Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: Len on October 30, 2009, 10:36:07 AM
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I'm thrilled with using the Quickie as an active low pass filter (or a front end for a passive low pass).
As a rule, I turn on my system about an hour before I start listening, which makes a big difference. Since the system sounds so good now, I stayed home for a long listening session today. I warmed up everything but the Quickie because I didn't want to use up battery power unnecessarily. But I noticed that the bass sounded better after about 20 minutes.
Do the same warmup rules apply to battery powered systems? I had thought warmup was due to AC charging of caps, but now suspect that tube warmup has something to do with it. BTW, the Quickie tubes do not seem to get warm on the outside.
Any thoughts?
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Len,
I had not been warming mine up, nor have I noticed any changes to the sound after listening. However, my ears are not that well trained. I am hoping for some listening time tomorrow or Sunday. I will try and pay more attention to the base detail and report back.
Alan
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I've not heard a difference - almost instantaneous "warm-up" and bass response. It might be that your ears are "warming up," though - remember, the device is only half of the equation. Perception is not a fixed property.
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Len, how about you build a DC supply, well 2, that you disconnect when you are ready to listen. You get the warm up without burning battery hours and the magic of pure DC when listening.
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Len, how about you build a DC supply, well 2, that you disconnect when you are ready to listen. You get the warm up without burning battery hours and the magic of pure DC when listening.
Great idea!
The Quickie has a DPDT switch for the filament power. It should be easy enough to wire it so it switches between a charger and the tube - so the battery (cell actually) is charging when it's not running. Get a couple NiCd or NIMH D-cells and you're in business. The charging current can be very small - even if you listen 4 or 5 hours a day, 25mA per cell will replenish the charge. You can use the common ground, the cathode resistor just helps comreol the charging current. Add a resistor for each cell and use any old DC supply/wallwart you have laying around.
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So maybe a DPDT with center off so you can either warm up, listen or have it completely off. No, wait, if you need a charge position then it would be one where it runs completely off the charger voltages (warm up), one where it runs from the batteries and one for charge/off. DPTT would be necessary.
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I have a fairly "new in service" Quickie set up as headphone amp with plate chokes.
For the first 1/2 hour or so of the latest session I thought I was hearing some spitting with "S" and "Z" sounds. After circa 30 mins or so things have calmed nicely.
I have no more than a couple hours total on the unit and perhaps this is "break-in" more than "warm-up".
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Len, how about you build a DC supply, well 2, that you disconnect when you are ready to listen. You get the warm up without burning battery hours and the magic of pure DC when listening.
Great idea!
The Quickie has a DPDT switch for the filament power. It should be easy enough to wire it so it switches between a charger and the tube - so the battery (cell actually) is charging when it's not running. Get a couple NiCd or NIMH D-cells and you're in business. The charging current can be very small - even if you listen 4 or 5 hours a day, 25mA per cell will replenish the charge. You can use the common ground, the cathode resistor just helps comreol the charging current. Add a resistor for each cell and use any old DC supply/wallwart you have laying around.
Here's a schematic (I think what I am actually using; I hope it's not an early version) of the charger I'm using for my 26 output stage. I cut off the 117VAC to the primaries of the charging transformers when the pre is running, so as to avoid any interference. I guess I would figure out a similar scheme for the Quickie.
I noticed when building the Quickie that the HT is indeed switched. That would help in running some idle voltage through the filaments for a "standby mode". IIRC, it should be about 2/3 of the full 1.5V.