bad cat mini?

[chuckb]

Hey guys, I know this is a stuipid ? but on the bad cat mini schematic the pins are not numbered. I Know on the 12ax7 where 1 2&3 and 6 7 & 8 are .I know also the on the el84 that it's 2, 7, 9, & 3 but where #3 is there's a bent arrow,does this mean to join 3&8 together? Where does the cathode tie in? It shows that it ties in between #7 and #2 then goes to ground?

Chuck.badcat-minicat-amplifier-schematic[1].pdf

[chuckb]

Anyone?

[greekie]

It means that these two parts of the tube are internally connected.

Jake

[greekie]

Also, I wouldn't use 220K as a value for balancing the heaters. Use 2x100 ohm or 220 ohm. That works 99% of the time.

[chuckb]

Hey guys thanks for chimin in. I hear ya on the 220k for balancing the heaters.I have power and everything on but no sound.I'll change the 220k balancing the heaters for 2x100 ohm. So where the cathode ties in(220uf/250v with 220 ohm Resistor) to the el84,just above the pin#2 is this conection to pins 3&8?

[greekie]

Focus on getting sound before worrying about the heaters.

[chuckb]

Yes, I got sound but it's very intermittent. Any suggestions?

[chuckb]

I can only get sound when I hit the guitar strings really hard and then the sound is very weak. Could it be a grounding issue?

[loudthud]

There is a mistake on the schematic. The right side (on the schematic) of the Master Volume pot that connects to the 220K resistor should also go to ground. The 220 ohm resistor that connects to pin 3 of the EL84 should be atleast a 3 watt part.

Voltages on the EL84 should be:
Pin 2: 0V
Pin 3: 10.4V
Pin 4: 3.15VAC
Pin 5: 3.15VAC
Pin 7: 312V
Pin 9: 320V

[chuckb]

Hey loudthud, thanks man. That was my problem,the 220k resistor wasn't grounded. I changed the 220 ohm resister on pin 3 to a higher wattage as you suggested and the amp is now working pretty good. Thanks again for your help,I appreciate it.


Chuck.