Tode Resistance / Voltage errors

[Bill Chase]

After touching up some suspect joints, I went back and rechecked all of my wiring (appears to be correct), and rechecked my resistance and voltage checks with a few discrepancies:

Resistance:
   Term 16, and A7 & A9 should be *, I have 0
   B3 should be 150 ohms, I have *
   B4, B5, A4, A5 should read ~0, I have *

Voltage: 
   Back chassis term 11 should read 325v, I have 384v
   Front chassis term 2 should be 35v, I have 15v
                     term 5 should be 37v, I have 20v
                     term 10 should be 36v, I have 15.3
                     term 11 should be 325v, I have 386v
                     term 12 should be 293v, I have 366v
                     term 22 should be 295v, I have 367v
                     term 24 should be 30v, I have 5.5v
                     term 25 should be 4v, I have 1.4v

The LED works, and I have EL84 (A socket) tube glow, but none from the EF86 (B socket), and no sound.  Term 16 is where the center conductor of the coax connects to the B9, and my other discrepancies are connected to the EF86 socket, so I think I need to re-verify I've got the EF86 section wired right.  I'm fried for tonight, so I'll have to re-attack it tomorrow.

 

[Doc B.]

re term 16, make sure the center conductor isn't shorted to the outer braid.

A7,A9. These are the plate and screen of the EL84. Most definitely should not read 0 ohms, and your voltage measurements tend to indicate that they are probably not shorted.

re B3, does B8 read 150 ohms? if it does, then B3 does not have continuity with B8. If they both read infinite then there might be a bad joint at one end or the other of the 150 ohm resistor connected to B8 and B7.

B4/5, A4/5 are heater connections. The center tap of the heater winding is terminal 10 on the power transformer, which connects to 6U on the t-strip mounted on the power transformer, then to the ground lug on the IEC socket, then to the chassis ground lug. Check all of those connections.

EF86s don't glow much at all because of the internal shield

[Bill Chase]

Doc,
    Fixed!  I removed and replaced the 4" coax wire after touching up joints and still having the problem. Given your guidance on the checking the outer braid, it seemed the most likely place to have missed something.  It appears I did have a undetected short the first time around, as everything worked great after replacing it!
    Many thanks for the troubleshooting and another great kit!  It's late, so I can't play much w/o risking waking up the kids even with an acoustic/electric uke & headphones.  I can't wait to plug in the electric guitar in the morning!
Cheers,
Bill

[Doc B.]

Woo Hoo! Looks very cool! Let us know how it sounds.

By the way if you have a solid body electric that it doesn't intrude too much into the environment itself, closed back headphones are great with the amp. I use ATH-A900s. 

[Bill Chase]

   I had some time this weekend to play with the amp see how it sounds.  I have an acoustic electric classical guitar and ukulele that both sound fantastic played clean through the Tode.  I love the sound of the EL84 with my acoustic instruments-- tone is full, clear, & warm, projects extremely well. 
   With the electric guitar, the Tode is extremely versatile.  I really enjoyed experimenting with the Midscoop and being able to switch up the tone while keeping the underlying richness.  I was able to get an amazing range of distortion between my guitar's controls and the crunch setting on the amp.  Between the sound and the satisfaction of building it, this amp is simply AWESOME!  Thanks for another great kit!!
Cheers,
Bill

[Doc B.]

Wow, thanks Bill! It's always tough for me to promote a new product. I get enthused and then I hope like h**l that others might feel the same way. Really feels good to hear that your impression of Tode is the same that I had when we first put it together.