BJF - Mighty Red Distortion

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snail
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Post by snail »

No, I don't have the gut shots.

I was just wondering (and hoping BJF could answer this one) if the new Mighty Red distortion is a remake or inspired by the handmade Dyna Red distortion.
I heard some really good coments about the dyna, is it still being made?

Thank you

Snail

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BJF
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Post by BJF »

Hi,

Dyna Red is still being made. MRD is a different circuit targeting very easily played- heavily distorted-albeit without mid scoop of the 80's, not really the sound to convert a guitar to a drumkit but to allow perhaps legato- a fun tool to bring out the spandex.....

The biggest problem with a sound like that is to my ear the noiselevels while the sound as such can be achieved in multiple ways

You'd need something like an overdrive to goose DRD to those levels.

In short different circuits different targets

Have fun
BJ

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picassochild
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Post by picassochild »

I found one pic

Image

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Post by soulsonic »

Interesting choice of opamp.
After reading the datasheet, let's assume it has a JFET input buffer. That's about all I can say. It's fairly obvious that red LEDs are used for clipping somewhere in the circuit, but I cannot tell for sure whether it's in the feedback loop of the opamp or not; I'm guessing maybe they are.

So, Mad Professor stuff isn't gooped? If that's the case, I'm surprised more of them haven't been traced.
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bestegw
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Post by bestegw »

BJF wrote:You'd need something like an overdrive to goose DRD to those levels.
I've been reading Bjorn's posts for a while (thank you Bjorn!!) and he always seems to give away small hints as to what the base for his pedals is. So, with the above quote and a parts-count (5 trannies, an op-amp and red LED clippers) there's a pretty good chance that the Mighty Red Distortion is in fact an overdrive driving a transistor-based distortion, maybe with an in- and output buffer?

And if I'm all wrong (which wouldn't be the first time :D ) it'd still be a fun idea.

All the best!

BesteGW

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Post by bacaruda »

with the number of trannies I would also suspect a discrete opamp.

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Post by mdroberts1243 »

picassochild wrote:I found one pic
Does anybody recognize the box? Doesn't look like any of the standard ones... I'm interested in finding a box with straighter sides (if that is possible, given the die release requirements).

Thanks,
-mark.
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Post by celadine »

FWIW the AD797 is considered to be a premiere audio op amp. At 10$ a chip its expensive, not in 20$+ opa627 terrritory, or ???$ for a discrete op amp. Still, interesting to see Mr. BJF use it in a stompbox.

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Post by soulsonic »

mdroberts1243 wrote: Does anybody recognize the box? Doesn't look like any of the standard ones... I'm interested in finding a box with straighter sides (if that is possible, given the die release requirements).

Thanks,
From the BJFE Guitar Effects Community forum,
The box used for the standard models is an ELFA K-430 and is made by
Solna Pressgjuteri in Sweden
You can see the full interview here:
http://www.bjfe.org/viewtopic.php?f=3&t=648

Info about the boxes here:
http://www.elfaelektronika.lt/cgi-bin/i ... =50-001-04
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Post by sadrew »

snail wrote:No, I don't have the gut shots.



I was just wondering (and hoping BJF could answer this one) if the new Mighty Red distortion is a remake or inspired by the handmade Dyna Red distortion.

I heard some really good coments about the dyna, is it still being made?



Thank you



Snail

here is a demo video of the two pedals.

http://www.heggle.com/item/3629208/BJF_ ... onePostcom


sound very similar to my ears.

i tried a dyna red... very nice distortion and good at low gain settings too.

i'm looking for a schematic or good resolution pics for reversing it.

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Post by BJF »

Hi,

I did a demo video once- I have no idea when or even if it ever will be edited and shown, anyway I did then try to answer the question wether MRD and DRD would be similar or?

My conclusion as also the demovideo showed was that MRD would care a bit less what guitar would drive it but that it'd possibly be more my choice with low output pick ups such as a strat, while the DRD is more about a dynamic range and something I'd just therefore would enjoy more with humbuckers......

Nah, ofcourse those are not the same circuit........what would be the fun in that?

I'll say this AD797 was my choice for MRD for one parameter in particurlar- actually I'd care less what it costs as long as it does precisely what it is supposed to.......economic department may have a different view, but my targets would be sound and function.

I might also not encourage hoping for a wide dynamic range in the MRD, but then that was not the target for that design either.

Hm, I wonder I might make something dynamic for MP the next time :idea:

MP pedals are made very closely to the way BJF pedals are and yes the K-430 is expensive and heavy, costs more to ship but stays nicely on the floor .......

It's a fun challange to draw designs for large productions- while it does put just a slight restraint on what parts could be used.

Anyway have fun
BJ

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Post by sadrew »

AD797 in DynaRed too?

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Post by BJF »

sadrew wrote:AD797 in DynaRed too?
Hi,

No.

Hm, you know there would be angles that might be fun to discuss on distortion......

I told AD797 was used for a reason......what is the best merit of AD797 just of the datasheet?

Have fun
BJ

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Post by RnFR »

from the ds-


The AD797 is a very low noise, low distortion operational
amplifier ideal for use as a preamplifier. The low noise of
0.9 nV/√Hz and low total harmonic distortion of −120 dB at
audio bandwidths give the AD797 the wide dynamic range
necessary for preamps in microphones and mixing consoles.
Furthermore, the AD797’s excellent slew rate of 20 V/μs and
110 MHz gain bandwidth make it highly suitable for low
frequency ultrasound applications.
--------------

what is the "best" out of all of this, i'm not quite sure though.
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Post by chris_d »

RnFR wrote:from the ds-


The AD797 is a very low noise, low distortion operational
amplifier ideal for use as a preamplifier. The low noise of
0.9 nV/√Hz and low total harmonic distortion of −120 dB at
audio bandwidths give the AD797 the wide dynamic range
necessary for preamps in microphones and mixing consoles.
Furthermore, the AD797’s excellent slew rate of 20 V/μs and
110 MHz gain bandwidth make it highly suitable for low
frequency ultrasound applications.
--------------

what is the "best" out of all of this, i'm not quite sure though.
Bjorn has mentioned in the past considering the slew rate in picking ICs for his distortions, so i might be inclined to guess that. I have to do some reading on the subject myself.

-chris

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Post by chris_d »

If it is slew rate...

BJF, after reading only a small amount on slew rates, it seems that a lower rate chip, such as the old 4558 (SR=1) would tend to take a heavily clipped signal and turn it into a bit of a sawtooth sort of wave? Is that correct?

And that a very high slew rate such as on the AD797 would more "accurately" transmit the original clipped signal?

Would this come across as a clearer sound, one truer to the source? I do not have any high rate chips here to experiment with, and it will be quite some time before i am in a position to make a parts order to acquire some, but this is interesting to me.

-chris

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Post by BJF »

Hi,

Slewrate is a limitation defined as the voltage derivata of a sharply rising wave.......and as such it'd induce distortion and that is something that can be controlled by choice of OP amp device-

Now for MP pedals I'd need to lock designs at what can be repeated...........

There would be lots more but I will have to sleep

Have fun
BJ

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Post by downthemachine »

http://www.alldatasheet.com/datasheet-p ... AD797.html
Just thought i'd share the data sheet for the AD797, i'm impressed. but its what's
expected from Analog Devices, IMO

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Post by sevinisthenumber »

Layout?
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Magnus290
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Post by Magnus290 »

Hi There!

Is there anyone who has looked under the hood on this one yet. I do not have a unit in sight so dont know so much about it but it really sounds great.

Hope that there are somone out there....

Best regards Magnus

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