Seiche wrote:Manfred, when did the resistor 470k on Q3s gate appear? It's not in the tagboardlayout or the other schematic.
IMO the resistor is essential for biasing the FET Q3.
that's surprising, because the tagboardlayout is verified, I understand.
Seiche wrote:that's very interesting. Which program are you using?
Seiche wrote:I think Volume and Treble should be 50kA and Drive and Voice should be 50kB.
modman wrote:However, have a look at C14 in the old one: there is written "100k = 10pF", other schematic has this value as 100pF, don't know where that came from.
Maybe the solution the capacitor has 100k written on it, meaning 100,000 (pF) = 100nF? [...] if you have the unit in front of you, how could you have to guess?
Seiche wrote:I don't think a 470k is needed.
I'm guessing it is one of those orange ones and in reality 100K = 10pF and the person tracing it has not seen one of those before.
I going to order some 2N5952s for making real trials.
I'm not using 2N1308, I'm using MP38A, I don't know if that makes a difference, the MP38A are very low leakage.
I'm pretty sure 100 = 10*10^0=10pF.
Also Manfred is taking the output from the source, whereas the original circuit has the 1uF and output connected to the drain of Q3. Manfred, could you repeat your simulation for both? I don't think a 470k is needed.
I've included the 470k in my build and while there is not much difference in volume (it's still too loud, how would you propose to reduce gain?), there is more treble and clarity
Manfred wrote:Sorry, I had that overlooked that, but I think it is solved.
Also Manfred is taking the output from the source, whereas the original circuit has the 1uF and output connected to the drain of Q3. Manfred, could you repeat your simulation for both? I don't think a 470k is needed.
Also Manfred is taking the output from the source, whereas the original circuit has the 1uF and output connected to the drain of Q3. Manfred, could you repeat your simulation for both? I don't think a 470k is needed.
(it's still too loud, how would you propose to reduce gain?)
Seiche wrote:hm sounds better without the 470k to me![]()
I have also upped the 2k to 20k, but I think it should be increased even more (maybe also the 8k2)
Return to Boutique Stompboxes dissected...