Quickie Assembly Troubleshooting

[zimmermotor]

        Hi all. I just finished putting together my first quickie. It was my very first time soldering anything, and I thought I did a damn good job of it! However, when it came time to do the final voltage tests, I found, to my dismay, that the power from the 9v stack is not passing from the T3L terminal to the tubes. The assembly looks picture perfect, and all of the joints are nice and firm. I have no idea where I went wrong. My next step seems to be removing the caps and resistors and redoing them, but I'm not even sure how to do it safely. Any suggestions on where to look next? It was a lot of fun, but now fear is creeping in to the experience.

~Evan

[Len]

Is the other battery wire (negative or ground) soldered correctly?

[zimmermotor]

To the center lug on the switch, yes. The voltage between T3 and the center lug on the switch is over 38, but nothing between T3 and T2, T4 or ground.

[Len]

Did you turn it on? Are the filament circuits (1.5V) OK? Are the batteries in the right way?

The circuit will not be completed if the filaments aren't lit.

Also check the rest of the circuit. 4K resistors and 1K resistors. Those will complete the circuit for the 36V. But you will have had to do something wrong on both channels for neither of them to conduct.

[zimmermotor]

Yes and yes. Both tubes glow (in a very dark room), though one more than the other. As for the resistors, again, all of the joints are shiny, firm and isolated. Is it possible I'm not measuring the voltages correctly? 200V range, black lead to the ground buss wire...

[Len]

        I found, to my dismay, that the power from the 9v stack is not passing from the T3L terminal to the tubes.

Page 32 of the manual shows zero volts from T3 to ground, so that should be right.

Could you post the voltage readings you get against the readings on page 32 of the manual?

[zimmermotor]

Okay, now I'm really worried! I was getting wonky numbers, and after doing something so insignificant that I don't even know what it was, I'm now getting perfect numbers! Something is probably loose, isn't it.

[Len]

It's possible that the probes were not tight in the meter or something like that. Unless some wires were attached by not soldered, it's not very probable that there was the same loose connection on both channels.

You should check the terminals themselves, not the solder on the terminals. The solder could have a flux coating on it that can mess with the readings.

How does it sound?

[zimmermotor]

     Well, it sounds f-ing great! I wouldn't say that I've got it in an optimal set-up, what with the shoe-box chassis and fairly low-end components. However, being my first tube listening experience I was positively mystified! I was born post solid-state, so I had only heard about the "tube" sound till now.
   
For lack of a better source, I have it set up thusly...   Iphone line-out -> Quickie -> NUforce Icon Mobile -> Grado Sr80's.
   
My first surprise was how microphonic the tubes are (as well as how cool microphonics sound initially!). The second surprise was at how much better the bass extension and fullness are compared to just the iphone into the nuforce.
   
This fine piece will ultimately end up somehow stuffed into my car's center console with an imod to function as my system's primary head unit... There will be cutting and drilling I fear...  Thanks for the help!

[Len]

Glad you got it going. It seems it was fine from the beginning.

Cool about the car head unit. Some car interiors are very acoustic. I used to park my old Volvo 122S on the side of the road in summer and listen. It sounded better than my home system at the time.

[zimmermotor]

Hi again. So anyway, I have rebuilt the quickie in a new body with some new bits, (and brimar tubes, which sound excellent), yet I am still having a single issue which I think may just be normal. Whenever I turn the power on or off I get a loud pop. Pretty standard troubleshooting, I'm sure, but I don't really understand the circuit. Any ideas are appreciated. Thanks!

[Grainger49]

zimmermotor, the approved turn on sequence is to turn on tubed equipment from source to amplifier with a 30s delay in between.  That is, if you have a tubed source that is first, then the linestage, then the power amp(s).  As a matter of fact my SS Ack! dAck! does the same thing.  So I delay turning on my Foreplay by 30s.

Turn off sequence starts at the power amps and works backward.

[booangler]

Grainger, Is that the only solution to the popping issue. My wife forgets that there is a proper order to follow. I fear for my speakers when I hear the pop!

Thanks, Alan

[Grainger49]

The popping can be just annoying.  In my all Bottlehead system it doesn't harm anything, but my self respect if I don't turn it on the right way.  The noise hasn't moved my 94dBW speakers too hard or too far.

But... back in the 90s I had a modified PAS-3 and a SS power amp.  I left them on all the time.  One day there was a power outage, the power amp came back up quickly and when the PAS started to generate that DC leak (worse than a Foreplay), the power amp amplified it.  My Dynaudio woofers were smoked.  That was expensive!

So the results of the turn on can be anywhere from annoying, insulting, to destructive.  The other solution is a time delay relay that shorts the outputs till the voltages are stabilized.  The relay is not in the audio path it simply mutes the circuit then gets out.  There are some circuits described on the old forum.  An alternative is to unplug your speakers and leave a tag on the plug saying "do this last."

[Paul Joppa]

The problem with a time delay relay in the Quickie is how to power it without draining the batteries. Perhaps a separate battery pack for the relay? A quick look shows a few relays that need as little as 3 volts/50mA so a pair of D cells could last about twice as long as the filament batteries.

You could probably do a FET switch at the output with some time delay property. Most audiophiles are not fond of putting a solid state switch across the signal line on the grounds that it can damage the sonics, but such things have been used commercially.