ElectroVibe Modifications Thread
- Thread starter Big Monk
- Start date
Raspymcnasty
Active member
is C7 supposed to be 10u as well? @bigmonk
So far I have the following mods noted.
R4 - 2M2 - Unity vol mod
R12 - 5M - Slow speed mod
R14/R15 - 2k7 high speed mod
C7/C10/C13/C15/C21/C23/C24/C26 - 10 uF - Low end mod
Q3/Q4 - 2N3904 - Reliability mod
Q14 - MPSA13 - darlington final phase stage mod
does this all look correct? or any suggestions for testing?
Big Monk
Well-known member
No. C7 is in the Speed section.
Raspymcnasty
Active member
I just wanted to double check since the explanation on the image on the first page explained you did it to C7 as well. Do my mod listings above look correct? Thank you btw.
Big Monk
Well-known member
That’s a direct quote from R.G. Keen, not me.
The caps noted specifically on the drawing and refdes are the ones to change because they actually correspond to the Electrovibe.
Big Monk
Well-known member
joelorigo
Well-known member
A couple more questions about mods. (Sorry I am hijacking this thread for my personal interests. Let me know if I should delete this post and start a new thread.)
I am interested in these mods: Unity Gain, Min/Max Speed, Low End & 2nd Phase, Phase Mix & Reliability & Darlington. There is no reason these can't all be implemented at the same time, right?
For the Min/Max Rate Mod, a resistor of 5M or above at R12 for extended range at slow speeds? Has anyone experimented with these values?
For the Phase Mix Mod, it is having one end of R16 & R17 connected to the board, connecting the other ends to a lug of 50k trim pot, then another leg of the trim pot back to the open R16 & R17 pads?
I am interested in these mods: Unity Gain, Min/Max Speed, Low End & 2nd Phase, Phase Mix & Reliability & Darlington. There is no reason these can't all be implemented at the same time, right?
For the Min/Max Rate Mod, a resistor of 5M or above at R12 for extended range at slow speeds? Has anyone experimented with these values?
For the Phase Mix Mod, it is having one end of R16 & R17 connected to the board, connecting the other ends to a lug of 50k trim pot, then another leg of the trim pot back to the open R16 & R17 pads?
Harry Klippton
Well-known member
Big Monk
Well-known member
There’s a lot to unpack here. I’ll do my best.
Unity gain is a no brainer and only a single resistor swap. Min/Max speed is also a resistor only mod. The cap mods are simply component swaps. Single resistor to Darlington swaps are straightforward as well.
Not that I know of. That’s directly cribbed from J.C. Maillett.
What would I do? I would get 2 75k ohm, 1/8w resistors. I’d attach each of them to the outside lugs of a 50k trim, along with a clipped lead attached to the wiper.
Find the junction of R16/17. There will be two acceptable pads to attach the wiper to. Attach the 1/8w resistors to the other ends of R16/17.
Big Monk
Well-known member
A stock ElectroVibe is like a stock Valve Junior: There are only a few things you HAVE to do to get it to sound great.
Honestly, Unity Gain and faster max speed are the only things that really beg to be done. It’s awesome with just that.
joelorigo
Well-known member
You did great thank you! Yes those component swaps are easy to grasp.
What is the "junction?" Is the wiper the center lug of the trimmer? As in:
Attachments
joelorigo
Well-known member
Good to know!
Big Monk
Well-known member
R16/R17 is a voltage divider.
The phase mix trimmer, along with the fixed resistors, replaces this divider.
joelorigo
Well-known member
Oh I see. Thanks! I was wondering about how to physically implement the mod. Maybe I'll skip this one if it doesn't make a noticeable audible difference.
Big Monk
Well-known member
It does. Worst case, just tack in the assembly and then use fixed resistors of the values:
New R16 = 75k + Rleft
New R17 = 75k + Rright
Where Rleft and Rright are the values measured from wiper to left lug and wiper to right lug after you’ve found the best null setting (strongest phase tone).
joelorigo
Well-known member
Oh It does? Hmm. I'm just not knowledgeable about the basics to understand what to do here.
In post #97 you said to build this (pic attached) then "Find the junction of R16/17." I don't know what "find the junction" means.
Attachments
Big Monk
Well-known member
On the unmodified ElectroVibe board, R16 and R17 form a voltage divider:
On this drawing, their junction is at Vout. On the board, the wiper of your phase trim assembly would connect at this junction.
It sounds like you should just try the stock circuit until you get your “sea legs”.
The Electrovibe really isn’t a beginner project.
On this drawing, their junction is at Vout. On the board, the wiper of your phase trim assembly would connect at this junction.
It sounds like you should just try the stock circuit until you get your “sea legs”.
The Electrovibe really isn’t a beginner project.
Feral Feline
Well-known member
Switch numbering
3 5 6
2 4 7
1 4 8
While the connections you've drawn will work, generally speaking the lugs on a 3PDT are typically numbered thusly:
1 4 7
2 5 8
3 6 9
I only bring it up because it may help in future communications with other builders about circuit wiring etc.
