Pete Cornish - P-2 guts

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
User avatar
Ben N
Cap Cooler
Information
Posts: 506
Joined: 12 Dec 2008, 03:34
my favorite amplifier: Ampeg J12D Jet
Location: Israel
Has thanked: 192 times
Been thanked: 53 times

Post by Ben N »

Or these?
Image

User avatar
Dirk_Hendrik
Old Solderhand
Information
Posts: 4193
Joined: 03 Jul 2007, 08:44
Location: Old Amsterdam
Has thanked: 232 times
Been thanked: 887 times
Contact:

Post by Dirk_Hendrik »

silverface wrote:Oh about the seals, these come very close:

http://www.labelsourceonline.co.uk/scri ... oduct=7342

nope... they don't. Completely different :(
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

User avatar
Dirk_Hendrik
Old Solderhand
Information
Posts: 4193
Joined: 03 Jul 2007, 08:44
Location: Old Amsterdam
Has thanked: 232 times
Been thanked: 887 times
Contact:

Post by Dirk_Hendrik »

biffa wrote:I think people react to his success
I've said it too,as kilby just did,no pro musician would keep a pedal if it didn't do exactly what he wanted it to do
People don't like him,because many guitarists are in awe of his work
Sour grapes...
True. And up for wondrin.
We all agree that a pedal is far more than the price of it's components. The builder's gotta live, gotta may the rent/mortgage, distribution, advertizing, spend time on component sourcing (non-declarable hours) etc etc. That's a lot of overhead and needs to be taken into account. (I keep R&D out since that's a factor when fully developing and does only partially account for clones (in case of an experienced engineer))

And then we start to dissect a cornish unit. Reputation caused absence of distribution, advertizing and all that stuff. Job well done, that's a price cut! respect all over.

dissecting the thing it was..
That's about 4 to 6 hours of work and some 40 euro's in components (bulk) for 600 euro's selling price. Build 10 a month (that's 40-60 hours) and you make a fairly good living. Hmm... at 160 hours a month I make less... sour grapes.. Not really... but with the nagging feeling somebody is wetting hus bottom end lauging.

And doing a damn fine job keeping his reputation by use of some red paint and 2 vinyl labels.. Wow !
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

User avatar
plugzzzz
Breadboard Brother
Information
Posts: 68
Joined: 25 Aug 2009, 15:24

Post by plugzzzz »

i dunno if someone already post this watch this video



if somebody gooped this pedal (TopTone DG-1) you cop Cornish P-2 they sound identical to me

User avatar
Alex Frias
Resistor Ronker
Information
Posts: 270
Joined: 19 Dec 2007, 16:05
Has thanked: 10 times
Been thanked: 14 times

Post by Alex Frias »

I agree, sound and feel are very subjective tihings.

I've tried my very old Big Muff with a good Hiwatt amplifier and that "liquid metal" sound was already there, when I added a bit of echo, well, you know...

User avatar
benfscott
Information
Posts: 29
Joined: 10 Aug 2009, 02:41

Post by benfscott »

Far more importantly, could someone point me to where i can buy those cool little wiring plates that go over the pins on the bypass switch in the OP?

Cheers :)

User avatar
Greg
Old Solderhand
Information
Posts: 3047
Joined: 03 Nov 2007, 09:35
my favorite amplifier: Tophat Emplexador & Supreme 16.
Completed builds: LOTS..
Location: Australia
Has thanked: 65 times
Been thanked: 164 times

Post by Greg »

benfscott wrote:Far more importantly, could someone point me to where i can buy those cool little wiring plates that go over the pins on the bypass switch in the OP?

Cheers :)
They're called PCB's :mrgreen:

viewtopic.php?f=13&t=7799&hilit=daughter

http://www.smallbearelec.com/Detail.bok?no=870
culturejam wrote: We are equal opportunity exposure artists.

User avatar
mictester
Old Solderhand
Information
Posts: 2923
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 32 times
Been thanked: 844 times
Contact:

Post by mictester »

controller700 wrote:What da f**k?!
My pulse goes up when I read shit like:
"You can´t see inside the cases - a white strip seals each unit, and if you break it then the warranty is viod - but we´re told that the components are top notch." :slap:

Damn, what´s going on at cornish?!
He copies a Big Muff and puts a sealing on his boxes, so that no one can copy his copy? That´s sick!!
Reminds me of Roger Mayer´s story about Jimi´s Octavio...
I've just had a Big Muff Pi..... sorry, Cornish P1 here. It had failed. It's quite old, and has seen a lot of gigging (the case was quite chipped and dented). Opening it up, the boards were gooped, but not with the usual paint - it had what looked like Starbucks wooden coffee stirrers glued to each edge of each board with the goop poured into the "tray" that was formed. A quick look confirmed that it was just a Big Muff Pi. Nothing else. There might be a couple of component changes - it sounds slightly different to my BMPs - but it's nothing really significant. The failure was due to a wire breaking off the volume pot - the wiring loom was just loose inside the (oversized) box, and the wire had fractured with repeated movement. Pretty poor for someone who's meant to make "reliable" pedals! It was a five minute fix and the owner had a gig shortly after the repair last night, so I didn't bother taking photos. It looked very like the one at the head of this thread.
"Why is it humming?" "Because it doesn't know the words!"

User avatar
ryanuk
Solder Soldier
Information
Posts: 211
Joined: 29 May 2008, 11:18
Has thanked: 29 times
Been thanked: 28 times

Post by ryanuk »

mictester wrote:
controller700 wrote:What da f**k?!
My pulse goes up when I read shit like:
"You can´t see inside the cases - a white strip seals each unit, and if you break it then the warranty is viod - but we´re told that the components are top notch." :slap:

Damn, what´s going on at cornish?!
He copies a Big Muff and puts a sealing on his boxes, so that no one can copy his copy? That´s sick!!
Reminds me of Roger Mayer´s story about Jimi´s Octavio...
I've just had a Big Muff Pi..... sorry, Cornish P1 here. It had failed. It's quite old, and has seen a lot of gigging (the case was quite chipped and dented). Opening it up, the boards were gooped, but not with the usual paint - it had what looked like Starbucks wooden coffee stirrers glued to each edge of each board with the goop poured into the "tray" that was formed. A quick look confirmed that it was just a Big Muff Pi. Nothing else. There might be a couple of component changes - it sounds slightly different to my BMPs - but it's nothing really significant. The failure was due to a wire breaking off the volume pot - the wiring loom was just loose inside the (oversized) box, and the wire had fractured with repeated movement. Pretty poor for someone who's meant to make "reliable" pedals! It was a five minute fix and the owner had a gig shortly after the repair last night, so I didn't bother taking photos. It looked very like the one at the head of this thread.
I'm still wondering about the 5th transistor that can be seen on the main board?? Wondererd whether this quote from PC's site had the answer...

"My system, which I devised in the early 70's, is to feed the guitar into a fixed high impedance load, which is identical to the amp input, and then distribute the signal to the various effects and amps by low impedance buffered feeds. This gives a constant signal level and tonal characteristics, which do not change at all when effects are added."

Perhaps the seperate board is a "fixed high imedance load" and then the 5th transistor forms the buffer?? Not sure that makes any sense??

User avatar
silverface
Solder Soldier
Information
Posts: 156
Joined: 25 Aug 2008, 19:33
Location: Point Place, Wisconsin
Has thanked: 3 times
Been thanked: 10 times

Post by silverface »

All will be revealed when the G2 gets released :)

User avatar
mictester
Old Solderhand
Information
Posts: 2923
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 32 times
Been thanked: 844 times
Contact:

Post by mictester »

ryanuk wrote:
I'm still wondering about the 5th transistor that can be seen on the main board?? Wondered whether this quote from PC's site had the answer...

"My system, which I devised in the early 70's, is to feed the guitar into a fixed high impedance load, which is identical to the amp input, and then distribute the signal to the various effects and amps by low impedance buffered feeds. This gives a constant signal level and tonal characteristics, which do not change at all when effects are added."

Perhaps the separate board is a "fixed high impedance load" and then the 5th transistor forms the buffer?? Not sure that makes any sense??
The extra is a FET buffer. It's high Z in and 10k out. It's just that. Nothing more. He just wanted to prevent the first stage of his BMP... sorry P1 loading down the guitar.

If you look at the original BMP circuit, you'll see that the input Z is lower than with modern effects. This actually is slightly beneficial in terms of "tone" from the BMP, because it'll load down the pickup, so tending to roll off the high end, and mellow out the tone a bit. However, the original BMP, without proper bypass, sucked tone in bypass mode. That's why "true bypass" became a popular mod for the BMP.

I also noticed that Cornish has added a capacitor across the "sustain" pot - probably to roll the top end off a bit to keep the tone the same as it was without the FET buffer!
"Why is it humming?" "Because it doesn't know the words!"

User avatar
analogguru
Old Solderhand
Information
Posts: 3238
Joined: 26 Jun 2007, 13:58
Been thanked: 124 times
Contact:

Post by analogguru »

mictester wrote: The extra is a FET buffer. It's high Z in and 10k out. It's just that. Nothing more.
:hmmm: Haven´t seen a FET in the G2, only BC549.

But I have seen a buffered buffer (2 buffers in a chain, yes...).

Input impedance of each buffer is approx. 1,5 MOhm, output impedance is about 1k (in an emitter follower configuration the output impedance is lower than the emitter resistor).

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

User avatar
ryanuk
Solder Soldier
Information
Posts: 211
Joined: 29 May 2008, 11:18
Has thanked: 29 times
Been thanked: 28 times

Post by ryanuk »

analogguru wrote:
mictester wrote: The extra is a FET buffer. It's high Z in and 10k out. It's just that. Nothing more.
:hmmm: Haven´t seen a FET in the G2, only BC549.

But I have seen a buffered buffer (2 buffers in a chain, yes...).

Input impedance of each buffer is approx. 1,5 MOhm, output impedance is about 1k (in an emitter follower configuration the output impedance is lower than the emitter resistor).

analogguru
So when the unit is "on" we have... INPUT BUFFER > "BIG MUFF BUFFER" > BMP CIRCUIT. And there's a tap between the 2 buffers for a side-chain bypass, right?

Still not sure why he needs 2 buffers - surely one will prevent any degeredation of signal? Or is it so that in each event (on/off) the input buffer output sees a high impedance load (i.e. tube amp or BMP circuit)?

User avatar
JshDnls
Breadboard Brother
Information
Posts: 74
Joined: 27 Dec 2009, 19:37
Has thanked: 2 times
Been thanked: 4 times

Post by JshDnls »

silverface wrote:All will be revealed when the G2 gets released :)
Any idea when this will happen ? No real news about this since October.

User avatar
silverface
Solder Soldier
Information
Posts: 156
Joined: 25 Aug 2008, 19:33
Location: Point Place, Wisconsin
Has thanked: 3 times
Been thanked: 10 times

Post by silverface »

ryanuk wrote:
analogguru wrote:
mictester wrote: The extra is a FET buffer. It's high Z in and 10k out. It's just that. Nothing more.
:hmmm: Haven´t seen a FET in the G2, only BC549.

But I have seen a buffered buffer (2 buffers in a chain, yes...).

Input impedance of each buffer is approx. 1,5 MOhm, output impedance is about 1k (in an emitter follower configuration the output impedance is lower than the emitter resistor).

analogguru
So when the unit is "on" we have... INPUT BUFFER > "BIG MUFF BUFFER" > BMP CIRCUIT. And there's a tap between the 2 buffers for a side-chain bypass, right?
That's correct, at least for the G-2 and P-2.
Still not sure why he needs 2 buffers - surely one will prevent any degeredation of signal? Or is it so that in each event (on/off) the input buffer output sees a high impedance load (i.e. tube amp or BMP circuit)?
Could be, I don't know..

User avatar
ryanuk
Solder Soldier
Information
Posts: 211
Joined: 29 May 2008, 11:18
Has thanked: 29 times
Been thanked: 28 times

Post by ryanuk »

biffa wrote:This thread is about one of cornishs pedals,and guess what?
It's bash the builders we don't like time again
A lot of posts are about the pedal,but the thread gets riddled with the same old story
"The Strip! The cheap components!"
After the air force giving him a top notch electrical background,are we saying he doesn't give a damn,and just knocks out old tat?
We already know all there is to know about how certain people feel about him
Can we just leave the knocking at him,out?
+1 on your sentiment. I think there is a justification for owning a Pete Cornish P-2.

We already know its essentially a BMP circuit. However, its been modified and ruggedised to be able to stand up to a tour environment e.g. input/output/switch wiring is screened, attention has been given to the input impdedance of the circuit and bypass etc. I even read somewhere that PC ensures that all components can stand up to the varying ambient temperatures which the tour inherently brings. The entire pedal has been well thought out. It doesnt look pretty but it doesnt need to - function over form.

That said, I cannot justify the COST of owning a Pete Cornish P-2.

But do I need one??... no

Clearly these units are aimed at touring musicians who demand a more rugged unit with a classic sound. If you arent a pro, and you arent touring 300 days a year, then a regular Big Muff (vintage or otherwise) should be fine. Take the Edge for example - hes got a regular BMP sitting on top of his racks.

With regard to sound - I dont think we can judge it on people who've built from the schem provided earlier, as I wouldn't class it as being verified. We need proper pics of a degooped P-2 in order to RE it. Chances are slim unless the other recent P-2 thread pans out!!

My conclusion - we shouldnt slate PC. He's building for a particular market which would not normally attract many users of this forum usually. Furthermore, at least he's making an effort to ensure his products are road-worhty. There are LOTS of boutique "manufacturers" that charge the earth for true-bypass switly boxes and fender knobs (oooohh!!) ... but inside they're poorly wired crap.

User avatar
mictester
Old Solderhand
Information
Posts: 2923
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 32 times
Been thanked: 844 times
Contact:

Post by mictester »

ryanuk wrote:
My conclusion - we shouldnt slate PC.
Why not? If he did anything original, it might be interesting. However, all he produces are copies of well-known effects using components he buys from RS (he believes that Farnell provide sub-standard components because they're so cheap compared to RS). He uses over-sized boxes, and claims that this makes his boxes more "reliable". It doesn't. I've seen plenty of his gear that has failed in normal use. He uses BC109Cs for almost everything.

I've also seen plenty of cheap crap like Colorsound stuff with the controls snipped off (so they can't be altered - the owner gets it just the way he wants it, then snaps the knobs off and uses Araldite to stick the pot where it is!). This junk has lasted for 30 years and is still in constant, touring use!

I'm now determined to build something like a BMP, and gold-plate a diecast box for it, and sell is for £2500 at auction. It's got to be done - there'll be some clueless jerk who'll believe that the gold plating makes a difference to the way it sounds.....
"Why is it humming?" "Because it doesn't know the words!"

User avatar
soulsonic
Old Solderhand
Information
Posts: 3880
Joined: 27 Jun 2007, 03:38
my favorite amplifier: Traynor YVM-1
Completed builds: too many!
Location: Morgantown, WV
Has thanked: 183 times
Been thanked: 468 times
Contact:

Post by soulsonic »

mictester wrote:I'm now determined to build something like a BMP, and gold-plate a diecast box for it, and sell is for £2500 at auction. It's got to be done - there'll be some clueless jerk who'll believe that the gold plating makes a difference to the way it sounds.....
I've thought about doing this for awhile now. :lol:
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

User avatar
mictester
Old Solderhand
Information
Posts: 2923
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 32 times
Been thanked: 844 times
Contact:

Post by mictester »

soulsonic wrote:
mictester wrote:I'm now determined to build something like a BMP, and gold-plate a diecast box for it, and sell is for £2500 at auction. It's got to be done - there'll be some clueless jerk who'll believe that the gold plating makes a difference to the way it sounds.....
I've thought about doing this for awhile now. :lol:
A friend of mine has an electro-plating works, and just for the fun of it, we tin-plated some diecast boxes. They looked amazing - with a mirror finish! My nephew got three pedals built in these cases, and everyone who sees them asks "Where did you get those?". Next time I see him, I'll photograph them so you can see them.
"Why is it humming?" "Because it doesn't know the words!"

User avatar
MoonWatcher
Diode Debunker
Information
Posts: 715
Joined: 28 Jul 2008, 12:27
Has thanked: 40 times
Been thanked: 52 times

Post by MoonWatcher »

biffa wrote:I'm sure Gilmour isn't up on all the technical know-how to build his own stuff
So he must surely listen to a lot of gear(over many years at the top of his game)and choose what sounds best
Actually, David has repeatedly been on the record as saying that there isn't anything particularly stellar about anything in his rig. He has even mentioned that if he needed to reproduce it, he could walk into the typical music store with a modest list, and buy mainly off-the-shelf gear.

That said, the two things that Gilmour has absolutely required over the years is tonal consistency and durability. And low noise operation. This was the main reason for the buffering of some very standard effects (i.e. stock EH, Boss, and even Sovtek variations of the EH Muffs). The durability issue was actually tackled by Cornish building the effects into the pedalboard, so that individual enclosure jostling was not an issue.

Gilmour also required the buffering because he's a pedal stacker at heart, and it allowed for consistent volume levels while switching effects in and out.

Just look at his signature Black Strat for proof about the generic nature of his equipment. The "custom pickups" are a Seymour Duncan SSL-1 that has been replicated exactly (since there is some variation), and a pair of stock Fender middle and neck pickups that have been replicated (since there was HUGE variation).

...And during the 80's, about a half dozen '62 and '57 RI Strats were "built" - all basically the same. A standard issue alder body, and a pile of '57 RI necks. All were fitted with EMG pickups in around '85. Two of them were candy apple red, and one of those became the primary one used during gigs. There were also a pair of cream colored RI bodies, and one in Fiesta Red.

Post Reply