gUITAR gADGETS bmp MUFF CLONE

[REGNAD]

the parts layout from GGG shows the caps oriented the other way... is this a typo? also, c13's cap doesnt show a pos or neg marking on it. i'll check for shorts around r5.
regnad

[REGNAD]

ok, i had an 820 ohm resistor in r5. i have replaced r5 with the correct value resistor but still have 8.03 vdc on the collector and .867 vdc on the emitter and 1.38 vdc on the base of q1. I couldnt fully test the sound (wife watching movie) i could hear more distortion but the voltages still look wack. What do you guys think?
regnad

[REGNAD]

ok, i just tried the muff again, its working now, but im not sure if all the way. i say that because of the voltages i still have on q1. should i have 4-5 vdc on all collectors? i only dropped like one volt on the collector when i replaced r5 with the correct resistor. will i get more distortion if i increase the r5 value until im at 4-5 vdc on q1 collector? if so, why am i having to increase so much from the kit value?
lot of questions , i know.

updated values:


1. seems to work but hardly any distortion at all
2. GGG BMP kit (rams head)
3. http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=108&Itemid=26        then choose rams head version
4. no mods
5. no subs
6. no power conversions, just GGG stock
7. Batt voltage = 9.33 vdc
8. Voltage at the circuit board end of the red battery lead = 9.29 vdc
9. Voltage at the circuit board end of the black battery lead = 0.00 vdc


new q1 values listed second

Q1
C = 9.18 VDC-----8.02 vdc
B = 1.56 VDC-----1.388 vdc
E = 1.04 VDC-----.865 vdc

Q2
C= 4.02 VDC
B= .63 VDC
E= .06 VDC

Q3
C= 3.72 VDC
B= .60 VDC
E= .03 VDC

Q4
C= 4.02 VDC
B= 1.68 VDC
E= 1.13 VDC


D1
A (anode, the non-band end) = .52 VDC
K (cathode, the banded end) = .63 VDC

D2
A = .63 VDC
K = .52 VDC

D3
A = .49 VDC 
K = .60 VDC

D4
A = .60 VDC
K = .49 VDC



caps metered while on pcb

C14 HAS 9.2 vdc on the posative side and 0.00 vdc on the negative side

c1 HAS less than 1 volt but it drops on the positive side and 1.52 steady on the negative side<-----i understand this is bad

[slacker]

the parts layout from GGG shows the caps oriented the other way... is this a typo? also, c13's cap doesnt show a pos or neg marking on it.

The layout pdf shows C1 oriented the same way as the schematic which is incorrect. The bill of materials says C9 and C13 can be film caps in which case they aren't polarised so they can go in any way round.

will i get more distortion if i increase the r5 value until im at 4-5 vdc on q1 collector? if so, why am i having to increase so much from the kit value?

You shouldn't have to change any of the values to get it to work, some circuits might need changes making for different transistor but the Big Muff will work fine if built with the values off the schematic.

You've still got a problem with Q1. The fact that changing R5 changes the voltage means there isn't a short there so either theres another incorrect resistor value round there somewhere or a bad connection.
The rest of the transistor voltages look fine, so once you figure out what's wrong with Q1 you should be in fuzz heaven

[REGNAD]

ok i just noticed that there are "errors" in the GGG rams head plans. are these causing my q1 problem?
i installed the values speced from the bill of materials. but the values from the bill of materials arnt the same as the values on the schem and device layout for r2, r8, and r13.
r8 and r13 are close but r2 is a big difference!!


update....
i have replaced the r2 and r4 resistor to 47k and 120 ohm per schematic instead of bill of materials. i also flipped polarity of the c1 cap per your direction. i now have 6.6 vdc @ the q1 collector and MUCH more distortion. i have not replaced r8 and r13 with correct values (per schem) yet but will.  i feel this pedal is now correct, falty bill of materials and my inability to see colors corectlly @ 2am is the final reason for problems. I cant blame anyone but myself for my errors but im a little anoyed that this kit had inacuracies. I mean, thats why i bought a kit, so i didnt have to worry about having the wrong parts. i couldnt find a 47k resistor in the kit.... Long story short, i probably wont purchase another kit if this is the norm.

i will swap the last resistors and chime back in...
Thank you Slacker, you where very helpful!
regnad

[petemoore]

Q1
C = 9.18 VDC-----8.02 vdc
B = 1.56 VDC-----1.388 vdc
E = 1.04 VDC-----.865 vdc
  So Q1 is now biased ?

Q2
C= 4.02 VDC
B= .63 VDC
E= .06 VDC

Q3
C= 3.72 VDC
B= .60 VDC
E= .03 VDC

Q4
C= 4.02 VDC
B= 1.68 VDC
E= 1.13 VDC

[REGNAD]

so what does it mean to be biased? Its nice and "muffy" now. i wil post current voltages soon. Q!'s collector is now around 6.6 vdc.
regnad

[REGNAD]

well, i did an A/B comparison of my ramshead clone and it sounds just like a little big muff. Should it? I have never heard a ramshead before, i was expecting something different. My clone was slightly briter otherwise the same.
regnad

[bumblebee]

the new little big muff is very similar to the rams head,yes.

[REGNAD]

ok, how does the triangle and cival war models compare to the rams head?