COTS Power Supplies for Quickie

[minodev]

I'm a total noob. I didn't even build my Quickie. I bought it built. I know how to use a soldering iron, but that's where it ends.

Like many Quickie owners, I'd like to figure out a way to run it off AC. Unlike most people who contribute to this forum, I haven't the bloodiest idea how to build one. So I'm looking for Commercial Off The Shelf (COTS) options. Before I spend a bunch of cash on power supplies and likely burn up my beloved Quickie trying them out, I thought I should ask if anyone has any recommendations.

I gather I will need multiple COTS PSs because stepping up/down DC voltage is beyond me. Also, I'm in the USA, so I'll need to stick with 110v-compatible PSs. So I figure I will need:

- A 36v PS to replace the four 9v cells. Any recommendations?
- Two 1.5v PSs to replace the 2 D cells (I read that they "float," so I can't use one 3v PS). Again, any recommendations?

So this flows into a million questions:

1. Do I need to look for something special in a COTS power supply? Does it need to be "regulated" in order to provide clean power? It seems like noise is an issue in other posts about AC PSs. Any way to mitigate this issue?
2. Do I need to add a fuse somewhere if I use an AC PS?
3. For the 36v, there are lots of Kodak 36v printer PSs on ebay. Would these work? I also see 36v LED transformers a lot. Would these work?
4. Am I right that I need two separate 1.5v PSs to replace the D cells (without engineering something)?
5. Would standard "wall wart" style PSs work for the 1.5v?
6. I read somewhere that sharing the 1.5v grounds with the 36v supply won't work. Will this be a problem with separate AC supplies? If so, I guess I could suffer keeping the D cells and just using a 36v AC supply.
7. What kind of amp capacity do I need for the 36v? for each 1.5v?

And here's a very important question that I just can't work around:  if I've got a COTS power supply, how do I determine the polarity of the DC outputs? I've fried things before by reversing the polarity, and I don't want to do that to my Quickie.

Please don't answer in Alien. I won't understand. Everybody's a beginner at some point, right? I appreciate any advice the community can offer.

P.S. Caucasian Blackplate's topic "Prototype - AC powered Quickie" would seem to be helpful, but the picture links are all broken. I'd love to see what those pictures were.

[Paul Joppa]

Yes, you would want regulated, filtered outputs. Radio Shack sells a wide line, including 1.5v and 30v outputs.
The required minimum current capacity is 100mA for each 1.5v supply, and about 4mA for the 30v supply.

You won't find much above 30vDC, but that's fine; 30v is enough because the four 9-v batteries are down to 6v each before them need to be replaced. Also, most supplies will produce a higher voltage if the current draw is low - and 4mA is very, very low.

Be aware that even regulated, filtered wall warts may have some noise. It's going to vary between different models, and may or may not be audible.

[earwaxxer]

Paul is being nice here, but for the love of Pete - let the Quickie live on good clean battery power! She's an 'inside dog'. She is not used to that kind of 'mainstream' pressure! I'm kidding of course, but you can have SO much more fun with the batteries. Most of us are trying to get our A/C SMPS stuff OFF of mains on on to battery.

[porcupunctis]

Look for an old HP 6205 dual power supply.  For just a little more than the wallwarts you will have nice regulated power Plus you can use it as a universal PS for experimentation.

These things were built like tanks.  Your grandkids will be using it someday.

[minodev]

Thank you all for your input, especially Paul. That is really helpful info. I didn't realize the amp draw on the 36v was so low, nor that the Quickie was so tolerant of voltage variations. That really opens up the possibilities.

I do totally get the desire to run off batteries. They're perfect for most of my listening, which is a few hours at a clip. I can also see the value of investing in a 6205. But my specific challenge has both portability and endurance requirements that eschew these options:  I have a bad (good) habit of sneaking off with some audiophile buddies and doing an all-vinyl, 48-hour, high volume bender. The Quickie does a nice job of bringing out midrange detail and reducing listening fatigue. But speaking of fatigue, I tend to fade a little earlier than my buddies, and sunrise inevitably arrives with rather expensive set of formerly 9v paper weights cuz no one bothered to turn it off my Quickie before passing out.

I may yet explore some rechargeable battery options before diving headlong into AC supplies. But before I put this topic to bed, is it true that I would need 2 separate 1.5v power supplies to replace the D cells?

Also, I have an as-of-yet-uninstalled PJCCS kit. If running off of AC power, is the PJCCS a good idea?

[4krow]

I would think that the PJJS with AC power supply would not be a good idea. It was intended to extend the battery life, and I believe that is no longer the issue here. f there would be an advantage to it, I am not aware of it. It might be some thing that could be switched into circuit when batteries are used.

[Paul Joppa]

The PJCCS is intended to reduce distortion and improve isolation from any battery noise; it actually decreases battery life by about 17%.

Without modification, you can use a single supply for both tubes, but you would have to find a way to match the tubes and use matched pairs.

With mods and regulated supplies, you can do quite a number of other interesting things, like using LEDs for bias, shunt regulating the high voltage power, using a full-scale C4S, etc. None of these have been developed at present, they're just ideas.

[4krow]

OOPs, well, it was intended to do something, thats for Shure(pun intended).

[Paul Birkeland]

With mods and regulated supplies, you can do quite a number of other interesting things, like using LEDs for bias, shunt regulating the high voltage power, using a full-scale C4S, etc. None of these have been developed at present, they're just ideas.

I actually built exactly this a few years ago.  Created a 105V gas regulated rail fed by a C4S with two EROS power supply boards making regulated filament voltage (3V instead of 1.5V), and full-scale C4S loads on the 3S4's, two power transformers, etc.

It was an insane amount of work just to create a Quickie that plugged into the wall, but it was a fun developmental experiment.  All the weight that piled up in the chassis seemed to reduce the microphonics too.