Battery Sale!

[charger]

D battery shall change under which volt value?

Around 1 volt the d cells stop working.

thanks

[Paul Joppa]

I do not recommend using the 3-volt filament option because the plate voltage is so low, the portion of filament is practically cut off. This will increase the output impedance and the distortion.

You can however parallel multiple cells for longer life. Sometimes AAs are cheaper than Ds per amp-hour, so a pack of paralleled AAs could be more economical.

Long ago there was a large single carbon-zinc cell called No.6. They were about 2.5" diameter and 6.75" long. I don't think anyone ever made an alkaline in that format. They may still exist, but carbon-zinc cells have a short shelf life and less than half the capacity of alkaline even when fresh, so it's not that great a deal.


There also used to be an F cell (IIRC) which was a longer D cell, 1.5 times as long. It went into 6-v lantern batteries, and was made in alkaline chemistry. But it seems to have disappeared, the lantern batteries these days are 1/3 air and 2/3 D cells. 12v lantern batteries also still exist, but in carbon-zinc only.

Wikipedia http://en.wikipedia.org/wiki/List_of_battery_sizes says the PP-9 size is used in marine applications and is still available, it's a 9-v battery with 5000mA-h capacity(!) - but again, only in carbon-zinc as far as I can tell.

[Paul Birkeland]

I do not recommend using the 3-volt filament option because the plate voltage is so low, the portion of filament is practically cut off.

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If you connected the negative leads of each battery to each other, then connected that to pin 5, then connected each red lead to 1/7, couldn't one get away with this without running into cutoff? (Switching power setup like this would be kind of a PITA)

[aragorn723]

I do not recommend using the 3-volt filament option because the plate voltage is so low, the portion of filament is practically cut off. This will increase the output impedance and the distortion.

You can however parallel multiple cells for longer life. Sometimes AAs are cheaper than Ds per amp-hour, so a pack of paralleled AAs could be more economical.

Right, that should say parallel.

[Paul Joppa]

I do not recommend using the 3-volt filament option because the plate voltage is so low, the portion of filament is practically cut off.

-
If you connected the negative leads of each battery to each other, then connected that to pin 5, then connected each red lead to 1/7, couldn't one get away with this without running into cutoff? (Switching power setup like this would be kind of a PITA)

Hah! Didn't think of that - one cell for each half filament. Should work fine.

[charger]

is'nt that aside the great sound the Q produces , one , soon or later becomes tired to feed it with batteries and go searching another good sounding cheap tube preamp ?

[Paul Birkeland]

is'nt that aside the great sound the Q produces , one , soon or later becomes tired to feed it with batteries and go searching another good sounding cheap tube preamp ?

I think the next least expensive directly heated tube preamp might be the BeePre...

[Mike B]

I figure the AA's ought to last a year, the D's 3 months.  I just bought 2 years worth of AA and 1 year of D for twenty bucks.  That should be about 30 bucks for 2 years.  About a buck and a quarter a month.

Change the D's with the change of season and the AA's every new year.  Cost 4 cents a day.

I base this on my listening habit of about 2 hours a day, nine to eleven PM, every night before I go off to sleep.

I don't see a problem.

[aragorn723]

is'nt that aside the great sound the Q produces , one , soon or later becomes tired to feed it with batteries and go searching another good sounding cheap tube preamp ?

I think the next least expensive directly heated tube preamp might be the BeePre...

Out of curiosity, how does the BeePre differ in sound from the Quickie?

[galyons]

... soon or later becomes tired to feed it with batteries and go searching another good sounding cheap tube preamp ?

Feeding with batteries is not an issue, but actually a design plus.  I moved from 4 9v batteries to 3 12v SLA batteries.   I keep the 12v batteries at full charge, when not playing), with an inexpensive float charger. The only hassle is just charging 1 battery at a time.  I will  likely change the D cells to rechargeable's in the near future.

Another good sounding cheap tube preamp is an oxymoron. To get "cheap", it is usually the critical power supply where cost and quality are cut.

Cheers,
Geary

[corndog71]

... soon or later becomes tired to feed it with batteries and go searching another good sounding cheap tube preamp ?

Feeding with batteries is not an issue, but actually a design plus.  I moved from 4 9v batteries to 3 12v SLA batteries.   I keep the 12v batteries at full charge, when not playing), with an inexpensive float charger. The only hassle is just charging 1 battery at a time.  I will  likely change the D cells to rechargeable's in the near future.

Another good sounding cheap tube preamp is an oxymoron. To get "cheap", it is usually the critical power supply where cost and quality are cut.

Cheers,
Geary

Same here.  I only have to charge my 12V batteries once a year.  I've been wanting rechargeable D cells for a while but the good ones (11,000mAH!) are $30 a pair!  It's hard to cough up that much coin but I'll probably do it sometime soon.  A decent D cell charger is kinda pricey too.  Although I just saw at Costco a pack of 14 D cells for $20.

[Paul Joppa]

If you don't mind changing batteries more often (10 hours instead of 100 hours) then you can use AA for the filaments. Might be cheaper when using rechargeables.

I'd worry a little about possible RF interference, but it might be fun to experiment with a solar charger permanently wired to the filament cell. I think solar AA chargers are readily available.

[Chris]

Solar would be an excellent idea... Bottlehead goes GREEN!!!.....

[charger]

that's a good idea!!!

[Doc B.]

I'd worry a little about possible RF interference

and solar flares...