Catalinbread Manx Loaghtan [guts]

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Re: Catalinbread Manx Loaghtan [guts]

Postby mmolteratx » 04 May 2011, 03:09

Crap. C13 isn't supposed to be connected to +9V. Disregard the last one.
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Re: Catalinbread Manx Loaghtan [guts]

Postby lbj273 » 04 May 2011, 03:34

Its definitely a baxandall, Catalinbread has admitted as much. I wouldn't be surprised to see them using it more in future builds, they have talked about how much they love it.
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Re: Catalinbread Manx Loaghtan [guts]

Postby Nocentelli » 04 May 2011, 06:40

I'm going to guess those 470J caps are 470pf - That would match with most other BMP schematics I've seen.
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Re: Catalinbread Manx Loaghtan [guts]

Postby culturejam » 04 May 2011, 07:00

Nocentelli wrote:I'm going to guess those 470J caps are 470pf - That would match with most other BMP schematics I've seen.

470p is more common for a James/Baxandall.

The cap marked "470j" on the schematic is part of the Bax stack, and not part of the normal Muff circuit. The "stock" value in a Bax stack for that cap is 330p, so 470p makes a lot of sense.

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Re: Catalinbread Manx Loaghtan [guts]

Postby mmolteratx » 04 May 2011, 07:02

Nocentelli wrote:I'm going to guess those 470J caps are 470pf - That would match with most other BMP schematics I've seen.


That's what I was guessing, though I was told they were 47pF since I've never seen that code before. But that just wouldn't make any sense. So 470pF it is.
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Re: Catalinbread Manx Loaghtan [guts]

Postby Hides-His-Eyes » 04 May 2011, 07:08

freq67 wrote:The reason I hate that ground is because of the oxidation, corrosion issue.Grounds should ALWAYS be connected either mechanically(nut ,bolt and star washer) or by solder. Just because something looks slick or cool means it's worth a shit. I think it's lazy and any builder of any electronic equipment would call it what it is ....bullshit.


Aluminium is already corroded. What's the spring made of?
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Re: Catalinbread Manx Loaghtan [guts]

Postby culturejam » 04 May 2011, 07:10

mmolteratx wrote:That's what I was guessing, though I was told they were 47pF since I've never seen that code before. But that just wouldn't make any sense. So 470pF it is.

Usually, the last digit on ceramic caps is the multiplier (number of zeroes to add to the first two digits). So 470 is usually 47pF. But I have seen some caps that just give the straight value. I have some 180pF caps that just say "180j", for example. But I have 470pF caps that are marked 471.

Seems to be that if they have the tolerance letter included (j, k, etc), the numbers are the actual value. If not, it's first two digits + multiplier third digit.

But caps are weird, and I'm sure there is an exception to all of the above.
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Re: Catalinbread Manx Loaghtan [guts]

Postby mmolteratx » 04 May 2011, 07:27

That's why I just stick to WIMAs. I like the value printed on the side. No bull shit. :lol: Also the reason I use RN series resistors.
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Re: Catalinbread Manx Loaghtan [guts]

Postby Nocentelli » 04 May 2011, 08:11

culturejam wrote:
Nocentelli wrote:I'm going to guess those 470J caps are 470pf - That would match with most other BMP schematics I've seen.

470p is more common for a James/Baxandall.

The cap marked "470j" on the schematic is part of the Bax stack, and not part of the normal Muff circuit. The "stock" value in a Bax stack for that cap is 330p, so 470p makes a lot of sense.

:thumbsup


Ah, I was referring to the 470J caps in the collector-base feedback loops...
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Re: Catalinbread Manx Loaghtan [guts]

Postby Ice-9 » 04 May 2011, 09:13

The cap will definately be a 470p. I had the same issue when i reversed the Catalinbread Formula 5. The cap is marked as 470j which by every standard should be 47p but it was 100% 470p.
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Re: Catalinbread Manx Loaghtan [guts]

Postby batteryacidtea » 04 May 2011, 09:22

I'm re-doing the schematics above in Eagle, and I see two R19, both measuring 2M. Is that right and it's just a typo? As soon as I finish I'll post the files here, so anyone that want's to give a shot at doing nice layouts and stuff won't have to draw it again.
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Re: Catalinbread Manx Loaghtan [guts]

Postby deltafred » 04 May 2011, 10:21

Hides-His-Eyes wrote:
freq67 wrote:The reason I hate that ground is because of the oxidation, corrosion issue.Grounds should ALWAYS be connected either mechanically(nut ,bolt and star washer) or by solder. Just because something looks slick or cool means it's worth a shit. I think it's lazy and any builder of any electronic equipment would call it what it is ....bullshit.


Aluminium is already corroded. What's the spring made of?


I know the aluminium is corroded, that's why I removed the corrosion with emery cloth before applying the smear of grease.

The spring will be steel with probably nicklel plating, although it may be chrome, difficult to tell from a photo.
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Re: Catalinbread Manx Loaghtan [guts]

Postby Hides-His-Eyes » 04 May 2011, 10:25

I meant that given it works even with corroded aluminium, there's no point worrying about the aluminium corroding. I wasn't hating on the grease method. ;)
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Re: Catalinbread Manx Loaghtan [guts]

Postby Greg » 04 May 2011, 11:55

freq67 wrote:The reason I hate that ground is because of the oxidation, corrosion issue.Grounds should ALWAYS be connected either mechanically(nut ,bolt and star washer) or by solder. Just because something looks slick or cool means it's worth a shit. I think it's lazy and any builder of any electronic equipment would call it what it is ....bullshit.


I agree with you.. it's a poor method of grounding.. weak physical contact, and aluminium oxide is an excellent insulator (do a search.. it's one of the best).
The extra care that deltafred takes will help for sure, but there's no such care in the production pedal.

Galvanic corrosion occurs between steel and aluminium, irrespective of contact with air.
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Re: Catalinbread Manx Loaghtan [guts]

Postby culturejam » 04 May 2011, 13:02

Greg_G wrote:I agree with you.. it's a poor method of grounding.. weak physical contact, and aluminium oxide is an excellent insulator (do a search.. it's one of the best).

So then why don't they just use a plastic spring? Problem solved! :horsey:






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Re: Catalinbread Manx Loaghtan [guts]

Postby Hides-His-Eyes » 04 May 2011, 13:09

Greg_G wrote:
freq67 wrote:The reason I hate that ground is because of the oxidation, corrosion issue.Grounds should ALWAYS be connected either mechanically(nut ,bolt and star washer) or by solder. Just because something looks slick or cool means it's worth a shit. I think it's lazy and any builder of any electronic equipment would call it what it is ....bullshit.


I agree with you.. it's a poor method of grounding.. weak physical contact, and aluminium oxide is an excellent insulator (do a search.. it's one of the best).
The extra care that deltafred takes will help for sure, but there's no such care in the production pedal.

Galvanic corrosion occurs between steel and aluminium, irrespective of contact with air.


Not disagreeing with you, but ALL our case grounding techniques rely on getting some kind of connection through the oxide, short of putting a rivet in. People either ground to pots or through the sockets.
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Re: Catalinbread Manx Loaghtan [guts]

Postby Greg » 04 May 2011, 13:29

Hides-His-Eyes wrote:Not disagreeing with you, but ALL our case grounding techniques rely on getting some kind of connection through the oxide, short of putting a rivet in. People either ground to pots or through the sockets.


True.. if your shield is diecast aluminium, then you have to make a connection to that material.. but considering the nature of that material (highly corrosive and a heavily insulating oxide) if you were designing something for a critical situation, would you rather rely on the connection formed with a screwed fastener or a floating spring ?

All these diecast boxes get blotchy and spotty with oxidation after a few years if they're unprotected.
Then you get a leaky battery or just a humid environment and some rust forms on the spring.
I'm sure there'll be a decent connection there for a few years, but after that who knows.

I'm not saying it's a terrible thing.. it's a functional solution that makes for quicker and easier builds.. like board mounted 9V jacks.
But it's not a great way to do it in the long term.
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Re: Catalinbread Manx Loaghtan [guts]

Postby deltafred » 04 May 2011, 13:30

Greg_G wrote:
freq67 wrote:The reason I hate that ground is because of the oxidation, corrosion issue.Grounds should ALWAYS be connected either mechanically(nut ,bolt and star washer) or by solder. Just because something looks slick or cool means it's worth a shit. I think it's lazy and any builder of any electronic equipment would call it what it is ....bullshit.


I agree with you.. it's a poor method of grounding.. weak physical contact, and aluminium oxide is an excellent insulator (do a search.. it's one of the best).
The extra care that deltafred takes will help for sure, but there's no such care in the production pedal.

Galvanic corrosion occurs between steel and aluminium, irrespective of contact with air.


I agree, it is not ideal but I hate wires soldered to PCBs unless they are properly strain relieved. I worked for 30+ years in the aircraft industry and have a fair amount of experience with aluminium alloys and corrosion. Trying to get a good 'bond' (a resistance down in the milli-ohms) and keep it low resistance as opposed to just a 'ground' is a major problem, even with star washers.

I fitted my spring on the jack ground so eveytime I plug in or out it moves the plastic jack body slightly so will tend to rub the connections together. If it does go high resistance I will know immediately as it will buzz slightly. I am interested to see how long it lasts and will post back if I have any trouble.

I initially tried it without the spring and it buzzed until I touched the case, very much like loosing your bridge ground on a guitar.
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Re: Catalinbread Manx Loaghtan [guts]

Postby mmolteratx » 04 May 2011, 19:09

batteryacidtea wrote:I'm re-doing the schematics above in Eagle, and I see two R19, both measuring 2M. Is that right and it's just a typo? As soon as I finish I'll post the files here, so anyone that want's to give a shot at doing nice layouts and stuff won't have to draw it again.


It's a labeling error. There are two 2M resistors to bias the JFET.
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Re: Catalinbread Manx Loaghtan [guts]

Postby batteryacidtea » 04 May 2011, 20:52

Thank you! I'll post the files ASAP then!
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