Hammond H-112 Percussion Mod

[sread]

I've heard of mod you can do to the percussion on a H-112 to get a more b3 type sound. Just curious to see if anyone has done this and possibly how....

[indianajo]

All the overtones are available to the mixer/percussion chassis. Just the market dictated Hammond make banjo & guitar out of them instead of two's and three's. Two's and three's are actual pure overtones available to the connector on the mixer/p chassis. You just have to sacrifice a banjo tab and delete the non three overtones, or guitar to delete the non two overtones. I'm replacing my mixer with op amps because of the ****y tube sockets, so rewiring behind that is not my highest priority. The H already has one key percussion like the B3, or every key percussion on the top manual, which I personally find way cooler than the B3 style. Just flip the touch control tab one way or the other,
Also geoelectro says H's don't have enough busbar cross talk to emulate A/B/C, so adding crosstalk with capacitors or resistors is way easier than taking it out of a B or C. I'm also holding off on that until I score all the $2 relays in the world, before I tell you how to do it. I'm going to put the cross talk on relays, because B/C crosstalk sounds stupid on classical music. That is how Conn sold so many organs to classical people with their ****y plastic bus bars and switches. Conn had a better classical sound. I'm the one weird person on here that like both Buxtehuda at Leipzig, and Greg Allman at Muscle Shoals. And I don't want to buy a chi**** computer to do it with.
The H100 schematic is on archive.org (the service manual) and also at captain-foldback.com. The first are fuzzy and the second is cut up into slices, so it takes both to be able to read them.

[sread]

I will gladly sacrafice the banjo tab to get more chif and spit. Would love to know how to do it.

btw - I agree, it would be nice to have the best of both worlds in an organ (classical and rock / jazz). It just seems that the H-112 leans more toward the ornate / conventional side.

[T-200]

Hi Sread,

Check these pages: http://www.keyboardpartner.de/hammon...ifications.htm
There are schematics of the H with some mods in the filters and some help to change the percussion. It's not finished info, but there may be something to help you out...

Jussi

[indianajo]

B3 percussion on H100

So both "guitar" percussion tab, and "banjo" percussion tab have both 2nd and 3rd harmonic. Cut all off but second harmonic on guitar tab. Cut all off but third harmonic on banjo tab. Voila! B3 percussion. Tape up the ones you are not using with electrical tape so they don't short out. H***** F***** and lumberyard electrical tape fall off. Use Scotch 33 tape from the local electrical supply house or mcmaster.com. According to the keyboardpartner.de drawing, 2nd harmonic is yellow and 3rd harmonic is green. I can't confirm this from personal experience.
Note most H100' s are tinny and bassless because of the dried up electrolytic capacitors. My percussion didn't work at all, I had to read here how it was supposed to work. I thought "percussion" was some kind of drum machine, band people call the loud noise at the beginning of the note the "attack". I replaced 70 electronlytic caps and my bass will rattle the chandelier. My percussion didn't work at all until I replaced the fifth tall can cap, the one on the back of the percussion chassis on the back of the keyboard enclosure. Now my percussion can be turned up enough to be objectionable. If you're short money, do the 10 uf ones on the preamps first, they are not very expensive. The electrolytics are the tall aluminum cans, or the cans covered with plastic or cardboard, with a plus on one end or a minus on the other. I spent $200, but if you replace the tall cans with internal terminal strips and axial caps, you can save $120. I didn't replace the harp feature caps. As with any capacitor replacement, read aikenamps.com technical resources button, technician safety button, about not killing yourself. All metal should be measured under 25 VDC before you touch it, only with one hand. A/B/C's use paper (early) or film (late) capacitors where the H has electrolytic, so A/B/C's sound about like original but weak and feeble, made up by the Leslie, until the 2 electrolytic caps on the preamp short and burn up the rectifier tube or the power transformer.

[sread]

Wow. Sounds pretty easy. So it would seem that when you want the 3rd harmonic you select Guitar and when you want 2nd, you select Banjo? I'll give this a shot when I get home this weekend.

Next up I'll dive into replacing the caps. Where did you get yours?

btw Thanks for the info.

[indianajo]

After you cut off the other harmonics wires, both guitar and banjo have two (yellow) and three (green). You cut off all the other ones and tape them up. However, your percussion probably doesn't work at all. I think guitar and banjo sound the stupidest, but Brandon likes banjo on his T. I have a real banjo, I am a purist.
I bought my FP can caps from tubesandmore.com (AZ) and triodeelectronics.com (IL) but they are $30 each and a real ***** to get out with a 130 W iron, so I'm putting axial caps under the deck on terminal strips the next one. Axial 1000 hour 47 uf 450 VDC caps are 79k3643 from Newark.com. You use the selector chart to find the other values. Passive components, capacitors, aluminum electrolytic capacitors, then type in your value. 50, 40, 30, 20 are obsolete, they are now 22, 33,47 uf or you pay extra. I found some nice Panasonic 30 uf 450 V 2000 hour capacitors at mouser.com in TX last weekend $1.40 ea, and sometimes panasonic is made in USA. But mouser makes you download the datafile before you can find out the hours life, and putting in unrated garbage quality caps is a good way to do it again in 2 years. The terminal strips they mount on are PN P-0301H01, P-0501H05, P0600H, from tubesandmore.com or electronicsurplus.com other numbers, 5 for $1. The electrolytics at 10 uf 50 v and under, you can replace with film caps that last practically forever. There were some burnt 1 W resistors in the power amp chassis that would cut output power at 15% over nominal resistance, that I replaced. Make sure they are rated for 450 V, modern resistors are very short, too short in the 1/4 & 1/2 watt size for tube circuits.
Mark the plus on the PCB before you change them and make drawings or pictures before you start. I did them in this order - power chassis, power amp, mixer/pop filter/percussion (on the back of the keyboard enclosure) then the ones in the preamp boxes on the back of the keyboard, then the pedal ones and couplers under the chassis in the power amp. I bought $50 at a time, and newark loves me and replaces mis-shipped product for free.
Before touching any metal that might kill you with stored voltage, read aikenamps.com technical resources button, technician safety button, about simple rules to preserve your life. You've got to measure metal at under 25 VDC, or safely discharge it, and use 1 hand only in there until it is safe. No Jewelry. Safety glasses when unsoldering, solder splashes. A WP35 iron with a chisel tip is good enough to put them in, but it takes 130 W to get those twist tab cans off.

[ELPFan15]

I tried this, and I don't think it worked. I know my percussion worked before, and I'm debating giving up, and hooking the percussion up as it was originally. I cut all wires except green on the banjo tab, and all wires except green and yellow on the guitar tab(maybe that's why it's not working).

[indianajo]

Another satisfied customer! Not. I bought an A100 to see what twos and threes percussion actually sound like, but had to stop recap for summer. I might be some help in November after the rains start and I can't do real work.
Oh, do glock and marimba and all the other percussion switches you didn't mess with still work? Do they work with touch control on and off? With second voice on and off?
Were there two wires of the same color attached to some of the places you cut off? By which I mean the harmonic comes from the source, goes to the twos terminal on every one of 8 percussion switches, then out to the preamp connector? So if you cut two wires off a switch, you have to twist & solder them together in the air and insulate them to get the noise through to the amp? Maybe?
What is the date on the can cap on your perc amp/pedal amp on the back of the keyboard? tube or solid state? (two separate little transistor amps instead of one perc/pedal amp with tubes) . My percussion didn't work at all until I put that can cap on, about the fiftieth of my seventy. In fact I didn't know what percussion was until I got that cap renewed.
The solid state percussion amp bobmann sold me has tiny little tantalum electrolytic capacitors, I don't trust the old ones any farther than I can hit them with a ball bat. My 1968 organ had 4 tantalum electrolytic caps in the power amp, one was replaced in 70, one in 72, one in 73 by hammond dealer service. Both replacement tantalum caps I bought to put in my ST120 power amp were bad from the store, had a sizzling noise.

[T-200]

If you just cut the wires behind the percussion tabs in H or E series you also cut the signal going thru to the darwbars. You should connect the cut wires to the next tab wire of the same color to make sure that the signal goes on to the matching transformer and to the darwbars. It is not so simple :-(
There are some threads here that explain the procedure more detailed...

Jussi

[T-200]

What is a darwbar...?:embarrassed:

[jdoc]

don't know you waskle wabbit

[T-200]

...dawn...

[ELPFan15]

Another satisfied customer! Not. I bought an A100 to see what twos and threes percussion actually sound like, but had to stop recap for summer. I might be some help in November after the rains start and I can't do real work.
Oh, do glock and marimba and all the other percussion switches you didn't mess with still work? Do they work with touch control on and off? With second voice on and off?
Were there two wires of the same color attached to some of the places you cut off? By which I mean the harmonic comes from the source, goes to the twos terminal on every one of 8 percussion switches, then out to the preamp connector? So if you cut two wires off a switch, you have to twist & solder them together in the air and insulate them to get the noise through to the amp? Maybe?
What is the date on the can cap on your perc amp/pedal amp on the back of the keyboard? tube or solid state? (two separate little transistor amps instead of one perc/pedal amp with tubes) . My percussion didn't work at all until I put that can cap on, about the fiftieth of my seventy. In fact I didn't know what percussion was until I got that cap renewed.
The solid state percussion amp bobmann sold me has tiny little tantalum electrolytic capacitors, I don't trust the old ones any farther than I can hit them with a ball bat. My 1968 organ had 4 tantalum electrolytic caps in the power amp, one was replaced in 70, one in 72, one in 73 by hammond dealer service. Both replacement tantalum caps I bought to put in my ST120 power amp were bad from the store, had a sizzling noise.

Only the chime and glock work now, the guitar only works with second voice or touch control on. It's a solid state percussion amp, I'll have to open it up for the specifics.

[indianajo]

If you found two wires of the same color on either of the tabs that you cut off, you have to splice the two wires together and insulate them. I would use solder and a twist of wire, and some scotch 33 electrical tape (HF electrical tape doesn't stay stuck). As T200 said , the overtones are daisychained through the tab switches. I should have thought of that, sorry.
I bought some 1 mf, some 6.8 mf and some bigger electrolytics for my SS percussion amp, I think they were 47 mf or something. I bought ceramic dielectric +-10% caps for the 1 and 6.8, no sense buying tantalum caps that wear out in 10-20 years all over again. I think the red end of the tantalums is plus. I haven't installed caps yet , I have to trace the H100 connector and make sure they don't use the pin that the 400 V comes in on the tube amp for something else, before I install that chassis.