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I made an even smaller SMD version with headphones amp, here are two clips:

https://www.youtube.com/watch?v=_r0buBAmZOk
https://www.youtube.com/watch?v=0lucVJucm60

Hi!

I have some PCBs left, 10Eur each, EU postal fee 6Eur, US/Canada 8Eur. Use Paypal (friends&family!) for payment, email: janne.isotalo@saunalahti.fi and send me your address.

Build docs can be downloaded from here:
https://www.dropbox.com/s/64tkrrld0f73xo7/JSI-PetersonPreamp-BUILD.pdf?dl=0

Some IMPORTANT build notes:
- Please build it following the order of the build guide pictures.
- You need be able to drill and file the Hammond 1590BB enclosure. PCB can be used as a "drill guide".
- Only the SPST (/SPDT) foot switch needs wiring. Pots are soldered LAST! and cut the component legs as short as possible under the pots.
- BOM has part numbers for Mouser and Tayda Electronics. Some components have only one source and need to be bought from there. Vactrols need to be bought elsewhere, like: Thonk, Synthcube, Musikding, Banzaimusic, Tubesandmore, Ebay, etc.
- You can build the pedal without the Delta DC-DC converter, but then you should use a quality +24VDC linear power supply.
- Pay attention to the polarity of your power supply. Header J5 can be used to switch between "center positive / negative". The most of the guitar pedal power supplies are center negative. The most of the regular DC power adaptors are center positive.
- Current draw is around 25mA (+24VDC). You can test the unit even with a 9V battery (use clip connector), but the battery probably will not last many hours.
- Have fun building!

 

The whole project started with taking a closer look at Vintage Vibes stereo vibe preamp, which I had purchased long time ago. I got interested in how it differs from the original Peterson schematic and by back-engineering I found out that the only difference was in the tremolo section (bulbs -> VTL5C1's). This simply been just some resistor value changes and a slew generator to simulate bulb behavior.

I opened up their power supply (that red one) and noticed that there's only that mean well supply and some jacks. Preamp current draw is only <30mA with the vactrols. For my pedal I used DC-DC converter (9-36v -> 24v) and now it powers even 9v battery, wall wart being a better option of course.

I designed a pcb and used parts that fit Hammond 1590B enclosure, so no wiring needed. Only expensive parts on the VV preamp (besides vactrols) are the pots, so for this pedal I used single pots instead of dual concentric ones. It needs C50k for depth control (can be modded with b100k&100k res) but for speed control I left out the 82k res for the "slow speed switch" and used b100k instead. So, this pedal has larger scale, which I liked more.

That's basically it. I'll not be sharing gerbers but I can sell pcb for personal use. This as a courtesy towards VV, they do excellent work and I don't want to harm their business. PM if interested.

Cheers,
Janne

Mean Well RS-15-24 is the one inside the Vintage Vibe power (red color). It's easy to throw inside a hammond enclosure. Find that 4 -pin DIN female connector and wire two 1/4" jacks and you'll have the same box.

BTW. The vactrol version of this peterson preamp (VV preamp) has <30mA current draw.

Hi,

I made a DIY peterson preamp pedal. It uses vactrols (like VV preamp), otherwise it's identical with original Peterson. Here's a quick demo which compares it to VV model:

https://youtu.be/d2y6bqWHQtU

Best,
Janne

https://youtu.be/d2y6bqWHQtU

Here's my diy project demo.

Hi! I just bought CP-70 and I'm also going to retolex the whole thing, hopefully this summer. Looking forward to this project. If you guys have pics/info anything, please share! Thanks!

Cool!  Much better than mine dirty fast solution

https://www.youtube.com/watch?v=bv1raPnFmvg

I found this on my cellphone, here's the original note from where I made the schematic. I think those caps were 10uF tantalum caps.

Nice job Sean! I'm no expert by any means, so I'm happy to see someone more qualified to continuing this.

I measured the caps with a semi-cheap DMM, so the cap measurements are "guidance only" -values (and the C2 obviously wrong in the schematic: NOT 11nF, 11uF). My idea was to breadboard this and try different components, but since you already did this and even showed plots that shows how it clears the 200Hz "muddy-area", I feel that there's no need for more prototyping. Thanks a lot!

One thing that I didn't remember to measure was the dimension between the the pots, does anyone have this? I think it's the same dimension as the mounting holes in MK1 name rail? Would be fun to draw and order a prototype pcb, even though it's just a basic eq... but it might be hard to find a concentric 1M pots? I think Bourns have them on Mouser.

Best,
Janne

Here's my unverified veroboard layout. I figured that since I don't have much time I could just share this if someone likes to try it out. A wise move would be draw a pcb with 9mm alpha pots with same mounting holes as in mk1 panel.. Maybe I'll do it someday

Thanks! I turned out that the pot wasn't broken, problem was elsewhere, now solved. I did some backengineering on that rhodie preamp and found out that it's really a basic active eq with one ic. I lifted and measured the resistors and capacitors, and drew a basic schematic.

Hi all!

Does anyone know where to find those old Bourns potentiometers? The volume pot is broken and the legs are little peculiarly shaped on these pots. Since the pcb is mounted with the pots to the name rail, I wouldn't want to use different type of pots... if there's no exact replacement pot available, then there's no option.

All help appreciated, thanks!

Cheers,
Janne

I made this based on the same schematic. Works fine, but since there is like 20x boost on highs, it's pretty noisy.

https://www.youtube.com/watch?v=Cf-HroHJsQo

You can get pretty similar results with the bbe sonic maximizer. And if you are more into chorus than the suitcase tremolo, CE-1 is the king of choruses for Rhodes, in my opinion.

Cheers,
Janne

For synth diy work I have used this measuring technique (VBE):

http://www.dragonflyalley.com/images/TransistorMatching/ianFritz-transmat0011_144.pdf

But I'm not sure if it's needed here. In synth diy these are used in the expo convertors,  in "volts per octave" -> current. For example, precisely controlling voltage controlled oscillators or filters, etc.

That would be great! And please record same straight from the harp rca for reference!

Thanks! I was hoping that someone somewhere would have back engineered this. Seems like a IC, resistors, two tantalums, couple of diodes. My version is opened from the bottom side, so all the pcb traces can be seen. Maybe someone was trying to fix it before.

Does anyone have a soundclip of this preamp somewhere? I'd like to hear it in action before ripping it apart for "inspection"

Of course..but I was hoping to get a veroboard diy version of this quite simple preamp. Seems like a couple of tantalums, diodes, 1 ic and a bunch of resistors..

Hi all,

Has anyone back engineered this "rhodie preamp"? Or are there schematics somewhere? All the components are painted black. I found one in a mk2 stage 73 (plastic keys, 2482), first one that I've come across here in Finland. It's not working and since I've never heard one I'd really like to repair it! All help appriciated!



Cheers,
Janne

I'd say the usual problem is more in the low mids (around 200hz) than in the bass. One of the mods I'd still like to add to this combo is one parametric eq to clear that low mid area. I'm not sure (yet) what freq's the eq in stereo vibe pre amp (=peterson) actually effects. Would be interesting to reverse engineer it and compare it to the original. At first glance the eq section of the pcb seems to be quiet exact with the original peterson model.

If you are talking about the vv stereo vibe pre amp, I'll have to say that with the headphones amp it's really the perfect add-on for stage piano. Forget the passive electronics, the bass knob only works as a attenuator, cuts out the bass.

Here's a clip of me playing my restoration project, MK2 stage -80, thru vv stereo vibe pre amp, with bbe sonic stomp & ehx small clone phaser (clone). Direct stereo line output from the vv stereo vibe. And it sounds exactly like this with headphones. Sweet.

https://dl.dropboxusercontent.com/u/8085136/Rhodes-stuff/Rhodes-phaser.mp4

Cheers,
Janne

Thanks for sharing!

Speaking of Boss CE-1, I recently made a clone using all original parts. Here's a short comparison video (clone vs original) with jupiter-6 and rhodes markI:

https://www.youtube.com/watch?v=CZSkfZO0OzY

The "stereo" in CE-1 is actually left dry - right wet, when using both outputs. In mono it's mixed without a potentiometer to change the dry-wet ratio. In my opinion CE-1 and CE-2 sound totally different with rhodes and the winner is clearly CE-1. Add BBE sonic maximazer with the CE-1 and you're half way there even with poorly adjusted rhodes.

Thanks! Only thing I had to change is the power section. I used the Ray Wilson design (half wave) with 15v regs, so it uses 12vac or 15vac ac power adapter. Musicfromouterspace.com

We couldn't really hear any difference, so if someone does, please share your opinions!

Hi all!

I thought I'd share this little Boss CE-1 comparison video. I've been working on a clone pedal and I'm quite pleased with the results.

https://www.youtube.com/watch?v=CZSkfZO0OzY

It's based on this:

http://www.crazy-patroche.com/article-etude-du-chorus-boss-ce1-119548543.html

Cheers,
Janne

Hi all!

Has anyone built a custom suitcase from a stage piano? I'm considering this for markII stage. Woodwork is no problem.

My plan is:

- suitcase legs
- ken rich -type of mod for the pedal (wurly type) http://www.ep-service.nl/pull-sustain-mechanism
- stage piano would have VV stereo vibe
- VV power amp module http://www.vintagevibe.com/collections/fender-rhodes-parts-electronics/products/fender-rhodes-power-amp-module?variant=899488607
- 4 speakers

What else would I need for it? Side panel?

Cheers,
Janne

Back checks....it's also definitely a matter of taste, playing style, etc. If you are a pro player who is used to grand piano type of action, a rhodes with bouncy keys can get you frustrated in no time. But if you are still searching for the sharp eleventh on a dominant chord, then you are probably ok with it ;-)

They need to be adjusted with patience, and stationary studio environment would be more suitable than hard gigging. Makes a big difference when done right, but at the same time can be in need of regular adjustment.

Cheers,
Janne

Try couple of different felt thicknesses for those keys if the regular size isn't thick enough. My suggestion is to buy something like this:

http://cdn1.bigcommerce.com/n-ww20x/sramxo/products/738/images/2843/Key_Bushing_Tip_Burning_Blade__74824.1385738153.1280.1280.JPG?c=2

and use temperature adjustable soldering iron (or just switch on/off all the time) to get those old ones off. Then you need a lot of clamps to hold the new felts in place while the glue dryes.

And for the white key caps...that's even more work. The caps of the -79 piano should come off pretty easily with a sharp knife. Glueing new ones is fast, but then you need to file the sides (straight!) by hand. New caps are never exactly same size with your keys.

It's a lot of work, been there done that. If you are restoring it for resale, too much work, imho. If you're restoring it for yourself and have time to spend, then go for it!

That dyno-my-piano proto was based on this one:

http://www.lynx.net/~jc/DMP900components-Schem.jpg


And yes, it's impossible to determine which is "the best rhodes preamp", it's a matter of personal preference. Instead we could provide info/audio on different type of preamps and that way we all could benefit on the journey to find the best rhodes sound for ourselves.

I made a proto of the dyno-my-piano preamp based on a schematic found on the forums. The eq curve is quite different compared to the peterson, but the output signal level is very very low. Here's a video, this rhodes is a mk2 5280:

https://www.youtube.com/watch?v=Cf-HroHJsQo

I've also used the BBE Sonic Stomp pedal with Vintage Vibe stereo vibe preamp on my Rhodes 54.

Just sharing these for comparision. It's still a work-in-progress.

I just resoldered the pots of an old peterson preamp, now works like a charm! Cold solder joints is the first suspect, try it before you go changing the components. It is the easiest fix, particularly if you don't know much about electronics.

Big thumbs up!! 

Hi there! There's a lot of info on how to restore the Mark I lid, but have anyone got good diy results with the mark II lid? Mine is in a horrible condition. Any tips on sanding the groove-patterns in the lid? Is there a suitable "putty" for the plastic lid? Thanks!

Short video: https://drive.google.com/file/d/0B7eVQr1jQ_seTXQtUUJBTFRBR3c/view?usp=sharing

Cheers,
Janne

Nice Job! I'm planning to do something similar, so this has been very interesting to follow!

I'd borrow one of those VV powers before buying and test the preamp. If it didn't work, you could get a discount and fixing the preamp is pretty easy if you know anything about electronics.

Thanks, have to try that. I saw you doing it like that on your video..

That cheap tachometer actually worked fine even faster rate than in that video. My biggest concern was how steadily the big heavy reel would spin (but it did!) and that's why I was taking it slowly.

The reason why I posted the video was to show that fixing a dead rhodes pickup with a brand new wire (AWG38) is pretty easy! Using the same wire is more problematic, mostly because it tends to break when rewinding. Instant Game Over.

1 more mic broke when I soldered them back. The caution about removing the mics is well justified, but if you are willing to learn how to rewind the broken mics, go for it! For rewinding I used 38AWG copper wire, reel mounted on a steady steel pole, a cordless drill with the mic mounted on a wood stick and a tachometer. It took 20-30min per mic (i was going slow just in case..). It's really not "rocket science", you just need those basic tools and _patience_. If you'd like to rewind the SAME OLD wire, then you'll need to mount the pickup to a very smoothly rotating surface, otherwise the old copper wire will break. I wasn't able to do that, but I didn't need to, because of the new wire that I was using.

A short video of my setup:

https://www.youtube.com/watch?v=bv1raPnFmvg

Cheers,
Janne

Here's a pic from my project. I used dremel and scotch brite wheels to clean the tines. Good luck with those, I'd be interesting to hear if you got those cleaned and working!

I removed all the pickup wiring (73 Mark II (5280) with white tape pickups) and 12 of the 73 didn't make it. They varied between 180 to 214ohms. 

Thanks David!

So, the tape is there just to keep the dirt out and protect the wiring? And yes, I know that removing the pickup bus wiring can damage the pickups. The Rhodes that I'm currently restoring has been out of its (lower) case for many years and literally everything is covered with dirt. I won't look new if I'll leave the pickup tapes the way they are. I even took the tone bars and the harp metal frame to be re-zinced.

Did anyone find a suitable clear or white tape? Or can I use just any tape? I guess it's 1/2" wide?

My mark II 73 has white tape on the pickups, but they are complitely covered with dirt and I would like to have then cleaned, preferable changed to clear tape. The whole harp is going to be renewed, and those ugly dirty white tapes can't stay Any ideas?

Thanks! My plan is to make this piano a stage model with vv stereo vib preamp. Now I'm working on the harp and the keys. If all goes well I will finish the case with new tolex and hardware, add stage legs and pedal (from VV).

BTW, the first try of my case were little too shallow when I put the mechanics inside and tried to close the top case. It fit without the lid, but with the lid it didn't. My mistake was to use 15mm plywood instead of 12mm (sorry metric:)). The 3mm difference actually made the case to shallow for the piano, so there really isn't much room inside the case. You can try this by putting something on top of your lid and try to close the top case. Well, at least this was my experience. Try it before cutting the pieces, especially if you do it without power tools! ;-)

A little background info... My brother owns a company that manufactures professional PA loudspeakers ( www.auraaudio.fi ), so my "case building" is more like him pressing the buttons of this huge industrial type of machine (error tolerance below 0,1mm), than me actually using a hand-saw. I only worried about the measurements, glued and nail gunned the whole thing.

Hat's off to those who will try to build the case without very good power tools. I wouldn't try it myself.

-Janne

Sweet! Thank you! 

Hi guys. I just finished building a case for my stage/suitcase (don't know which it is since theres no electronics or case) using measurements from David's 3D sketches and some other. Here is some pics.


Cheers,
Janne

Thanks! I'm pretty happy with the tolex, my first try! Next thing would be to doing something for the lid. Shiny white would be nice. I think I'm going to leave the paint job for the professional and not trying to do that myself. Black would be easier, I think..

All done!

I actually put these to my rhodes 54 (with the back check kit). I haven't decided yet whether I'll keep them or loose them. They feel little faster now, but the stop position feels little bouncy.

Yes, original pieces. Only tool was this:

http://static1.motonet.fi/img/6/601202/500/601202.jpg

It came off quite easily, you could even get job done only by hand. If someone have retolexed the case using super glue etc it's going to be a diffrent story..