Skreddy - P19  [traced]

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Skreddy - P19

Postby method » 28 Feb 2012, 22:56

Knicked these off Teh Gear Page. :horsey:


P19.jpg




p192.jpg
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Re: Skreddy - P19

Postby Skreddy » 29 Feb 2012, 03:36

Hint: it's a Big Muff design with tweaks inspired by Cornish P1. Pretty much shifted the Pig Mine into the direction of the P1, ending up with fully half the components changing in the process. For every 1 component I used that was the same thing as Cornish, about 4 are different. Not a clone of anything per se, just tweaked to my liking with the goal of low noise and clarity.

BC550 transistors
560pf nfb filter caps
200R emitter resistors
custom tone stack

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Re: Skreddy - P19

Postby culturejam » 29 Feb 2012, 03:56

Classy as usual, Marc. :thumbsup
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Re: Skreddy - P19

Postby briggs » 29 Feb 2012, 10:43

New Skreddy :applause: Marc - Do you use Duncan's Tone Stack calc to prototype your tonestacks or do you just go by ear then model it up, or a bit of both?
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Re: Skreddy - P19

Postby Skreddy » 29 Feb 2012, 22:05

briggs wrote:New Skreddy :applause: Marc - Do you use Duncan's Tone Stack calc to prototype your tonestacks or do you just go by ear then model it up, or a bit of both?


I actually build my tone stacks by ear and then go back and enter the values I chose into Duncan's later, as a sanity check, to archive/catalog my tone stacks, and to develop those cool graphics for the webpage.
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Re: Skreddy - P19

Postby briggs » 01 Mar 2012, 11:02

Nice, and it makes sense - Whenever I spend hours modelling something specific up the first thing that happens when I start testing in in the real world is that I start tweaking values by ear to get the tone I'm after even if the model suggests it *should* sound more like how I "wanted" before I start tweaking. I guess it's just up to trusting your ears and knowing what part to tweak to get the result you're after...
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Re: Skreddy - P19

Postby MoonWatcher » 01 Mar 2012, 22:47

Skreddy wrote:...the goal of low noise...

...BC550 transistors...


If I want a low noise Muff, those are the exact transistors I've been using. Maybe not my faves, but certainly very low noise.
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Re: Skreddy - P19

Postby dap9 » 02 Mar 2012, 00:07

Skreddy wrote:Hint: it's a Big Muff design with tweaks inspired by Cornish P1. Pretty much shifted the Pig Mine into the direction of the P1, ending up with fully half the components changing in the process. For every 1 component I used that was the same thing as Cornish, about 4 are different. Not a clone of anything per se, just tweaked to my liking with the goal of low noise and clarity.

BC550 transistors
560pf nfb filter caps
200R emitter resistors
custom tone stack


Is there an "ideal" gain range for the BC550s? I recently went through almost all my trannies and measured the hFE (what's the proper abbreivation/capitalization?) so most of them are already labled. I have a Big Muff on the breadboard so it'd be cool to know which are the "ideal" ones. So far, my ears are really liking 5089s, but I remember the 550s being a close second.
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Re: Skreddy - P19

Postby Skreddy » 02 Mar 2012, 02:43

dap9 wrote:
Skreddy wrote:Hint: it's a Big Muff design with tweaks inspired by Cornish P1. Pretty much shifted the Pig Mine into the direction of the P1, ending up with fully half the components changing in the process. For every 1 component I used that was the same thing as Cornish, about 4 are different. Not a clone of anything per se, just tweaked to my liking with the goal of low noise and clarity.

BC550 transistors
560pf nfb filter caps
200R emitter resistors
custom tone stack


Is there an "ideal" gain range for the BC550s? I recently went through almost all my trannies and measured the hFE (what's the proper abbreivation/capitalization?) so most of them are already labled. I have a Big Muff on the breadboard so it'd be cool to know which are the "ideal" ones. So far, my ears are really liking 5089s, but I remember the 550s being a close second.


Depends on the sound you're after plus the transistor type. 300Hfe is okay for 2N5133's but too low for most other types. Some of my builds use different gains in different positions, e.g., 600, 700, 800, different positions all in the same build. I think the BC550's in the P19 are pretty much in the 600 zone; but even though that's a moderate/lowish gain for most transistor types (e.g., would be quite low for a 2N5088), the BC550 has to be treated like it's very high gain (bigger emitter resistor and bigger nfb filter cap) to keep hiss down and tone mellow.

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Re: Skreddy - P19

Postby dap9 » 03 Mar 2012, 05:14

Skreddy wrote:
dap9 wrote:
Skreddy wrote:Hint: it's a Big Muff design with tweaks inspired by Cornish P1. Pretty much shifted the Pig Mine into the direction of the P1, ending up with fully half the components changing in the process. For every 1 component I used that was the same thing as Cornish, about 4 are different. Not a clone of anything per se, just tweaked to my liking with the goal of low noise and clarity.

BC550 transistors
560pf nfb filter caps
200R emitter resistors
custom tone stack


Is there an "ideal" gain range for the BC550s? I recently went through almost all my trannies and measured the hFE (what's the proper abbreivation/capitalization?) so most of them are already labled. I have a Big Muff on the breadboard so it'd be cool to know which are the "ideal" ones. So far, my ears are really liking 5089s, but I remember the 550s being a close second.


Depends on the sound you're after plus the transistor type. 300Hfe is okay for 2N5133's but too low for most other types. Some of my builds use different gains in different positions, e.g., 600, 700, 800, different positions all in the same build. I think the BC550's in the P19 are pretty much in the 600 zone; but even though that's a moderate/lowish gain for most transistor types (e.g., would be quite low for a 2N5088), the BC550 has to be treated like it's very high gain (bigger emitter resistor and bigger nfb filter cap) to keep hiss down and tone mellow.


Thanks Marc. Speaking of different values in different positions - is there a "rule" for that... ie, higher gain in Q1? Or just go by ear?
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Re: Skreddy - P19

Postby Skreddy » 03 Mar 2012, 22:14

dap9 wrote:Thanks Marc. Speaking of different values in different positions - is there a "rule" for that... ie, higher gain in Q1? Or just go by ear?


Higher gains give you a hotter sound (more "modern," tend to boost upper mids) and more dynamic headroom, but also more "compressed" as the quiet parts are amplified more, yeah? (but can boost hum and hiss too). And lower gains in a fuzz can saturate better and get more sludgy and more mellow and soft ("vintagey" sounding).

The circuit's the palette, and you're the artist. There are no rules, only taste and preference.

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Re: Skreddy - P19

Postby gilmour_pugliese » 29 Mar 2012, 11:58

Hi, I read TRACED but I don't find the schematic... :scratch:
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Re: Skreddy - P19

Postby Cub » 30 Mar 2012, 08:04

gilmour_pugliese wrote:Hi, I read TRACED but I don't find the schematic... :scratch:

He does have a point there. :hmmm:
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Re: Skreddy - P19

Postby Skreddy » 30 Mar 2012, 10:08

Pretty much started this project by approximating the Cornish P1 (sans input buffer) but tuned it to my ear and preferences--a few ceramic caps here and there, carbon comp resistors, some minor resistor value tweaks, smaller input caps to both help articulation and reduce 60 cycle pickup hum, and a big .33uf cap (instead of typical .1uf) between tone stack and output stage to help the bottom end breathe, as it is tight in the lows.

It's really not a P1 clone, just used that as starting point/guide to help me capture the right balance of clarity and aggression to nail The Wall tones, which I've always found challenging and irresistible. After I've sold a few more, I'll probably be in more of a mood to publish the schematic. Hopefully that won't take me long. :hmmm:

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Re: Skreddy - P19

Postby Cub » 30 Mar 2012, 12:09

Splendid ! Hat's off to you, Marc, for being so forthcoming with all your tweaks and secrets ! :applause:
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Re: Skreddy - P19

Postby gilmour_pugliese » 30 Mar 2012, 14:02

Skreddy wrote:Pretty much started this project by approximating the Cornish P1 (sans input buffer) but tuned it to my ear and preferences--a few ceramic caps here and there, carbon comp resistors, some minor resistor value tweaks, smaller input caps to both help articulation and reduce 60 cycle pickup hum, and a big .33uf cap (instead of typical .1uf) between tone stack and output stage to help the bottom end breathe, as it is tight in the lows.

It's really not a P1 clone, just used that as starting point/guide to help me capture the right balance of clarity and aggression to nail The Wall tones, which I've always found challenging and irresistible. After I've sold a few more, I'll probably be in more of a mood to publish the schematic. Hopefully that won't take me long. :hmmm:


Thank you very much... The P-1 seems to be a modified Ram's Head, and in that case I'm OK with my replica...
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Re: Skreddy - P19

Postby Skreddy » 30 Mar 2012, 18:51

gilmour_pugliese wrote:
Skreddy wrote:Pretty much started this project by approximating the Cornish P1 (sans input buffer) but tuned it to my ear and preferences--a few ceramic caps here and there, carbon comp resistors, some minor resistor value tweaks, smaller input caps to both help articulation and reduce 60 cycle pickup hum, and a big .33uf cap (instead of typical .1uf) between tone stack and output stage to help the bottom end breathe, as it is tight in the lows.

It's really not a P1 clone, just used that as starting point/guide to help me capture the right balance of clarity and aggression to nail The Wall tones, which I've always found challenging and irresistible. After I've sold a few more, I'll probably be in more of a mood to publish the schematic. Hopefully that won't take me long. :hmmm:


Thank you very much... The P-1 seems to be a modified Ram's Head, and in that case I'm OK with my replica...
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:horsey:


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Re: Skreddy - P19  [traced]

Postby Skreddy » 16 Apr 2012, 23:52

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Re: Skreddy - P19

Postby Seiche » 17 Apr 2012, 10:39

what are D1-D4? Just 1N4148s?
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Re: Skreddy - P19

Postby Skreddy » 17 Apr 2012, 15:09

Seiche wrote:what are D1-D4? Just 1N4148s?


Basically. I have a special "Skreddy" recipe for my clipping diodes for the slightest touch of asymmetric clipping that doesn't sound so different in the final mix (after 2 stages of clipping), but just adds a little bit of depth and character. I'd like to reserve that one last piece of info as my own signature touch. I suspect that older Big Muffs might coincidentally share a similar profile because older diodes were probably less precisely made and matched back in the day (much like older transistors tend to vary hugely in gains compared to their new counterparts).
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