EQD Monarch Boneyard Edition on EL Tangerine Board

Fingolfen

Well-known member
So I have a few of the EL Tangerine Boards to make up the EQD Monarch, and there were some suggested mods that seem to line up with the Fuzzdog Orange King Drive "Boneyard Edition" - but it looks like the Fuzzdog version makes a couple of additional changes not mentioned on the Tangerine. I've compared the schematics (see scribble below) and think the changes to the Tangerine would need to be as follows:

Per EL: Replace C10 and C12 with 10k resistors, remove R11 and replace C9 with a jumper.

In addition: Replace Q3 with a J201, replace treble and bass pots with a B1M rather than an A1M.

Am I missing anything?

EQDMonarch001.jpg
 
These mods you mention look ok, but I have not simulated or tested them. C11 is backwards on the Tangerine sch.

Q3 can be just about any JFET as long as Vp is less than 3V and Idss is greater than 1mA. I see no advantage in using J201 for Q3. Whatever you use, test it first.

I prefer a JFET for Q1 because it is much quieter than a MOSFET.

The taper of the BASS & TREBLE pots is user preference. They both don't have to be the same taper. A-taper will spread out the bottom end of rotation but gets touchy above 3:00. B-taper will spread out the top end of rotation and make the bottom end of rotation touchy. Either one is a compromise.

Plan on selecting Q2, R14, or both to get Q2's Id between 1mA & 2mA.
 
Thanks for the quick response! I see what you mean about C11, I was so busy looking at the component values I missed the polarity shift. I'll double check and see if that's duplicated on the silkscreen or not.

I think my new Peak Atlas should get me Vp / Idss on the JFET. Any JFET recommendations for Q1?

What's the easiest way to measure the Id on Q2?

Here's the Fuzzdog schematic / BOM I pulled:

Fuzzdog Monarch.jpg
 
Any JFET recommendations for Q1?
Something with Vp below 2V. I like PF5102 because they are high gain. You can try PN4393 or MPF4393. You might find a 2N5952 with Vp below 2V.

Look at the Viceroy schematic. If you use as JFET for Q1, then you will need to delete R3, increase R6 and put a cap in parallel with R6. You should also put a resistor or trimpot in series with that cap to limit the gain if you want to be able to play clean. Try 1K for starters.

What's the easiest way to measure the Id on Q2?

Measure the voltage across R14 and divide by R. Ohm's Law.
 
Something with Vp below 2V. I like PF5102 because they are high gain. You can try PN4393 or MPF4393. You might find a 2N5952 with Vp below 2V.

Look at the Viceroy schematic. If you use as JFET for Q1, then you will need to delete R3, increase R6 and put a cap in parallel with R6. You should also put a resistor or trimpot in series with that cap to limit the gain if you want to be able to play clean. Try 1K for starters.



Measure the voltage across R14 and divide by R. Ohm's Law.
Thanks! I'll play around with it...

... I was hoping to be able to get Id before I put things in the circuit... but yeah... Ohms law always works! :D
 
You can breadboard that part of the circuit and dial-in the bias, then solder the selected parts onto the PCB.

You don't have to requote my posts in their entirety.
 
Thought of that right after I hit the enter button... lol... I may just breadboard the whole thing and so I can have a reference for my builds. Then I can test the whole thing before soldering it. I figure I can leave the passive components in place and adjust as needed, then transfer to the board.
 
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