Hot Cat Bad Cat finished, build ?

[chuckb]

Hey guys, I have just finished a Hot Cat Bad cat build and I'm having some problems. Both ch are working good except that I'm getting alot of vol/gain on the clean ch which only consist of a vol and brilliance and only uses one side of the first tube.. The Gain ch has , Gain,Edge,Level,Bass,Treble, and Mv. Everything works fine on this ch but it's lacking vol/gain compared to the clean ch. It almost seems like the Clean ch should be the Gain ch and visa-versa. Any help here would be greatly appreciated.

Chuck.

[chuckb]

hot cat bad cat schematic.

Hey guys, here is the schematic I'm using in my build.

Chuck.

[chuckb]

Hey guys, anyone out there got any ideas on what might be the problem i'm having with this build?

Thanks,
Chuck.

[Jag]

Did you review Loudthud's partial schematic redraw in your other thread on this? You NEED make those changes. Especially the switch of the 1M and 5M1 resistors.

[chuckb]

Hey jag, yes I made those changes the loudthud provided me. I swithced the placing of 1M and 5M1 putting the 1M before the 100n cap and the 5M1 after the 100n cap on the input,also grounded the gain input. I also made the changes to the MV that he also suggested. I have loads of vol on the clean ch and when turned up I get nice breakup. The gain ch on the other hand is lacking the same punch in vol with very little breakup. All the eq works fine on the gain ch but no vol like on the clean. The amp sounds great on the clean ch,real rich,but I want to be able to have that overdrive of the gain ch as well. I had the day off and been working on it all day trying different things. The schematic shows that the cathode on V1a has no resistor or cap. I just tied the pin 8 cathode to ground with no resistor or bypass cap. I did try a 1.5 resistor and a 22uf/50v bypass cap there but put it back to original. Any other suggestions would be greatly appreciated.

Chuck.

[chuckb]

Hey guys , anyone else have any suggestions,I'm starting to pull my hair out trying to figure what the problem is,LOL.

Chuck.

[Chuck H]

There are just too many things it could be for anyone to answer. You should do a full voltage check and signal trace. That will probably show YOU where the problem is or at least give US some info to work with.

Chuck

[loudthud]

If you can't get any overdrive through the lead channel, there must be a wiring mistake, wrong resistor, defective capacitor, or something like that. Voltage checks on all tube pins might give us a clue and sometimes good clear pictures can reveal things to "Fresh eyes". If you made some kind of mistake, it's difficult for you to see it, but it might be obvious to anyone else Check any resistor by measuring across it in circuit. If it measures too high, it's probably the wrong value or defective. If it measures too low when connected to the circuit, unsolder one end and measue again.

[chuckb]

I changed out the 56k cathode resistor on V3a to a 100k,change the volume pot to 1Meg and removed the 220k resistor from the Master volume and I got overdrive now. It's much better but the volume is not as loud as the clean ch though. I went over every resistor today and did measurments on them,having to remove some of them to get a accurate measurement.They all were fine. I'll check out the caps tomorrow and do the voltage checks on all the tube pins as well. I'll post the voltages when I get them. Thanks again and I'll talk to you tomorrow.

Chuck.

[chuckb]

Hey Loudthud,
I did the measurements on the tubes and here are some of my readings.
PINS.
V1= 1 @ 103.9v
3 @ 0v
6 @ 141.7v
8 @ 1.13v

V2= 1 @ 223v
3 @ 1.62v
6 @ 144v
8 @ 1.09v

V3= 1 @ 327v
3 @ 208.3v
6 @ 201.2v
8 @ 1.35v

V4= 1 @235.1v
3 @ 63.8v
6 @ 237v
8 @ 64.1

V5= 3 @ 356v
4 @ 354v
5 @ 20v

V6= 3 @ 356v
4 @ 356v
5 @ 20v

Rec= 4&6 @ 334v
2&8 @ 361.9v

There seems to be a high voltage on pin3 of V3 & V4 as compared to the rest of them.Also pin8 of V4 seems high as well compared to the rest . I still have alot more volume on the clean channel then i have on the gain channel though. I would post pics of the amp but i don't have a digital camera right now ,mine took a swim.

Chuck.

[loudthud]

Those voltages look good to me and they agree with the schematic. The pin 3 voltages on V3 and V4 are normal for the circuits that are used.

The component values on the schematic are in an unusual format. The purpose of the format is to get rid of decimal points which tend to disappear. This many times confuses even us old guys. So just to make sure you haven't made a mistake, 5M1=5.1Megohms, 1k5=1.5k=1500 ohms, 1M5=1.5Megohms, 1n5=.0015uF=1500pF, 10n=0.01uF, 100n=0.1uF, 22n=0.022uF.

Beyond that, try disconnecting one end of any cap that goes to ground in the lead channel except the 22uF and 33uF filter caps. There is a chance one of those is killing the signal. Next, check the pin numbers you assigned to the 12AX7 tubes. They should go top to bottom 1, 2, 3 or 6, 7, 8 except V4b which is upsidedown.

I'm running out of ideas here. Disconnect point F from the Master volume pot. Run a temporary wire from point F to pin 1 or pin 6 of the 12AX7s in the lead channel. The signal should get progressively louder as you move from left to right on the schematic.

[chuckb]

Hey loudthud,
I have all the component values right as in the schematic except for the Bass pot where I have a 1meg pot. I'll check any caps(except the 33uf and the 22uf's) going to ground and disconect them to see if thta makes any difference. I'll let you know how things work out. Thanks again.

Chuck.

[chuckb]

Hey Loudthud,
I removed the 360p cap going to groung from V2a and the vol problem is solved. Thanks so much for your help with this I really appreciate it.

Chuck.