Menatone Pig [traced]
I just used a multimeter on the NPN sideFiveseveN wrote:How are you measuring them?
- FiveseveN
- Cap Cooler
Information
Yeah, that's not going to tell you anything meaningful: it divides collector current by base current, but for FETs the "base current" is basically zero, they are voltage-controlled devices.
PS: here's a discussion about characterising JFETS: http://stompville.co.uk/?p=112
PS: here's a discussion about characterising JFETS: http://stompville.co.uk/?p=112
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)
- The Rotagilla
- Diode Debunker
Do you have a legit schematic of the Pig? I've never been able to find one.Dr Tony Balls wrote:sinner wrote:No, not me, not now. I'm quite bored with FX units recently, I'm sorry broagoldoor wrote:Anyone care to do a vero for this? Bee dot? Sinner?
I'm inches away from doing a turret board layout and build for a Marshall Pig...
The television will not be revolutionized.
- johnk
- Resistor Ronker
I just drew up a PCB for it and can confirm that the tagboard schematic has an error. the 22n that goes to lug 3 of the gain pot on Q4 should be connected to the DRAIN and NOT the source. It has much more gain that way. this was posted earlier in the thread.
here's my verified PCB layout and a PCB that is 800dpi:
here's my verified PCB layout and a PCB that is 800dpi:
- johnk
- Resistor Ronker
I tried these values in mine and the Jfets bias up A LOT better with them anf the circuit sounds much nicer. I din't find the need to replace R2 or R27 (the input and output resistors) but thanks for posting the info!The Rotagilla wrote:Bumping for some questions and new info.
I had access to a Pig built this year and had a question. Turret Board's schematic shows a 22nf going from Q4's source to Lug 3 of the Gain control. In the version I have, the 22nf seems to go from the drain to Lug 3 of the Volume control while there's an added 22uf to ground from Q4's source (in parallel with R19). I may very well be wrong, so please correct me if I am. Also the following changes were noted...
C12- 500p
C13 - Omitted
R2 - 33k
R5 - 27k
R15 - 33k
R18 - 33k
R21 - 33k
R25 - 33k
R27 - 10k
- johnk
- Resistor Ronker
update: i did find the pedal to sound a little dark so i replaced C18 (a 4n7) with a 3n3 and i like it a lot better now which is pretty much like having R27 being a 10K with the 4n7.
- The Rotagilla
- Diode Debunker
That's really sharp looking.johnk wrote:just finished boxing mine up. since it runs on 18V I added an internal charge pump and a relayed true bypass:
[ Image ]
The television will not be revolutionized.
Your pedal looks killer! Is the box design hand made with a Dremel? I'm sure it sounds on par with the look too.johnk wrote:just finished boxing mine up. since it runs on 18V I added an internal charge pump and a relayed true bypass:
[ Image ]
- johnk
- Resistor Ronker
sanfi4u wrote:Your pedal looks killer! Is the box design hand made with a Dremel? I'm sure it sounds on par with the look too.johnk wrote:just finished boxing mine up. since it runs on 18V I added an internal charge pump and a relayed true bypass:
[ Image ]
the pedal enclosure was etched with an etching solution.
hey there, i just built one of these with your board layout and it works great. just wondering (since you used the values the guy posted from a later unit with regard to drain values, etc.) did you leave in both 100pf caps or did you omit the one omitted that the guy posted? i'm asking because i have a high pitched whine that gets louder as i turn up the gain and/or the treb. controls. just wondered if you encountered this at all. i thought it might be the charge pump (type, grounding, etc.) but i don't think this is the case. btw, can you post the tagboard schematic----i see it alluded to in this thread but can't seem to find it. thanks rhjohnk wrote:update: i did find the pedal to sound a little dark so i replaced C18 (a 4n7) with a 3n3 and i like it a lot better now which is pretty much like having R27 being a 10K with the 4n7.
hey there, thanks for the reply. so all you changed in the end from your parts initially installed on your layout was just the drain resistor values and kept everything else as posted in the layout? rhjohnk wrote:I built it just like the PCB that I posted. mine has no issues at all.
cool thanks man. do you know what you set the 100k trimpot to? didn't have a trimmer that would fit so i just stuck in a 27k resistor, however the bass ch seems like it's not as loud as the treb ch so i was wondering about that. rhjohnk wrote:I actually ended up changing one of the 100pf caps to a 10pf for more top end:
- modman
- a d m i n
Information
- Posts: 4890
- Joined: 19 Jun 2007, 16:57
- Has thanked: 4394 times
- Been thanked: 2131 times
dude, nobody can tell you, because it depends on the particular characteristics of the jfet. alternatively, connect a similar value potentiometer to that spot, set the correct resistance by testing. the desolder the pot without changing the setting and measure it. then you know the resistor value to use with you particular setup.rhinson wrote:do you know what you set the 100k trimpot to? didn't have a trimmer that would fit so i just stuck in a 27k resistor, however the bass ch seems like it's not as loud as the treb ch so i was wondering about that. rh
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal