Errata: Deadringer ver.1 wiring

[madbean]

As promised, here is fix for ver.1 of the Deadringer. When I constructed the original schematic, I inadvertently reversed the order of some things, and had at least one portion routed incorrectly. Additionally, there were three incorrect values listed. My apologies for these errors. I was too hasty in releasing it, and while I thought I had worked it out correctly (I did prototype the build, of course) it appears I wasn't paying enough attention.

The value corrections are as follows:

C9 = 10n (orig. 1n)
C4 = 51pF (orig. 100pF)
R15  = 150k (orig. 510k)

Of these three value changes, C9 is the most critical. If you have a ver.1 board, you can probably get away with only changing this value. But, you can change all three, too, if you want to take the time.

Following is a diagram that I believe corrects the wiring situation. My test results with the version 1 build seem to confirm this. The Flat Mids mode is subtle, however this is due to having the incorrect value for C9 (it shold be 10n, not 1n) on my build. When placing another higher valued cap along with C9, the change was much more pronounced.

A brief explanation of how all these clipping choices work: the mos/sil switch (SPDT) does exactly as it indicates. It changes between the Mosfet and Silicon diode clipping in the feedback loop of the opamp. The top position of the 3-way DPDT lets you select compression cut, flat mids and vintage mode. In CC mode, the diodes are actually disconnected, meaning that clipping comes directly via the opamp - not the diodes. This is a much harsher type of clipping, although it can sound very open when the gain is dialed back.

In FM mode, C9 and R13 are placed in parallel with the tone control, thereby altering the frequency roll-off point. It essentially serves to counteract the tone control to make it less severe. Finally, in VIN mode, you have the traditional clipping of a gerenic TS: diode clipping, and the regular active first order tone control.

The Boost mode simply puts a 1M variable resistor in series with the drive control, thereby increasing the overall gain and 'scorching' the diodes a bit more. It has the most impact when the drive control is around half-way or less - this is where you will find the biggest difference in the added gain. In this sense, it's not a boost at all, but rather a "more" option.

On the wiring diagram, you will need to connect the S1, S2 and S4 pads to an On-On-On dpdt (available from smallbear) and run one additional wire from the DPDT to the 3PDT used for the 'boost' option. This should correct the previous wiring/routing errors. S3 should not be connected to anything.

One additional note: looking at a few pics of the insides of the latest FD-2 version, I noticed there is a small change with the clipping setup. It looks like Fuller altered the back-to-back 1N4005/1n914 diodes. The newest change appears to be swapping the 1n914 for two 1n4005 in series. So, following the Deadringer schematic, you would leave D1 the same, but in place of D2 you would solder two more 1n4005's in series. This preserves the asymmetrical type clipping of the previous version, but increases the overall forward voltage with the two new diodes in series. Hence, his description of a more 'open' sound. So, this is technically an additional correction to both ver.1 AND ver.2 of the Deadringer.

Sorry for the long winded post - I thought some of this additional info might shed some light on the design of the pedal. Diagram is attached below.

[attachment deleted by admin]

[giudis]

instead of D1=1n4005 can I use a 1n4007?


thanks so much brian!

[madbean]

Yes, you sure can.

[Neeno]

Hi guys !
My first post here... long time Diy'er...
The Deadringer is my 7th stompbox build and I really love it.
I used madbean's single sided PCB layout and etched it myself, followed the actual BOM and the wiring diagram, which I can confirm is perfectly working.

Actually with the 1N914 in parallel with a 1N4005 the "Standard" mode (or silicon) is lower in volume compared to the "Mosfet" mode.

I think this is due to the symmetrical vs. asymmetrical clipping happening. (I did a similar mod on my TS)
Using two 1n4005 in series to replace the 1n914 makes the "Standard" and the "Mosfet" mode equal in volume, exactly like the current Fulldrive 2.

Thank you for this thread Madbean, and for all the great projects !

Neeno

As promised, here is fix for ver.1 of the Deadringer. When I constructed the original schematic, I inadvertently reversed the order of some things, and had at least one portion routed incorrectly. Additionally, there were three incorrect values listed. My apologies for these errors. I was too hasty in releasing it, and while I thought I had worked it out correctly (I did prototype the build, of course) it appears I wasn't paying enough attention.

The value corrections are as follows:

C9 = 10n (orig. 1n)
C4 = 51pF (orig. 100pF)
R15  = 150k (orig. 510k)

Of these three value changes, C9 is the most critical. If you have a ver.1 board, you can probably get away with only changing this value. But, you can change all three, too, if you want to take the time.

Following is a diagram that I believe corrects the wiring situation. My test results with the version 1 build seem to confirm this. The Flat Mids mode is subtle, however this is due to having the incorrect value for C9 (it shold be 10n, not 1n) on my build. When placing another higher valued cap along with C9, the change was much more pronounced.

A brief explanation of how all these clipping choices work: the mos/sil switch (SPDT) does exactly as it indicates. It changes between the Mosfet and Silicon diode clipping in the feedback loop of the opamp. The top position of the 3-way DPDT lets you select compression cut, flat mids and vintage mode. In CC mode, the diodes are actually disconnected, meaning that clipping comes directly via the opamp - not the diodes. This is a much harsher type of clipping, although it can sound very open when the gain is dialed back.

In FM mode, C9 and R13 are placed in parallel with the tone control, thereby altering the frequency roll-off point. It essentially serves to counteract the tone control to make it less severe. Finally, in VIN mode, you have the traditional clipping of a gerenic TS: diode clipping, and the regular active first order tone control.

The Boost mode simply puts a 1M variable resistor in series with the drive control, thereby increasing the overall gain and 'scorching' the diodes a bit more. It has the most impact when the drive control is around half-way or less - this is where you will find the biggest difference in the added gain. In this sense, it's not a boost at all, but rather a "more" option.

On the wiring diagram, you will need to connect the S1, S2 and S4 pads to an On-On-On dpdt (available from smallbear) and run one additional wire from the DPDT to the 3PDT used for the 'boost' option. This should correct the previous wiring/routing errors. S3 should not be connected to anything.

One additional note: looking at a few pics of the insides of the latest FD-2 version, I noticed there is a small change with the clipping setup. It looks like Fuller altered the back-to-back 1N4005/1n914 diodes. The newest change appears to be swapping the 1n914 for two 1n4005 in series. So, following the Deadringer schematic, you would leave D1 the same, but in place of D2 you would solder two more 1n4005's in series. This preserves the asymmetrical type clipping of the previous version, but increases the overall forward voltage with the two new diodes in series. Hence, his description of a more 'open' sound. So, this is technically an additional correction to both ver.1 AND ver.2 of the Deadringer.

Sorry for the long winded post - I thought some of this additional info might shed some light on the design of the pedal. Diagram is attached below.

[giudis]

Hi Brian,
excuse me, I am making the Deadringer and I'd like to know if this part of your post had be corrected on actual pdf project, or better, do you advise this change?:
"One additional note: looking at a few pics of the insides of the latest FD-2 version, I noticed there is a small change with the clipping setup. It looks like Fuller altered the back-to-back 1N4005/1n914 diodes. The newest change appears to be swapping the 1n914 for two 1n4005 in series. So, following the Deadringer schematic, you would leave D1 the same, but in place of D2 you would solder two more 1n4005's in series. This preserves the asymmetrical type clipping of the previous version, but increases the overall forward voltage with the two new diodes in series. Hence, his description of a more 'open' sound. So, this is technically an additional correction to both ver.1 AND ver.2 of the Deadringer."

and the new attached wiring schematics works only for the single sided version or for fabbed too?

last question: the on-on-on switch order is CC - FV - V for fabbed version too?

thanks so much, have a nice week!

....and welcome to neeno!!

[madbean]

The wiring diagram above is only for version 1 of the Deadringer only. It is a correction for the first few batch of boards I made of this project in June 2010.

The correct wiring diagrams for the single and double sided version are in the project documentation on the Projects page.

[ichilton]

One additional note: looking at a few pics of the insides of the latest FD-2 version, I noticed there is a small change with the clipping setup. It looks like Fuller altered the back-to-back 1N4005/1n914 diodes. The newest change appears to be swapping the 1n914 for two 1n4005 in series. So, following the Deadringer schematic, you would leave D1 the same, but in place of D2 you would solder two more 1n4005's in series. This preserves the asymmetrical type clipping of the previous version, but increases the overall forward voltage with the two new diodes in series. Hence, his description of a more 'open' sound. So, this is technically an additional correction to both ver.1 AND ver.2 of the Deadringer.

That's interesting!

Ian

[ichilton]

I found a good photo online:
http://solderman.fatabur.se/FD2/FD2_inside.jpg

It looks like C6 on the DeadRinger has changed from 100nF to 47nf (as per a Tubescreamer) - C7 on the photo (bottom middle).

You can also see the following (component labels refer to the photo, not the Deadringer):

- If you look on the left there, you can see D1 and D2 in series, then D6 going the other way, as madbean mentioned above. Then there is D10 which I assume is the 1N34A.

- Not sure what D9 is, just under that? - it looks like a resistor with only one band? - but it looks like it goes between the 2N7000's.

- In the top middle, there are 2 more 1N400x diodes - a different way of doing polarity protection instead of D3 on the DeadRinger maybe?

- Looking at the right hand side of the photo, there are 3x transistor packages, so there is now a Q5 (there was only 4 in the DeadRinger) - and another diode, D7 (there was only 4 in the DeadRinger)

Not sure what they are or where they go!

- The 220nF's (assume the value hasn't changed) connected to the tone pot (3rd along in the photo) have been changed to tantalum's.

Ian

[madbean]

You are right about that 100n - 47n change (C6 on the Deadringer). I prefer 100n there (also in a TS) but you can certainly change it to 47n. It will move the clipping frequency to be centered around 720Hz rather than 338Hz.

The two diodes in series was mentioned in this thread already - you can put two of either 1N4005 in series to get the same results (plus switch the other diode from 1n914 to 1N4005).

The one band resistor is 0 Ohm - it's just a jumper for the PCB.

The two diodes at the top are polarity protection - probably a 1N5817 in series with the 9v supply and then a 1N4001 right after that to ground. It's a bit more robust way of ensuring that reverse polarity will not damage any components. It does not have anything to do with the actual tone, though.

The transistors on the right are for the LED, I'm almost positive. They are probably some kind of 'millenium bypass' type set-up. He may have chosen that to ensure a more silent switching on the 3PDT. He did the same thing on the OCD, IIRC.

You can use tantalums for the tone section, of course. How much difference that makes over film I cannot say. Maybe some to one set of ears and none to another set. In any case, just make sure you put the negative side toward ground if you use tants.

[ichilton]

Hi Brian,

Thank you for looking into that!

So based on what you've said, changing C6 (to a 47nF) and D2 (to 2x 1N4005) should make a DeadRinger sound just like the new sparkle blue Mosfet model? - the other changes are just auxiliary and you can't see anything else that looks different from the photos?

(Everyone reports the new one to sound much brighter than the old ones - would those two changes account for that do you think?)

As an aside, is the DeadRinger based upon one of the early "10th Anniversary Mosfet" edition? (red coloured??).

Did you build it from a real pedal, or find a schematic? make any changes of your own?

Thanks,

Ian

[madbean]

Ian,

I don't know if it will make it sound exactly like the sparkle blue, but it will have all the same values, so it's a good guess that it will be very close. The Deadringer did not come directly from any one traced pedal but was put together from a consensus of existing schematics. There have not only been a few versions of the FD-2 over the years but small tweaks to values, as well. So, the DR is what I saw as the best approximation. I don't know enough about every version of the FD2 to say definitively that is a red 10th anniv or blue sparkle, etc. But, making the changes I suggested in the previous post should get you 99% there to the blue sparkle pic you posted. I guess it depends on how far you want to go with making an exact clone (using the same component types, brands, etc).

[ichilton]

Thanks for that.

You don't still have the schematics you worked from stashed away do you? - i'd be very interested in seeing them.

I've not been able to find any others with the Mosfet mode other than the DeadRinger, so would be particularly interested in finding out if you have one with that part on!

Thanks,

Ian

[madbean]

I don't have any other schem showing showing the mosfet part. The mosfet part was put in by me based on how I know it's supposed to work and from the gutshot I saw. Maybe someone else has drawn up or traced another FD2 by now, but perhaps not. Sorry I can;t be of more help with that.

[ichilton]

Ah, ok - do you have any of the schematics / gunshots you used stashed away still?

Did you compare it to a real one back then, or just work from the photos/schematics?

Thanks,

Ian

[ichilton]

Also... i've seen mention of the original using all linear pots - but you are using log for the vol & drive.

Did the real ones change in the later versions, or was that a change you made?

Thanks,

Ian