
beedotman wrote:NKT275 sounds great in MKII!
iq01221 wrote:Put it first in the chain, just after the guitar. The cause of the problem are the buffers cointained in the tuner, wah and the wahmmy.
Best regards!!
Masuto wrote:Hi Electric Warrior, Beedotman, Jamonslamon, and fellas, it's tonebender mkii building time again!
A friend of mine, whom i gifted with my very first oc75 build, was recently recording at a very nice local studio, and guess what, the engineer was stunned at the pedal. Pure violence, he said. So i decided to build some more. That was a perfboard build, now i mainly go for the Electric Warrior vero layout. I also won a huge ebay auction and some funny valvos (oc74, oc77, oc79..) are on the way. In the meantime, i got to really listen close to the differences between my oc84 and oc75 builds.. The oc84 is somewhat very 'coherent', as in steady, nice mids, great for rhythm guitar.. Whereas..well.. 'The oc75 SINGS. It breaks up in a wholesome lyrical, gracious way, a nice way to trail those notes to an end.. I am afraid to say it, but it appears that oc75's, those bastard expensive threesomes, are the go to trannies for this pedal. But lets wait till i get those valvos in, and i'll report.
Always a great read, fellows.
copachino wrote:
at min:
Q1:-8.38V
Q2:-0.589V
Q3:-7.7v
at max gain:
Q1:-8.38V
Q2:-0.4V
Q3:-7.73v
but im not so sure about Q3, it has already a 2,2Kresistor on it
LucifersTrip wrote:copachino wrote:
at min:
Q1:-8.38V
Q2:-0.589V
Q3:-7.7v
at max gain:
Q1:-8.38V
Q2:-0.4V
Q3:-7.73v
but im not so sure about Q3, it has already a 2,2Kresistor on it
I believe that's the problem. if you alter (lower) the resistor (8.2K) on Q3 collector too much, you will make it more boomy. you can get away with maybe 2K up or down from 8.2K, but not 2.2K. Just alter the resistor on Q2 instead. If you can't get what you like by altering that (and possibly tweaking Q1's base resistor for gain), then try different transistors or flip them around and try a different order.
copachino wrote:LucifersTrip wrote:copachino wrote:
at min:
Q1:-8.38V
Q2:-0.589V
Q3:-7.7v
at max gain:
Q1:-8.38V
Q2:-0.4V
Q3:-7.73v
but im not so sure about Q3, it has already a 2,2Kresistor on it
I believe that's the problem. if you alter (lower) the resistor (8.2K) on Q3 collector too much, you will make it more boomy. you can get away with maybe 2K up or down from 8.2K, but not 2.2K. Just alter the resistor on Q2 instead. If you can't get what you like by altering that (and possibly tweaking Q1's base resistor for gain), then try different transistors or flip them around and try a different order.
i only order a set from small bears(the last they have) but i will try with some resistors on Q2 maybe 60k on Q2 collector, also, do you think by lowering the bypass on q2 and q3 with help??, its on stock 100k maybe 82k or so,
copachino wrote:i tried a 33k first but q3 voltages was lower, so i used 47k(stock mkII) and q3 got about 8.5V now, so maybe i can increase the Q3 collector up to 6k and maybe a bigger resistor on Q2 will mae things better, but was talking also the bypass(not so sure how to call it) in te Q3 Emiter and Q2 base that its a 100k i remember that from small bear diagram that resistor was 47K(not so sure why), but i decided not to used since Q3 collector was aim to -4.5V and you guys told that Q3 has a bigger value, im sure that i need to lower Q2 a bit more almost at -0.2v or so
DrNomis wrote:copachino wrote:i tried a 33k first but q3 voltages was lower, so i used 47k(stock mkII) and q3 got about 8.5V now, so maybe i can increase the Q3 collector up to 6k and maybe a bigger resistor on Q2 will mae things better, but was talking also the bypass(not so sure how to call it) in te Q3 Emiter and Q2 base that its a 100k i remember that from small bear diagram that resistor was 47K(not so sure why), but i decided not to used since Q3 collector was aim to -4.5V and you guys told that Q3 has a bigger value, im sure that i need to lower Q2 a bit more almost at -0.2v or so
That 100k resistor going from Q3's emitter to Q2's base is what's called a "Negative-Feedback" resistor, it's job is basically to tame the huge gain of the Mk II circuit when the Attack control (1k B pot) is set to minimum, when you increase the Attack control the 4u7 (5uF) cap going from the wiper to ground gradually shunts the negative feedback signal to ground, thus letting the circuit operate with more gain.....
copachino wrote:my god friend can you tell me where to get a set of 0c75??, i have a generic from small bear but im not so sure, i have tried biasing but, still something just not right, the pedal has a great gain but somehow, sounds a bit darker ansd has more bass than thew original sound
i have measssure, and here are my voltages on max and min gain
at min:
Q1:-8.38V
Q2:-0.589V
Q3:-7.7v
at max gain:
Q1:-8.38V
Q2:-0.4V
Q3:-7.73v
im using -9.38V .... still sound like to much bass, i think it has a good sound but i has to much lows, sounds like too dark, and the vintage unit sounds more sharp, perhaps i have to lower even more Q2, and upper Q3??, but im not so sure about Q3, it has already a 2,2Kresistor on it, so i dont want to get damage
copachino wrote:i tried a 33k first but q3 voltages was lower, so i used 47k(stock mkII) and q3 got about 8.5V now,
Electric Warrior wrote:Not sure if they tell you that it needs to be 4.5V, but users here and an other forums have told me several times that their sets do measure 4.5V on Q3's collector with the supplied resistor values.
The schematic they use isn't correct either. It has a 100k on Q1's base and a 47k on Q2's collector instead of 10k/47k (OC75 version) or 100k/100k (OC81D version).
The range of hfes that come in their sets is really wide. I guess that doesn't make things easier.
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