Author Topic: Janus preamp full components list?  (Read 253 times)

Offline Justin Waterhouse

  • Pre-Piano
  • *
  • Posts: 7
    • View Profile
Janus preamp full components list?
« on: October 02, 2018, 05:01:52 PM »
Hello everyone,

There is a lot of great information out there for the Rhodes amps, and repair kits etc., but what if you want to make a Janus preamp from scratch? The schematic has some info missing and I don't have a Janus preamp here to copy or give to an electronics wizard to decipher.

On the internet I saw a Dyno my piano preamp on veroboard that someone made, with all the components annotated on the diagram and listed to the side. What a kind Gent! Looks like that might be quite easy to make now.

Does anyone have anything similar for a Janus preamp that they would be willing to share?
Next week I'll probably be asking for a Peterson parts list... with modern equivalent spec for the Orp61 photoresistor and bulb

Thanks in advance kind people,

Offline sean

  • Mark II
  • *****
  • Posts: 772
    • View Profile
Re: Janus preamp full components list?
« Reply #1 on: October 04, 2018, 11:58:40 PM »

Well, you didn't say which of the three Janus preamp circuits you are interested in building.  But in any case, the hardest part to source is the LDR.  Get your hands on that, and the rest is pretty simple.  Vintage Vibe has them.  But this one obsolete and expensive part could ruin the economics and fun of this project.

Also, I really wonder why in the world you would want to build a Janus preamp.  The Janus preamp never gets much love online, everyone says that the Peterson tremolo is tons better.  If you want to build one because you want a really good preamp for your Rhodes, you would be much better served by spending your money on a modern preamp and a tremolo/leslie simulator. 

If you want to build the Janus preamp as a lesson in electronics construction, then okay, I guess.  It is a pretty good challenge, because it is seventy-some components, with five pots to mount on a front panel while mounted to the circuit board.  I don't think I would enjoy building something this big on veroboard, but you could design the board using something like DipTrace, and then send off the Gerber files to have it fabricated.  That is a lot of work, and it will be nearly impossible to get it right the first time.

Then you also get to build the power supply, that's the only part that I can help you with...

After all that work, you will have a mediocre single-purpose preamp.