Dyno preamp copy

Started by Marc-Etienne HUNEAU, May 27, 2007, 11:23:48 AM

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Marc-Etienne HUNEAU

Hi gang,

I'm not talking about a new version/copy, I'm talking about a PCB my brother-in-law designed from the by-hand schematics I found somewhere.

I don't remember who did this, but he's a techie who happened to have a Dyno-Rhodes in front of him and he copied the circuit.

Anyway, we have a first version of the PCB, I'm gonna build a prototype.

I'll keep this thread posted with the results.

Rob A

Sounds like a worthwhile project--I'll follow with interest.

Pale

I have already made a working  dyno clone preamp, search the forum for more information, I have already  posted some pictures and clips.
'80. Stage 73 Mk II

Marc-Etienne HUNEAU

Well, great minds...

Great job, I like the box, and very nice playing and clips.

So, I don't think you answered : did you copy the preamp from the "german schematics" ?

I love your phaser, do you have a PCB/Layout ?

Damn, I think I'm getting more pleasure from tweaking the rhodes and getting that perfect sound than by actually playing it.

Pale

Actually, a lot has happened since I posted the clips: I have a new, custom namerail,made just for my PCB. I have started selling my own custom preamp, dyno preamp and phaser on the same PCB, better pots, custom namerail, filtered power supply ( no hum! ), etc!

I have also found that schematic on that german site, but I also have my own schematic, reverse engineered from an original dyno preamp. I have made a few minor tweaks , mostly because I had to replace the old FETs with the new ones since the old ones are not in production anymore ( or I just couldn't find them ).

The phaser is a MXR 45 clone, great subtle, creamy phaser ( it's less subtle in my own board cos I tweaked it that way, but it's very subtle on another board I've made for one customer ).


Here's a picture of the whole thing, mounted... sorry about the quality, it was taken with a mobile phone. That's not actually my Rhodes, mine has exactly the same namerail,but with black knobs.

'80. Stage 73 Mk II

Marc-Etienne HUNEAU

Tell us more : what's the price ? :-)

Pale

Quote from: "Marc-Etienne HUNEAU"Tell us more : what's the price ? :-)

We can discuss the price over PM if you are interested. :D The biggest factor in the price are my work hours since it's all hand made, but the price is affordable.
By removing some of the features I can cut the price down, like selling it with no namerail, or no pots+knobs, just the dyno without phaser or vice versa etc. I can basically just send you the PCB,and if you happen to have double pots you can solder them yourself and mount the dyno preamp in your original namerail
( unfortunately,the phaser option adds another pot so you can't mount it in original namerail even with double pots ).
'80. Stage 73 Mk II

Marc-Etienne HUNEAU

In fact, since I already have my dyno clone (have yet to build it), I'm especially interested in the phaser... The Dyno will be installed outside, I guess. In a stand alone box.

Maybe with your phaser board too. :-)

Pale

Quote from: "Marc-Etienne HUNEAU"In fact, since I already have my dyno clone (have yet to build it), I'm especially interested in the phaser... The Dyno will be installed outside, I guess. In a stand alone box.

Maybe with your phaser board too. :-)

That was the way I intended it to be in the first place! My original idea was to make a wooden box with several effects: phaser, chorus, tremolo, envelope filter, overdrive,dyno and to keep it on top of the  Rhodes. A nice wooden box with lots of knobs on top side :D But Since I sometimes keep a second board on my Mark II that box would be a bit impractical, so I decided to install the dyno+phaser inside the Rhodes.
'80. Stage 73 Mk II

jazzguitarboy

I just built a copy of the Dyno preamp using the schematic that's available online at http://www.tasteundtechnik.de/bilder/dyno_pro_pre.jpg and it sounds spectacular!  I built it on perfboard with random parts from the EE labs at my school and put it in a Radio Shack enclosure.

I have a 1978 MkI Stage 73.  Prior to building the preamp, I had installed new grommets, Teflon-sprayed the felts, and adjusted the strikeline, escapement, and pickup placement.  I haven't had to change any of these adjustments since I started using the preamp.

With the Overtone knob above 12:00, I can get that exaggerated bell-like Dyno sound, but I can also dial in a more mellow tone or a more bark-like attack if I want it.  It sounds really good through a chorus pedal.  I still like the sound just a little bit better through my Dumble Overdrive Reverb clone (50w tube head) and a 2x12 cab - it's warmer and beefier.

I'll post clips soon.

joseph

jazzguitarboy, that's great!
how much did it cost you, all in all, and how long did it take you?

jazzguitarboy

Not much - I was able to get most of the parts from school - I'm an electrical engineering student.  If you order everything from Mouser, shouldn't be more than $30 in parts.  The most expensive parts will be the enclosure, the pots, and the knobs - the rest is cheap.

Build took about 2 hours - I laid it out on perfboard just like it looks on the schematic, and routed wires to the pots on the front panel of the box.

I would recommend building it inside a metal enclosure.  I built it in a plastic box, but it picks up noise pretty easily.

4kinga

Hey jazzguitarboy (jgb?),
If you don't mind:

What did you use for transistors? The bf245 or something else?
Whats your signal path?
harp->dyno pre->amp?
Are you using a wall-wart for power?

I'm thinking of building one of these and would love some input before I start.

Thanks.

Chris Carroll

A while ago we  have drawn and made available for anyone a free schematic of the original Dyno my Piano "Pro Piano Mod"  to copy. We also sell the completed board on our website if anyone is interested. it comes with battery option as well as power wart.  It is the  best replica around without having dual concentric pots. www.vintagevibe.com
Vintage Vibe will do all we can to help anyone out in a fair and honest way. Call us up or email anytime.  "Love is the answer"

Pale

Quote from: "Quadrapuss"It is the  best replica around without having dual concentric pots. www.vintagevibe.com

Dual concetric pots or single pots are just the same. Dual ones are just more practical if you want to mount your preamp into existing namerail.
'80. Stage 73 Mk II

Marc-Etienne HUNEAU

I know it's been a long time since I originated this project... but I have tested my Dyno Preamp today.

It's good. I have to complete the assembly, put the PCB neatly into the box (I might put the preamp into the piano later if I can find concentric 10K pots), shield the thing and replace my quick and dirty wiring with shielded coax wire.... but my first tests are... pleasing to the ears !

Now, simple question for the electronics gurus here : how does it work ? I mean the fundamental/overtone part ?

Pale

Quote from: "Marc-Etienne HUNEAU"I know it's been a long time since I originated this project... but I have tested my Dyno Preamp today.

It's good. I have to complete the assembly, put the PCB neatly into the box (I might put the preamp into the piano later if I can find concentric 10K pots), shield the thing and replace my quick and dirty wiring with shielded coax wire.... but my first tests are... pleasing to the ears !

Now, simple question for the electronics gurus here : how does it work ? I mean the fundamental/overtone part ?

It divides the input signal ( form your harp ) into 3 different amplifiers/filters, each one for different range ( bass, normal or fundamental, overtone ). Then you have an exit amp summing up all those 3 signals into one exit signal ( volume pot ).

Basically, your input signal goes into 3 ways, and with each filter/amp you amplify a specific part of spectrum thus changing the sound.

That's a simple explanation, real explanation of physics and electronics behind this preamp would be much more complicated and would require a university degree in el. engineering.
'80. Stage 73 Mk II

Marc-Etienne HUNEAU


Tehu

Hi! Yesterday my brother and I begin a DIY Project, the DPM900 ''ProEQ''.
We follow the Schematic on the German site and it works well!






The Next Step is a ''namePlate'' for the ''overtone'' and ''normal'' Knob!
And we'll add some effect like : Phase 90, Chorus, Tremolo

PS: Whats the best chorus for a rhodes?

Thanks
Xavier
Rhodes Mark 1 Suitcase 88 1977, Wurlitzer 200a, Columbia Elepian 713, Yamaha CP60M, Hohner Clavinet D6, Baldwin CW-8-S, Roland VK9, Roland RS101, Roland SH1000, Teisco S100P, Yamaha SK15, Siel Orchestra 1, Sequential Six Ttak, Sequential Prophet 2002, Behringer VC340, Behringer MS101, MPC2000XL, Roland SBF325, Roland RE-201, Roland MPA100, Leslie 710

The Real MC

Best chorus is Boss chorus or dc-3.  It's also hard to beat a real Leslie speaker.  Lately I've been using Korg SDD-1200 which can be set up for stereo chorusing, great box and can be found cheap.

DynoCzarus Rex

That Eighties Rack Chorus would also be a great choice as well. It's basically a clone the dyno my tri-stereo chorus made by fulltone
http://www.fulltone.com/products/80s-rack-chorus
Rhodes Mark I 73 key Suitcase Model (1978)
Fender Rhodes 88 key Stage Model (1973) with 1982 Dyno-My-Piano Pro EQ
Rhodie Preamp
KMD Flanger
Boss CE-2 (1982)
Amdek CHK-100 Chorus
MXR Phase 90 1974 Script Logo Reissue
MXR Phase 100 (1978)
Dave Smith Instruments Prophet 08
Korg MS-20 Mini
Yamaha MG10XU

Tehu

Thanks, I now use a nice Ibanez UE-405 with a true steroe analog chorus, make my rhodes sound like heaven!
Rhodes Mark 1 Suitcase 88 1977, Wurlitzer 200a, Columbia Elepian 713, Yamaha CP60M, Hohner Clavinet D6, Baldwin CW-8-S, Roland VK9, Roland RS101, Roland SH1000, Teisco S100P, Yamaha SK15, Siel Orchestra 1, Sequential Six Ttak, Sequential Prophet 2002, Behringer VC340, Behringer MS101, MPC2000XL, Roland SBF325, Roland RE-201, Roland MPA100, Leslie 710