Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: Jim R. on July 27, 2012, 03:51:03 PM
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Scheming -- always scheming on how to do things a little different and so they work nicely in the spaces I have. One thing I'm considering right now is an external power pack, so I'm wondering how many total connections from the batteries to the circuit there are. My guess is that there are 3 from the D cells -- a common center and two other poles, and 2 from the 36v supply, for a total of 5. Is this right or do the D cells require two connections each? This is the difference between a fairly cheap and easily available umbilical connector set (5-pin mini-xlr) or a more 6-pin option. Though I suppose an octal socket and plug will also work, but I'd like to keep it a bit more compact and locakable if possible.
Thanks,
Jim
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the heaters 'D' cells have 4, the 36V have two. I 'beefed up' the 36V wireing but left the heater wires as cheap skinny stuff.
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Thanks, Eric,
Guess I'll have to ponder this a bit more.
Thanks,
Jim
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Did you get the PJCCS upgrade? If not, then I'd recommend it. Have read that it can give up to 100 hours of battery life for regular alkalines. Can't verify yet since I'm still on my first set. It sounds better than the Adcom GFP-555ii preamp. Will probably be putting it up for sale soon...
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Yes, I ordered the pjccs right from the start -- though some folks have reported somewhat better than 100 hours with it and standard alkaline batteries.
As for the connections, I realized that they are directly heated so they should have separate supplies.
Thanks,
Jim
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Hey Jim,
I replaced my nine volts for the first time yesterday, approx. 106 hours. I kept a close watch on that, still on the first pair of D-cells. Bought some nine volts in bulk at Costco the other day. If I can get that kind of battery life regularly then I'll be a happy camper. There is not much else in my house that has that kind of battery life. I am lucky if I get 10 hours on the HiFiman.
Cheers,
Shawn
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Shawn,
That's still a lot of bedtime listening, which is where I will most likely end up using the quickie.
Thanks,
Jim
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Hey Philippe - That Adcom was a great inexpensive preamp as I remember. I never had one, but I remember it. How was the Quickie better? Is the Quickie stock?
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For what it's worth, Duracell and others list 18 amp-hours for an alkaline D cell, which is 180 hours at 100mA. 9-v are rated 595mA-hours, so about 200 hours at 1.5mA per channel (average draw over the life of the battery).
Real-world tests seem to give a bit more than half the rating, I found 2 mentions of 12A-h for D cells and one of 300-500mAh for 9-v batteries. None of the tests are done at the low currents used in Quickie, and end-of-test voltages are all over the place. I figure the battery is dead when it drops to 2/3 of the nominal (1v for D cells, 6v for 9-v).
NiCd and NiMH hold a pretty constant 1.2v per cell until they die quite suddenly; that's a good voltage for quickie use.
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When my quickie is complete, I will be using LI-ION 9V batts, and copper top alkaline for the heaters. I have the PJJS upgrade, so it will be interesting to see the outcome.
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Paul,
Thanks for anticipating my next question about current draw :-).
--Jim
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So, wonder if a dual 36v supply approach would work? I found some NiMH 9v (actually 8.4) cells and a charger that can handle up to 10 of these at a time) but the max capacity rating is 250 mAH -- so I figure if I go with two sets of 4 -- one for each channel, that should give about the same life as standard alkalines, no?
Any concerns regarding doing this as far as the PJCCS is concerned? Maybe I'd need a second PJCCS as well?
Don't worry, I've already decided to build this in the 8 x 10 format chassis as the output caps I plan to use are rather huge.
-- Jim
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The only issue is you need another pole on the power switch for a dual-mono battery. (Paralleling batteries is problematical, in case you were thinking of it...) The PJCCS has two independent channels.
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Its funny about the voltage on the 3s4's. I have noticed that my Quickie still works with main voltage as low as 16V. Whether the tubes continue to amplify or not seems to be more dependent on the heater voltages. When those dip too low it stops.
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Paul,
No paralelling here -- that's why I wanted to go with the dual mono supply idea, and as long as the channels on the pjccs are independent, it should be just fine this way. So, this is what I'm a gonna do -- which is really good as I've already ordered the parts to do it. :-) Not exactly cheap, but probably a lot cheaper in the long run and I wont be tossing batteries away all the time.
-- Jim
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'if only there were some kind of device that you could plug into the wall outlet, that umm transformed the voltage somehow to 36v....maybe someday'
Ok, enough of that. But here is a question/thought, when I worked at the phone company, batteries were used as a filter, i.e., they stopped any noise that was put in their path. The same idea is used in PS Audio power regenerators(which is one reason I think that they are so great). So, you know where I'm heading here. Is it too costly to implement an idea using batteries in a DC supply that is originally fed from an AC source?
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Greg,
Of course you can do this, but I'm trying to get away from AC cords, transformers, bridges, etc. What you describe will certainly work (I use such a setup for my mac mini DC supply -- smart charger, large AGM battery, and a regulator/filter that goes to the mini, the external hard drive and my turntable's motor) but it probably won't be as quiet as straight batteries, and of course batteries aren't silent or perfect either (that's why the final regulator/filter in my computer supply).
I've never tried NiMH for audio power, so I guess I'll find out what it's like.
As for me, the space I want to use this in is very starved for AC outlets, so a battery preamp is a good thing here. I've got 2 fast, smart NiMH chargers -- one that does two D cells at a time and the other that does up to 10 9v rectangular cells at a time, so for me it is just a matter of once every couple of months or whatever it turns out to be, taking all the batteries out at once, popping them all into their respective chargers, then putting them back in the preamp -- and I can keep the chargers elsewhere in the room.
With the quickie, it's so simple, so elegant, fairly flexible on power supplies, uses low voltage and doesn't get hot, so it opens a whole load of possibilities for creative expression that you simply can't do with the other kits. Once I verify that this dual mono setup and the battery sizing will work well for me, then I'll probably build some more of these as headphone amps -- especially for my neices and nephews when they get to an appropriate age. Got one coming up in January that will be 12, and assuming my sister is ok with it, she's going to get one nice birthday/christmas present from her aunt and uncle. Again, the low voltage and lack of heat play a big part in being able to do this. I just can't at this point see my sister allowing something like the s.e.x. or Crack in the neices' bedroom. And of course it will finally give me an excuse to make something in purple :-).
-- Jim
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Heck, you can add a DPDT toggle switch for the dual mono B+ and turn the "high voltage" on and off separately.
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So, how about a 4pdt and do it all at once?
-- Jim