No sound, no tubes lighting up - did resistance checks

[Paul Birkeland]

nt

 

[drewhaynes]

Oh my... you guys' patience for my incompetence is astounding. I have been, in fact, measuring at the 1 through 10 terminals on the TRANSFORMER, which are marked 1-10 on the transformer itself. Let me retest.  :-[

 

[drewhaynes]

Wow. New readings:

1 = 85V
2 = 169V
3 = 0V
4 = 169V
5 = 85V
6 = 0V
7 = 107V
9 = 110V
10= 0V

How do those look? And is it a concern or will it have an audible impact where I am seeing that 7 and 9 are assymmetrical, whereas 2 and 4 are symmetrical?

 

[Paul Birkeland]

1 = 85V
2 = 169V
3 = 0V
4 = 169V
5 = 85V
6 = 0V
7 = 107V
9 = 110V
10= 0V

That's a working amplifier.

How do those look? And is it a concern or will it have an audible impact where I am seeing that 7 and 9 are assymmetrical, whereas 2 and 4 are symmetrical?

2 and 4 are wired together and are simply the raw B+ voltage available in the power supply.  They will always match perfectly.  7 and 9 are the cathodes of the 6080, which will vary a bit depending on both the 12AU7 and the 6080.  The difference of a couple of volts on those terminals will be inaudible. 

On the other hand, if your voltages at 1 or 5 happen to pop up above 100V, that can indicate an operational issue with the amplifier or a 12AU7 that's getting weak.

 

[drewhaynes]

Oh man, I'm excited. So I'm safe to plug in my HD650's now?

If this amp is as good as I remember, I may need to sell my Denon D2000, Hifiman HE400, and O2 amplifier and get a Speedball and some other high impedance headphones.... Beyer DT880/990 600ohms? AH! Again, I'm excited. I also have a Sylvania 5814A tube... no idea how much that affects the sound.

I am SO SO SO appreciative of all the help... if you ever end up in Tulsa, OK, I owe you *cases* of beer.

 

[Paul Birkeland]

As long as there's 0V at terminals 6 and 10, you're good to go. 

Though the voltages are spot on, if you have other solder joints that aren't quite solid you may notice that the amp is a bit noisy or just doesn't sound right, but those are easy problems to go after since everything is working.

-PB

 

[attmci]

Oh man, I'm excited. So I'm safe to plug in my HD650's now?

If this amp is as good as I remember, I may need to sell my Denon D2000, Hifiman HE400, and O2 amplifier and get a Speedball and some other high impedance headphones.... Beyer DT880/990 600ohms? AH! Again, I'm excited. I also have a Sylvania 5814A tube... no idea how much that affects the sound.

I am SO SO SO appreciative of all the help... if you ever end up in Tulsa, OK, I owe you *cases* of beer.

Always use a "sacrifice" headphone to test new tubes, caps etc.

 

[drewhaynes]

Well I've been listening with my HD650s tonight... so far so good. It sounds incredible, as good as I remembered or better. Definitely seems better than my O2 amp. I'm in love.

 

[attmci]

Well I've been listening with my HD650s tonight... so far so good. It sounds incredible, as good as I remembered or better. Definitely seems better than my O2 amp. I'm in love.

Welcome to tube rolling, then. LOL

 

[drewhaynes]

Seriously, the crack is incredible. I'm not sure how I lived without it all these years. Is the speedball worth it? I'm tempted to sell my Denon D2000 and Hifiman HE400 and O2 amplifier and do the speedball and maybe another pair of high impedance cans.... maybe DT880 600ohm.

 

[Deluk]

Looks like you've crossed the finishing line OK. Been away for a few days and was going to say that the soldering on the reply #43 looked under heated and with poor flow. Some on the tag strip connections hadn't flowed through at all.

 

[drewhaynes]

Looks like you've crossed the finishing line OK. Been away for a few days and was going to say that the soldering on the reply #43 looked under heated and with poor flow. Some on the tag strip connections hadn't flowed through at all.

I listened for quite a while last night - loveee it. That's good info above - maybe next weekend I'll open it back up and try to touch up a lot of solder joints - I'm certainly not a soldering pro, and using a cheapo iron. The only other things I've made are a CMOY amp and a Grubdac (not sure if I should explore other DACs maybe now that the Crack is alive again).

 

[Deluk]

If your solder iron is basic with no temp adjustment, hopefully not on of the "pistol" types, make sure the tip is cleaned properly and well tinned. If dirty it will not take on a smooth solder surface and be patchy with scruffy black sections. Keep tip clean and wipe it on a wet sponge (ionised/distilled water) or a mesh cleaner. Add a touch of new solder and press the tip against the joint until the solder flows, then feed in the solder as needed. Solder that is a bit too thin is better than too thick stuff as it gives more control, especially on boards. Don't cook the joint, but remove the tip quickly when the joint looks smooth and clean. Don't go over it again and try and smudge the joint! Should be quick, hot and accurate. Practice on an old board. This maybe your third amp but we all tend to do the same mistakes over and over again until that eureka moment.
If you need them there a several good soldering how to's on YouTube, some are better than others!