anderton ring mod..... insane

[marrstians]

i built the anderton ring mod from the epfm and it seems to be a bit crazy... beyond what it should be... it is always self oscilating louder than the guitar input and i can't figure out how to tame it... any suggestions...

it's the one with the 565 chip...

[Jason M.]

Does it help when you adjust R7 (2.5k null trimpot)?

This trimpot nulls out the carrier when you are not playing and it is VERY sensitive, but you should be able to almost completely get rid of the carrier feedthrough. Mark Hammer wisely suggested to make this a multi-turn trimpot instead of the single-turn type.

EPFM lists a couple of things to check in the case of excessive carrier feedthrough.

Good luck.

J.

[ExpAnonColin]

This trimpot nulls out the carrier when you are not playing and it is VERY sensitive, but you should be able to almost completely get rid of the carrier feedthrough.

+1

My guess at the problem as well.

-Colin

[marrstians]

i think i might have an older book than most others have... in my book it's project 9 and it said that my r1 is my null control... adjusting r7 just seemed to change pitch and not much else... i've heard that there was an updated version of the circuit but i'm not sure if i have the same one most people have...

[Jason M.]

Sounds like you have the first version of EPFM.
Sorry, I'm not familiar with that version's projects. I understand that many of them had revisions in the second edition.

[Thomas P.]

May it be possible for one of you to get me a scan of this ring modulator project? For educational purpose, you know...

[petemoore]

A killer Ring Mod schematic would go right onto a board...
 No biggie...tuff to talk about ckts we can't see...
 I would probably appreciate the CA writings more, if I could get my hands on some...lol...forgettaboudit///
 Gonna go dig out my three years of Guitar Player subscriptions from the early 70's...I'm  sure there were some schems in them.

[swt]

hey Guys!. I have the book, and built one. The carrier is never completely eliminated. It's pretty good ckt. I'd also like to get it working properly. Anyone knows of a good ring ckt to build?. Thanks.

[Zero the hero]

I've almost finished a maestro ring modulator, seems five times more difficult to set cause there are 5 trimpots to tune.

[Thomas P.]

I've almost finished a maestro ring modulator, seems five times more difficult to set cause there are 5 trimpots to tune.

You did what :?:  :?:  :?:
I've ever thought there were some obsolete IC stuff in it? Would it be possible to see a scan of the board?

[Dan N]

JC at viva analog has some thoughts and mods for the CA modulator:
http://www.lynx.bc.ca/~jc/pedals.html
(way over on the right)

[Zero the hero]

I've almost finished a maestro ring modulator, seems five times more difficult to set cause there are 5 trimpots to tune.

You did what :?:  :?:  :?:
I've ever thought there were some obsolete IC stuff in it? Would it be possible to see a scan of the board?

Eheheheheheheh.... veeeeeery sooooooooon!!!!! I used the original MC1495... I've promised that I would have posted this project (schem, PCB & layout) as soon as I'll have tested it carefully.

[Thomas P.]

Hey Zero!

How much did you pay for the MC1495??? And of course where did you buy it :wink:

I found it here in germany for 30€ which is far out, you know! I mean this is double the price of an MN3007 which I thought is the hottest one :wink:

[LP Hovercraft]

Are you powering it off of 2-9 volt batteries?  The null frequency comes out on mine when one battery is older and gives a higher voltage than the other.

[LP Hovercraft]

Duhhh..   The older battery gives off less voltage rather :oops:

[Zero the hero]

Hey Zero!

How much did you pay for the MC1495??? And of course where did you buy it :wink:

I found it here in germany for 30â,¬ which is far out, you know! I mean this is double the price of an MN3007 which I thought is the hottest one :wink:

I've bought it for 10 euros in a small shop in Milan. I suppose it was the last piece...
Tomorrw I'll write something else about it, I promise.

[Paul Perry (Frostwave)]

I designed a commercial ring modulator around a MC1495 years ago (when I was just starting out!) and of course the 1495 immediately went out of production
So my advice is to use an AD633 as a basis (the AD633 application notes are pretty clear).
And, if you are on a budget & try doig it with a CA3080 or other OTA based multiplier configuration, note that as the battery voltage changes, you are going to have to null out the carrier again.

[marrstians]

does anybody have the newer schem of the ring mod available... i think the old book has too many bugs that were later worked out....?

[Thomas P.]

I designed a commercial ring modulator around a MC1495 years ago (when I was just starting out!) and of course the 1495 immediately went out of production
So my advice is to use an AD633 as a basis (the AD633 application notes are pretty clear).
And, if you are on a budget & try doig it with a CA3080 or other OTA based multiplier configuration, note that as the battery voltage changes, you are going to have to null out the carrier again.

As I searched yesterday I found several stuff useing a MC1496 (which I can get really cheap :wink: ). Do you have any advice useing this one?
This would be a really great thing!!!

I also tried stuff with the AD633 since my simulation software contains it as a model. But I don't really get the CA3080 thing...

Then it would be best not to power it up with battery, right?!

[Paul Perry (Frostwave)]

A MC1496 will work, plus it has the advantage that it is a multiple sourced chip still used in radio applications. From memory, the 1495 & 1496 are designed for different apps, the 1496 is guaranteed for AC signals not DC, but that isn't a problem for guitar fx applications. With a synth, where you might expect the ring mod to accept very slow varyig waveforms, there might be a problem. And the 1495 & 1496 arent anything like nearly equivalent, they are acually different.
To 'get' the 3080 thing, look at the LM13700 application notes, where they show how to make a multiplier. The ecret is that the "modulation" signal is not only used to control the gain of the OTA, but it is also subtracted from the utput. (this is the hard part.. realising that ALL the resistors are there for a reason!)