect but at a pretty decent volume drop. I have messed with the trims inside and have the volume maxed out. should I have a decent volume loss on chorus, not really perceived but obvious. I will get a pic as soon as I can
 
so this may not really be trouble shooting, I have never had a uni-vibe and maybe this is how they work but on vibrato volume is full just with the effected signal. on Chorus I also get the effect but at a pretty decent volume drop. I have messed with the trims inside and have the volume maxed out. should I have a decent volume loss on chorus, not really perceived but obvious. I will get a pic as soon as I can

This is an inherent part of the circuit.

I would tweak R4 until you get unity gain in chorus mode.
 
I'm sorry if I was being confusing. I was referring to where in the circuit to put the volume control. The harbinger is adapted from the deja vibe. I assumed people would use both schematics and decide a plan, probably wrong on my part. I guess my wife is right about me yet again...lol

I see.

The Volume control is in the same place on both circuits. I see the Harbinger adds an additional option for an input buffer, but it seems much easier and less invasive on the Electrovibe to simply increase R4 until you hit unity gain at a suitable place on the dial.
 
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Quick question fellas. I gigged mine this weekend and the tone was glorious, but I did notice the small volume drop. Would R4 need to go up or down to increase volume?

Up.

The R1/R4 divider can be tweaked to allow more signal to pass into the circuit. Stock, it lets 68% of the signal get through. So if you find that you are having volume issues, you can tweak R4 up. For example, 100k goes to 82%, 250k to 92%, 2M to 99%, etc.

I'd maybe tack in a 100k pot and see what gets you to unity, or a volume in general that works for you, then replace with the closest fixed resistor.
 
Up.

The R1/R4 divider can be tweaked to allow more signal to pass into the circuit. Stock, it lets 68% of the signal get through. So if you find that you are having volume issues, you can tweak R4 up. For example, 100k goes to 82%, 250k to 92%, 2M to 99%, etc.

I'd maybe tack in a 100k pot and see what gets you to unity, or a volume in general that works for you, then replace with the closest fixed resistor

Ok, thanks, will report back.
 
One more question before I fire up the iron....should I go 2M? Then I have the volume pot to dial it back if it's too much. Also, if I was to use a pot to dial it in, I would use lugs 2 and 3? Sorry for the newb questions, Still learning
 
One more question before I fire up the iron....should I go 2M? Then I have the volume pot to dial it back if it's too much. Also, if I was to use a pot to dial it in, I would use lugs 2 and 3? Sorry for the newb questions, Still learning

You could go 2M. Going higher is just going to move unity down the dial.

Yes on the pot. Since you need a variable resistor, use either 1 and 2 or 2 and 3.
 
Up.

The R1/R4 divider can be tweaked to allow more signal to pass into the circuit. Stock, it lets 68% of the signal get through. So if you find that you are having volume issues, you can tweak R4 up. For example, 100k goes to 82%, 250k to 92%, 2M to 99%, etc.

I'd maybe tack in a 100k pot and see what gets you to unity, or a volume in general that works for you, then replace with the closest fixed resistor.
I know you didn't design the circuit but why would stock only let 68% through, I mean why would someone want a vol drop? is that how the original worked?
 
I know you didn't design the circuit but why would stock only let 68% through, I mean why would someone want a vol drop? is that how the original worked?

Voltage dividers are common in circuits to drop the signal down to manageable levels. For instance, the original Epiphone Valve Junior dumped something like 50% of the input signal with a 68k/68k voltage divider.

I doubt they designed it to not have unity gain. At the time, many artists were playing through very loud rigs and frankly would have compensated in other places on the fly, i.e. volume knob manipulations.
 
Hello there, Just giving my little feedback on this topics. I was also finding that the Electrovibe had a low output level. Then I found your thread and tried to swap the R4 - 47k to higher value. Experimented with a 1M Pot, which I found still too weak. Then with a fixed 2M resistor : this one is definitely the way to go in my opinion. Make the Electrovibe goes from discreet to where I should have hopped it would go. I'd say it's going above unity around 2 or 3 o'clock. Allowing a slight boost of volume when maxed out. Hope this helps for future builders :) Anyway thanks to you for the tips.
 
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