Skreddy - Mayo

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Re: Skreddy Pedals - Mayo

Postby Skreddy » 27 May 2008, 20:30

nokaster wrote:i wanted to and succeeded in understanding the big muff circuit. knowing what each component does etc...
making a vero layout thought me a lot.

but on the mayo i still have a few questions...
- why a higher collector voltage on Q2?

I just liked the tone better with a 56k/ground on the base of Q2 than the stock 100k. I can't say why exactly. It just gave it a less "hard" tone (compressed with a hot treble response) and more of a "juicy" (a tiny bit more touch sensitive and less "loud") kind of response.

- why split the collector resistor on Q4 in 2 resistors with the output at their joint?

I was getting way too much output volume, and I wanted to spread out the volume of the pot to where unity gain was a little higher setting and less touchy (without using audio taper pots--the originals used all B100K).

- i guess the 47pF after the tone section filters some highs?

Yeah. This is to smooth out the tone to make it sound closer to the original (since I didn't have NOS circa 1970 transistors).

i love the sound of my clone A LOT!
AB'd it with a little big muff last week... LBM s*cks...

8)


Yeah; I'm not sure why EH didn't do just a little bit more extensive product development on their BMP reissues to get them to sound smooth like the originals. :scratch:
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Re: Skreddy Pedals - Mayo

Postby nokaster » 27 May 2008, 21:51

thx again for your help!!!!
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Re: Skreddy Pedals - Mayo

Postby vanguard » 28 May 2008, 13:59

nokaster wrote:I hope the maker of the skreddy mayo doesn't mind me posting this, but i made a vero layout using the schematic in the first post of this thread.
Thought maybe some of you might like to use it to build a mayo (or any muff variation).
It is verified and working and sounds great!
I have added a polarity protection diode, a pull down resistor, an anti rfi cap and a LED resistor.

Image


8)


so i just finished building this great layout (thanks, nocaster!!). it sounds great, but i have one problemo: the output is REALLY quiet. like i can only get like 1/4 the way to unity cranked. any ideas as to how to troubleshoot? i used really weird transistors first off. the NET equivalent to the 2n5133 was the nte161, which is an NPN video IF amp with four legs! the fourth leg is "case" which i just left suspended in the air. the gain on this tranny is also only 60 Hfe. could this be the problem? i also used a 1.1m resistor rather than where it called for 1.5m, because that's what i had around.
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Re: Skreddy Pedals - Mayo

Postby nokaster » 28 May 2008, 19:22

i had a volume problem myself at first, but turned out i had a really small solder bridge between strips that wasn't supposed to be there.

i think your problem are those transistors.

the layout works great with bc549 etc.
any NPN transistor, gain from 250 and up...
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Re: Skreddy Pedals - Mayo

Postby RiGLEY » 28 May 2008, 20:19

I will try to build this using your vero layout nokaster. Thank you. I don't have the exact type of resistors, capacitors, etc., but I guess it will only modify the sound, and not make it sound radically worse.
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Re: Skreddy Pedals - Mayo

Postby nokaster » 28 May 2008, 21:13

first of, thx for the nice comments on my layout and thx for using it!

as far as exact component values goes, i'd try to stay as close as posible if i were you... skreddy did think about this!

otherwise, take a look at the schematics of all the big muff variation you can find. that way you can check out which values are within a usable range.

please report back after using the layout!
but all praise goes to the man who tweaked the big muff to a mayo!!! = SKREDDY!
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Re: Skreddy Pedals - Mayo

Postby RiGLEY » 29 May 2008, 00:11

Yeah, I will use the correct values. But I don't have carbon resistors right now. I think I will build it with metal. Less mojo. How to wire the "scoop/flat" mid-mod? I have an spdt on-on switch. Can I use it somehow?
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Re: Skreddy Pedals - Mayo

Postby Skreddy » 29 May 2008, 01:52

RiGLEY wrote:Yeah, I will use the correct values. But I don't have carbon resistors right now. I think I will build it with metal. Less mojo. How to wire the "scoop/flat" mid-mod? I have an spdt on-on switch. Can I use it somehow?

You can use any switch for the scoop/flat mod.
Image

For this message the author Skreddy has received thanks:
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Re: Skreddy Pedals - Mayo

Postby Ed G. » 29 May 2008, 02:09

Skreddy,
Since you're the Muff connoisseur, what's the deal with the 90's BMPs? For some reason, people are paying a lot of money for these on ebay. Is this a bunch of lemmings buying some hype, or is there something to these pedals?

My experience with BMPs is in the mid 90s, I had a big Fender Bassman 135 and a BMP. It's one of the ones with that lamb's head. I also had a Rat, but the BMP sounded way badder. I didn't care for the BMP as much at low volumes, but cranked up, it killed. The bassman was one of those ultralinear Fenders, it had huge transformers and was loud as all get-out and couldn't distort on its own. Loud and clean was all it did.
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Re: Skreddy Pedals - Mayo

Postby vanguard » 29 May 2008, 02:17

so i got some different transistors in there and changed that resistor to a 1.5m and still very little output. all three pots are 100k linear, right? any other ideas what it could be?
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Re: Skreddy Pedals - Mayo

Postby nokaster » 29 May 2008, 07:22

it's very early here in belgium and i have to leave for work, so all i can say is check all your strips for unwanted solder bridges and get out the multimeter and check the voltages on your transistors.

the correct voltages are somewhere in this thread!
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Re: Skreddy Pedals - Mayo

Postby RiGLEY » 29 May 2008, 08:15

Thanks Skreddy!
Approximately what hFE should I use? I will try some different transistors. I will buy some BC549's since nokaster had good results with them. There are 3 types of this transistor: A, B and C. A has the least (110 ~ 220), C has the most (420 ~ 800) gain.
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Re: Skreddy Pedals - Mayo

Postby paperhouse » 29 May 2008, 08:23

Ed G. wrote:Skreddy,
Since you're the Muff connoisseur, what's the deal with the 90's BMPs? For some reason, people are paying a lot of money for these on ebay. Is this a bunch of lemmings buying some hype, or is there something to these pedals?

My experience with BMPs is in the mid 90s, I had a big Fender Bassman 135 and a BMP. It's one of the ones with that lamb's head. I also had a Rat, but the BMP sounded way badder. I didn't care for the BMP as much at low volumes, but cranked up, it killed. The bassman was one of those ultralinear Fenders, it had huge transformers and was loud as all get-out and couldn't distort on its own. Loud and clean was all it did.


A "lamb's head" muff (otherwise known as "ram's head") is from the early 70's. They sell for $400+ nowadays. The green/gray Russian muffs from the 90's are selling for $150+ when they originally sold for $50 or so. They have a slightly less scooped tone stack and strange, unmarked Russian transistors. As far as I know, no one has been able to identify the transistors, which are integral to their sound. The tone stack can be simulated very easily, however.
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Re: Skreddy Pedals - Mayo

Postby Skreddy » 29 May 2008, 14:24

RiGLEY wrote:Thanks Skreddy!
Approximately what hFE should I use? I will try some different transistors. I will buy some BC549's since nokaster had good results with them. There are 3 types of this transistor: A, B and C. A has the least (110 ~ 220), C has the most (420 ~ 800) gain.

I would probably use the "B" group to make some new muff clones using off-the-shelf rather than NOS parts. For more modern/aggressive tone, go for "C" though. Or try using a single "C" as the input and "B"s everywhere else.
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Re: Skreddy Pedals - Mayo

Postby Lovepedal Detective » 29 May 2008, 17:32

Skreddy wrote:
nokaster wrote:- why a higher collector voltage on Q2?


I just liked the tone better with a 56k/ground on the base of Q2 than the stock 100k. I can't say why exactly. It just gave it a less "hard" tone (compressed with a hot treble response) and more of a "juicy" (a tiny bit more touch sensitive and less "loud") kind of response.


Some versions do not have anything from ground to base on Q2 correct?
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Re: Skreddy Pedals - Mayo

Postby nokaster » 29 May 2008, 17:46

i think the triangle indeed lacks that resistor.
as well as the 470/560 pF cap across B and C of Q1.
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Re: Skreddy Pedals - Mayo

Postby Skreddy » 29 May 2008, 17:50

Lovepedal Detective wrote:
Skreddy wrote:
nokaster wrote:- why a higher collector voltage on Q2?


I just liked the tone better with a 56k/ground on the base of Q2 than the stock 100k. I can't say why exactly. It just gave it a less "hard" tone (compressed with a hot treble response) and more of a "juicy" (a tiny bit more touch sensitive and less "loud") kind of response.


Some versions do not have anything from ground to base on Q2 correct?

None that I have seen in real life. I've tried it and don't recommend it.

nokaster wrote:i think the triangle indeed lacks that resistor.
as well as the 470/560 pF cap across B and C of Q1.

Again; none that I've seen in real life lack those parts.
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Re: Skreddy Pedals - Mayo

Postby nokaster » 29 May 2008, 17:57

i can't imagine it sounding good.
but it's the word on the net...
when you read the byoc instructions they recommend adding these components, although their large beaver kit is supposed to be a triangle clone.

i'm waiting on a parts order to build 3 different versions and a "creamy dreamer".
just for fun, to compare them and because i love this circuit.
i'll try the triangle without the 2 components, but i fear it won't be good.
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Re: Skreddy Pedals - Mayo

Postby nokaster » 29 May 2008, 18:13

i want to post a V2 for my layout, which can be used by those who don't want the split up resistance from 9V to C of Q4.
(i put in 2 led resistors because i don't like resistors with long leads across the board)

skreddy's Cx (after the tone pot, 47pF to ground, is still there)

as far as values go... there are tons of schematics...
so for those interested there is a file with values for many versions.

please comment/correct the values if i'm wrong. just collected them from the net.


Image

Image
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Re: Skreddy Pedals - Mayo

Postby Skreddy » 29 May 2008, 22:15

Don't know where you got the info, but there are tons of errors in the Mayo list.
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