Catalinbread - Dirty Little Secret [traced]
- loylo
- Breadboard Brother
Which multimeter do you use?
There is a huge difference between your readings and the theoretical resistors' values, according to their colour codes.
They have both 5% tolerance, so the first CC one shouldn't read lower than 950R and the second one 640R...
There is a huge difference between your readings and the theoretical resistors' values, according to their colour codes.
They have both 5% tolerance, so the first CC one shouldn't read lower than 950R and the second one 640R...
- pietro_moog
- Breadboard Brother
it's a cheap multimeter, like everybody else have. it's precise for all the other stuff.
- loylo
- Breadboard Brother
OK.
I asked because I used to have a very cheap multimeter (less than 3€/5$).
Until I realised all my readings were rather wrong (especially while measuring tube amp transformers).
So I bought a better one, anyway at a reasonnable price (around 30€/50$), which is very accurate.
I asked because I used to have a very cheap multimeter (less than 3€/5$).
Until I realised all my readings were rather wrong (especially while measuring tube amp transformers).
So I bought a better one, anyway at a reasonnable price (around 30€/50$), which is very accurate.
- Ice-9
- Degoop Doctor
Information
+1 on lifting the leg to read a resistor. You will not get an accurate reading with the resistor in circuit. Either lift one leg of the component free of the circuit and read with a meter or better still read the colour codes on the resistor.Ripdivot wrote:Best thing to do is just lift one leg of each component before you measure it and even your "cheap" meter should be pretty close.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !
No silicon heaven ? preposterous ! Where would all the calculators go ?
No silicon heaven ? preposterous ! Where would all the calculators go ?
- pietro_moog
- Breadboard Brother
the schematic is good, the values are ok. we definitely are ready for a vero layout. are you working on one?
- roseblood11
- Tube Twister
Are all other resitor values definitely verified by reading the color codes? You can't measure parts values in circuit, unless you're dead certain that there's nothing in parallel...pietro_moog wrote:the schematic is good, the values are ok.
- pietro_moog
- Breadboard Brother
yes, color codes are real.
i can't remove the resistors from the circuit. those traces are very tiny and the CC resistors legs are big, there is a big risk of damaging the pcb.
i can't remove the resistors from the circuit. those traces are very tiny and the CC resistors legs are big, there is a big risk of damaging the pcb.
Sure it can- you just can't be sure it'll sound exactly the same.
By adjusting the gain control, source resistors and bypass caps you should be able to get the same sound, more or less.
We don't know what they're doing to build them- they might be selecting transistors of specific gains anyway. My guess is no but it's possible.
jamie
By adjusting the gain control, source resistors and bypass caps you should be able to get the same sound, more or less.
We don't know what they're doing to build them- they might be selecting transistors of specific gains anyway. My guess is no but it's possible.
jamie
- roseblood11
- Tube Twister
Uwe stocked the MPF 4393:
http://uk-electronic.de/onlineshop/prod ... df4c9f94b8
But his link to the datasheet doesn't work. I guess it's this one, but it's possible that he sells transistors from another manufacturer...
http://pdf1.alldatasheet.net/datasheet- ... F4393.html
http://uk-electronic.de/onlineshop/prod ... df4c9f94b8
But his link to the datasheet doesn't work. I guess it's this one, but it's possible that he sells transistors from another manufacturer...
http://pdf1.alldatasheet.net/datasheet- ... F4393.html
- mmolteratx
- Degoop Doctor
Nic has stated that they select FETs before, IIRC. Dunno what parameter they select for in particular, but my guess is pinch off voltage.imaradiostar wrote:Sure it can- you just can't be sure it'll sound exactly the same.
By adjusting the gain control, source resistors and bypass caps you should be able to get the same sound, more or less.
We don't know what they're doing to build them- they might be selecting transistors of specific gains anyway. My guess is no but it's possible.
jamie
Once the schematic is verified, it might be nice if pietro_moog could post the voltages of the original one so we can compare the two. I never checked the voltages on any other of my Catalinbread builds so I don't think it matters that much.
- pietro_moog
- Breadboard Brother
the schematic IS verified. unfortunately i sold the pedal, i can not do any more check