Conqueror Fuzz

DeeBattery

New member
I'm new to understanding parts and parts numbers. The build calls for BC548 but can only find parts ending with A, B or C. Please educate me on the difference if there is one for this application. Thanks
 

Bricksnbeatles

Well-known member
From Wikipedia:

Gain groups​

The type number of any of the devices in this "family" may be followed by a letter, "A" to "C", indicating devices that have been selected that fall within a narrow range of gain (hFE). The same letters are used for this purpose in several other European transistors, and is similar in principle to the "Yellow", "Blue" (and so on) gain groupings in Japanese transistors, but should not be confused with the "A" suffix used with some American (JEDEC) devices, such as the 2N2222A, to indicate a variety of differences or enhancements over the base type.

The BC548 is available in three different gain groups:.

  • "A" indicates low gain (110 to 220, typically 180) at 2 mA collector current,
  • "B" indicates medium gain (200 to 450)
  • "C" indicates high gain (420 to 800)
So a BC548 might have a current gain anywhere between 110 and 800, but the gain of a BC548Awould be within the range of 110 to 220.
Pretty much, the letter refers to a general gain range for the transistor. I’m not sure what the ideal is for the Conqueror fuzz, but once someone else is able to chime in with that, you’ll know which you need!
 

mdc

Well-known member
The BC549C is pretty standard, low noise, and sounds excellent in most things so I'd probably start there. Tayda does offer an unsorted BC548 (no suffix) for even less, but I'm guessing that the circuit isn't super fussy about gain ranges.

If you already have 2N5088 NPNs on hand I'd just use those (but mind the pinout).

2N3904 NPNs and 2N3906 PNPs would also probably work just fine.

Socket the transistors and mess around, maybe you'll find some random/magical combo?
 

DeeBattery

New member
As for capacitors if this is a 9v powered unit then using 50v instead 9v would be overkill? I'm assuming that the size would also be bigger.
 

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Betty Wont

Well-known member
As for capacitors if this is a 9v powered unit then using 50v instead 9v would be overkill? I'm assuming that the size would also be bigger.
Use capacitors that are rated at least twice the supply voltage. In this case you would want 18 volt or higher rating. There is no disadvantage to using higher rated caps except the physical size does get bigger. Tayda and Mouse both list the physical sizes of their caps so you can see if they will fit.
 

DeeBattery

New member
1629237139354.png I've never soldered a inductor to a PCB before. I see that the primary should be facing up but do I solder all 6 leads and the 2 that hold it down?
 

Feral Feline

Well-known member
There was another thread with this question or similar. Ought to be a build-wiki.


My thinking is that it's a fairly large heavy component, relatively speaking. I'd want to lock it down so the critical leads that conduct signal aren't stressed and given a chance to crack.
 

Chuck D. Bones

Well-known member
The BC549C is pretty standard, low noise, and sounds excellent in most things so I'd probably start there. Tayda does offer an unsorted BC548 (no suffix) for even less, but I'm guessing that the circuit isn't super fussy about gain ranges.

If you already have 2N5088 NPNs on hand I'd just use those (but mind the pinout).

2N3904 NPNs and 2N3906 PNPs would also probably work just fine.

Socket the transistors and mess around, maybe you'll find some random/magical combo?
2N3906 is PNP and will not work in place of a BC548 or any other NPN transistor. BC549C is a good all-around sub for Si NPN transistors in most pedal circuits. A few work better with low-medium HFE transistors.

Feel free to swap transistors, but maintain the same polarity. Subbing Si for Ge or the other way 'round usually does not work unless you're willing to fiddle the bias resistors.
 

mdc

Well-known member
2N3906 is PNP and will not work in place of a BC548 or any other NPN transistor. BC549C is a good all-around sub for Si NPN transistors in most pedal circuits. A few work better with low-medium HFE transistors.

Feel free to swap transistors, but maintain the same polarity. Subbing Si for Ge or the other way 'round usually does not work unless you're willing to fiddle the bias resistors.
Doesn't the circuit use both NPN and PNP transistors?
 

Chuck D. Bones

Well-known member
Yes, but the original poster asked about BC548 and I wanted to make sure they knew that 2N3906 was not a sub for BC548.

As for Q4 and Q5, they are wired as back-to-back diodes, so in that case, either NPN or PNP will work. Some people substitute Ge transistors, Ge diodes or Si diodes. If you use Ge for Q4 & Q5, the output volume will be less.

They way this circuit is wired, Q3, Q6 & Q7 do nothing. Save yourself three transistors and a hand-full of R's & C's. Omit R10, R12, R13, R17-R19, C7, C16, Q3, Q6 & Q7. Jumper Q3 E to C. Jumper Q7 E-C. It works exactly the same except it draws less power.

If Jext Telez understood how the circuit works, they would have left those parts out. For reference, take a look at the Magical Mystery Box schematic and the Vox Conqueror preamp schematic.
 

DeeBattery

New member
From Wikipedia:

Pretty much, the letter refers to a general gain range for the transistor. I’m not sure what the ideal is for the Conqueror fuzz, but once someone else is able to chime in with that, you’ll know which you need!
Never soldered an inductor before. Does this look right?
 

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