Amplifier transistor matching?

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Ken Smith" <kensmith@green.rahul.net> wrote in message
news:d8mp0d$bev$4@blue.rahul.net...
> In article <42ae674a$0$16492$afc38c87@news.optusnet.com.au>,
> Mr.T <MrT@home> wrote:
> >
> >"Ken Smith" <kensmith@green.rahul.net> wrote in message
> >news:d8k3nn$cra$1@blue.rahul.net...
> [....]
> >> I suspect that the cells in the 9V are actually a little better than
the
> >> AA in energy per volume but I don't think it is by enough to make up
for
> >> the about 1/3rd of the space that is not actually a cell.
> >
> >I note you have included NO data to back up your assertion.
> >Your claim of more energy per unit volume is looking dubious then.
>
> The numbers are in another part of this thread, kindly posted by
> someone else and they support my suggestion.

The figures are rather misleading, but you are probably correct this time.
Your "I suspect that the cells in the 9V are actually a little better than
the AA in energy per volume" is still doubtful though.
I still think a DC-DC inverter is the best solution, as you can have small
and/or higher capacity as well as lower battery costs.
However this thread is getting too far into comparing apples with oranges,
IMO.

MrT.

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

In article <42b1187d$0$16705$afc38c87@news.optusnet.com.au>,
Mr.T <MrT@home> wrote:
[....]
>The figures are rather misleading, but you are probably correct this time.

I think the figures are no more misleading than many.

>Your "I suspect that the cells in the 9V are actually a little better than
>the AA in energy per volume" is still doubtful though.

Pry apart a 9V battery and look at how the cell is constructed. There is
very little there that is not the active part of the cell.

--
--
kensmith@rahul.net forging knowledge

 

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"Jonathan Westhues" <google-for-my-name@nospam.com> wrote in message
news:Vj9se.7292$yU.572117@news20.bellglobal.com...
> "Mr.T" <MrT@home> wrote in message
> news:42b114b3$0$16493$afc38c87@news.optusnet.com.au...
> > Yes I read it, and still say a D cell has more energy per unit volume.
> > Possibly per unit weight, but I'll let you do the calculation for that
if
> > you like
>
> I used the alkaline Energizer Industrial series, because Digikey sells
> them. All capacities are to 0.8 V per cell, at 25 mA. That puts 9V
> batteries at a slight disadvantage, because that is more watts with a 9V
> than a 1.5V, but it looks like the error is small enough that I wouldn't
> do better trying to read a capacity off the graph.
>
> The prices are in ones. They provide a volume, which appears to be more
> or less the volume of the cylinder, but I also calculated the `bounding
> box' volume.
>
> AA cell:
> m=23 g, Q=2779 mA*h, E=4168 mW*h, $=0.75 CAD, V=8.1 or 9.8 cm^3
> E/m = 181, E/V = 515 or 425, E/$ = 5557
>
> D cell:
> m=142 g, Q=20500 mA*h, E=30750 mW*h, $=1.69 CAD, V=55.9 or 69.4 cm^3
> E/m = 216, E/V = 550 or 443, E/$ = 18195


Thanks for showing that I was right and a D cell does in fact have more
energy per unit volume, and is FAR better in energy per dollar.
Frankly I couldn't be bothered going to the trouble you have, so I'm
impressed you did even though it proves you were wrong.


> 9V battery:
> m=45.6 g, Q=625 mA*h, E=5625 mW*h, $=2.86 CAD, V=21.1 cm^3
> E/m = 123, E/V = 267, E/$ = 1966
>
> 6V lantern battery:
> m=665 g, Q=18000 mA*H, E=108000 mW*h, $=13.02 CAD, V=440.4 cm^3
> E/m = 162, E/V = 245, E/$ = 8295
>
> The energy figures are wrong because the voltage declines during the
> life of the cell, but they will be equally wrong for all types so I
> think that the numbers can be compared.
>
> So that means that a AA cell is twice as good as (E/V) or 50% better
> than (E/m) a 9V battery. A D cell is about as good as (E/V) or 20%
> better than (E/m) a AA cell. That is sort of like what I expected.

Which puzzles me why you claimed otherwise then?


> What's wrong with the lantern battery though? Is there a good reason why
> it's worse or did I make a silly mistake somewhere? Different capacity vs.
> internal resistance tradeoff?

They have always been a rip off such that adapters were even made to fit 4 D
cells instead. The E/V is pretty similar to the other rip off, the 9V
battery though.

MrT.

 

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Mr.T" <MrT@home> wrote in message
news:42b13882$0$13943$afc38c87@news.optusnet.com.au...
> > AA cell:
> > m=23 g, Q=2779 mA*h, E=4168 mW*h, $=0.75 CAD, V=8.1 or 9.8 cm^3
> > E/m = 181, E/V = 515 or 425, E/$ = 5557
> >
> > D cell:
> > m=142 g, Q=20500 mA*h, E=30750 mW*h, $=1.69 CAD, V=55.9 or 69.4 cm^3
> > E/m = 216, E/V = 550 or 443, E/$ = 18195
>
>
> Thanks for showing that I was right and a D cell does in fact have more
> energy per unit volume, and is FAR better in energy per dollar.
> Frankly I couldn't be bothered going to the trouble you have, so I'm
> impressed you did even though it proves you were wrong.
>
> [...]
>
> > So that means that a AA cell is twice as good as (E/V) or 50% better
> > than (E/m) a 9V battery. A D cell is about as good as (E/V) or 20%
> > better than (E/m) a AA cell. That is sort of like what I expected.
>
> Which puzzles me why you claimed otherwise then?

You may wish to check the From: header. That was my first post to the
thread.

Jonathan

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

Hello Rich,

> Hasn't someone already mentioned the 6X AAA pack? Only a few mm bigger
> than a 9V, but lasts considerably longer? ...

Yes, but that would be a kludge. It isn't rocket science to design stuff
so it can work off a couple AA NiMH. What's the big deal?

Regards, Joerg

http/www.analogconsultants.com

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

Hello Arny,

> Readily available DC-DC converters seem to want at least 2.7
> volts input voltage, to produce 5 volts. So, you're stuck
> with using 2 AA cells, which are somewhat longer and wider
> than one 9 volt cell.

You can build your own DC-DC with cheap logic chips and that works just
fine down to 2V.

Also, nearly any function can be achieved with circuitry that works at
2V without a converter. I am glad that Sennheiser has finally done it as
well. Their G2 mics can take two AA NiMH. Way to go. Thing is, if they
hadn't done it we wouldn't have bought their stuff anymore.

> It's probably the cost that dominates most design decisions
> for consumer products. A DC-DC converter could add $20-30 to
> the final cost.

Nah, the last one I designed was well under a Dollar. Ok, mass
quantities but even with low qties it wouldn't have been a lot more.

> It seems like a single-AA cell solution could be practical
> for higher end wireless mics and earphones for pro audio,
> for example.

Yes. But it requires that engineers learn to design down to transistor
level again. With opamps it usually isn't going to work without the cost
going through the roof.

Regards, Joerg

http/www.analogconsultants.com

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

On Thu, 16 Jun 2005 21:25:03 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

[snip]
> I am glad that Sennheiser has finally done it as
>well. Their G2 mics can take two AA NiMH. Way to go. Thing is, if they
>hadn't done it we wouldn't have bought their stuff anymore.
>
[snip]

Joerg, Which G2 model (lapel mike, with receiver) do you recommend?
Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http/www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

Hello Jim,

> Joerg, Which G2 model (lapel mike, with receiver) do you recommend?
> Thanks!

Don't know yet but I will have to figure that out anyway for our church.
Probably this weekend. When I found out I'll let you know. First I'll
have to find a reasonable dealer (good prices) but that's the easy part.

Regards, Joerg

http/www.analogconsultants.com

 

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Jonathan Westhues" <google-for-my-name@nospam.com> wrote in message
news:Vulse.7613$yU.616660@news20.bellglobal.com...
> You may wish to check the From: header. That was my first post to the
> thread.

My sincere apologies.

MrT.

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news6mse.2844$NU5.601@newssvr13.news.prodigy.com...

> Yes. But it requires that engineers learn to design down to transistor
> level again. With opamps it usually isn't going to work without the cost
> going through the roof.

By the way, while many op-amp circuits published specify a supply coltage of
+- 15 volts, or +- 9 volts, many circuit designs will work with +- 3 volts,
which is easily achieved with two pairs of AA cells.

Also, many circuits will take more power from one side of the power supply
than the other; so if you're using batteries to provide a +- power supply,
it's worth testing them to see if only half need replacing.

Tim

 

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Tim Martin" <tim2718281@ntlworld.com> wrote in message
news:0GCCe.1147$yH4.833@newsfe2-win.ntli.net...
>
> "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
> news6mse.2844$NU5.601@newssvr13.news.prodigy.com...
>
> > Yes. But it requires that engineers learn to design down to
transistor
> > level again. With opamps it usually isn't going to work without the
cost
> > going through the roof.
>
> By the way, while many op-amp circuits published specify a supply
coltage of
> +- 15 volts, or +- 9 volts, many circuit designs will work with +- 3
volts,
> which is easily achieved with two pairs of AA cells.
>
> Also, many circuits will take more power from one side of the power
supply
> than the other; so if you're using batteries to provide a +- power
supply,
> it's worth testing them to see if only half need replacing.
>
> Tim

I just had to bash the hell out of a mini Maglite to get the innermost
AA cell out of it. It had started to leak and the corrosion on the end
was just enough to prevent it from coming out. I had to smakc it
against a concrete floor, with a few layers of paper towel on it to give
just a small amount of give.

Reason for saying this is that it'e really poor advice to give to reuse
half spent batteries. Works really great if the equipment takes a
single cell. But if you put a half spent battery in series with a new
one, it's likely that the half spent one will be discharged to zero and
beyond, leaking in the process. I think if I had two of four cells run
down faster than the other two, I would swap the sets halfway thru their
life. Better yet, get a piece of equipment that's not so poorly
designed that it runs down one set faster than the other.

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:11dnmgl96bnou12@corp.supernews.com...
>
> "Tim Martin" <tim2718281@ntlworld.com> wrote in message
> news:0GCCe.1147$yH4.833@newsfe2-win.ntli.net...
> >
> > "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
> > news6mse.2844$NU5.601@newssvr13.news.prodigy.com...
> >
> > > Yes. But it requires that engineers learn to design down to
> transistor
> > > level again. With opamps it usually isn't going to work without the
> cost
> > > going through the roof.
> >
> > By the way, while many op-amp circuits published specify a supply
> coltage of
> > +- 15 volts, or +- 9 volts, many circuit designs will work with +- 3
> volts,
> > which is easily achieved with two pairs of AA cells.
> >
> > Also, many circuits will take more power from one side of the power
> supply
> > than the other; so if you're using batteries to provide a +- power
> supply,
> > it's worth testing them to see if only half need replacing.
> >
> > Tim
>
> I just had to bash the hell out of a mini Maglite to get the innermost
> AA cell out of it. It had started to leak and the corrosion on the end
> was just enough to prevent it from coming out. I had to smakc it
> against a concrete floor, with a few layers of paper towel on it to give
> just a small amount of give.
>
> Reason for saying this is that it'e really poor advice to give to reuse
> half spent batteries. Works really great if the equipment takes a
> single cell. But if you put a half spent battery in series with a new
> one, it's likely that the half spent one will be discharged to zero and
> beyond, leaking in the process. I think if I had two of four cells run
> down faster than the other two, I would swap the sets halfway thru their
> life. Better yet, get a piece of equipment that's not so poorly
> designed that it runs down one set faster than the other.

Measuring and matching used batteries is not that difficult, if you need to
use them in pairs. Also, some sources for used batteries are applications
where they were originally used in pairs. I collect and cull AA's from RF
mics all the time with little ill-effect. Sometimes I come in from a gig
with my pockets literally bulging with AA's. I usually just match them by
open-circuit voltage and put them in different piles matched within a 0.1 or
..05 volts of one another. Anything below 1.4 volts, I usually either
relegate to the kids' CD/Mp3 players or discard.

It saves me hundred$ a year, at least.

jak
>
>

 

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Watson A.Name - "Watt Sun, the Dark Remover""

> Better yet, get a piece of equipment that's not so poorly
> designed that it runs down one set faster than the other.

OK. Suppose we have a circuit that draws 20 milliamps at -3v, and 220
milliamps at +3 volts. And suppose our power supply is four 1.5v 2200mAh
batteries, wired so one pair provides +3v, and the other pair provides -3v.

Is it possible to redesign the power supply to do better than replace the
+3v pair of batteries every 10 hours, and the -3v pair of batteries every
110 hours? (So for 110 hours of operation, we'd need to replace 12 pairs of
batteries.)

Tim

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

Tim Martin wrote:
> "Watson A.Name - "Watt Sun, the Dark Remover""
>>Better yet, get a piece of equipment that's not so poorly
>>designed that it runs down one set faster than the other.
>
> OK. Suppose we have a circuit that draws 20 milliamps at -3v, and 220
> milliamps at +3 volts. And suppose our power supply is four 1.5v 2200mAh
> batteries, wired so one pair provides +3v, and the other pair provides -3v.
>
> Is it possible to redesign the power supply to do better than replace the
> +3v pair of batteries every 10 hours, and the -3v pair of batteries every
> 110 hours? (So for 110 hours of operation, we'd need to replace 12 pairs of
> batteries.)

Make a switching powersupply using 6V input and outputing
two 3V voltages?

Use a latching relay to switch the batteries (3V <> -3V)
every once and a while?

 

[Guest]

Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Tim Martin" <tim2718281@ntlworld.com> wrote in message
news:3PsEe.5181$YL5.2604@newsfe2-win.ntli.net...
>
> "Watson A.Name - "Watt Sun, the Dark Remover""
>
> > Better yet, get a piece of equipment that's not so poorly
> > designed that it runs down one set faster than the other.
>
> OK. Suppose we have a circuit that draws 20 milliamps at -3v, and 220
> milliamps at +3 volts. And suppose our power supply is four 1.5v
2200mAh
> batteries, wired so one pair provides +3v, and the other pair
provides -3v.
>
> Is it possible to redesign the power supply to do better than replace
the
> +3v pair of batteries every 10 hours, and the -3v pair of batteries
every
> 110 hours? (So for 110 hours of operation, we'd need to replace 12
pairs of
> batteries.)
>
> Tim

I would use a DC-DC converter to get the minus 3V, at 20mA. SHould take
just a 555 and a cap and a couple rectifiers. A V doubler with a zener
seems like it would do the trick.

http/ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm#5volts.g
if
But use a CMOS 555 if the supply is less than 5V. But the CMOS 555 may
not source enough current, I'm not sure how much it can handle.

http/www.mpja.com/productview.asp?product=2308+PS This one is already
assembled.

http/www.build-it-electronics.com/page4.htm It doesn't have to be this
fancy.

http/www.national.com/ms/LB/LB-18.pdf

 

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Archived from groups: sci.electronics.basics,sci.electronics.design,rec.audio.tech,alt.audio.equipment (More info?)

"Kristian Ukkonen" <kristian.ukkonen@iki.fi> wrote in message
news:kkuEe.168$Dl5.67@read3.inet.fi...
>
> Tim Martin wrote:
> > "Watson A.Name - "Watt Sun, the Dark Remover""
> >>Better yet, get a piece of equipment that's not so poorly
> >>designed that it runs down one set faster than the other.
> >
> > OK. Suppose we have a circuit that draws 20 milliamps at -3v, and 220
> > milliamps at +3 volts. And suppose our power supply is four 1.5v
2200mAh
> > batteries, wired so one pair provides +3v, and the other pair
provides -3v.
> >
> > Is it possible to redesign the power supply to do better than replace
the
> > +3v pair of batteries every 10 hours, and the -3v pair of batteries
every
> > 110 hours? (So for 110 hours of operation, we'd need to replace 12
pairs of
> > batteries.)
>
> Make a switching powersupply using 6V input and outputing
> two 3V voltages?
>
> Use a latching relay to switch the batteries (3V <> -3V)
> every once and a while?

Seems like a lot of extra effort and expense for no net benefit.
If you improve the circuit by converting the 6V to +/- 15V instead,
(assuming that does provide some benefit for the circuit involved) at least
there may be some point to it all.
Otherwise it would probably be easier to provide a battery low indicator for
each pair of cells.

MrT.

 

[chiaki014]

Hi Cor-san,

I do not read thru all of the comments here, but below is my short, maybe too late notice for you.

> One is a 2SC960/LA43 the other one is a 2SA607/LA43E.
> Replacement transistors have been reported not to work
> satisfactorily on these Marantz circuits.
> I was finally able to find 2SC960 transistors but not with
> the same LA43 subscript.

L ... L-rank of hFE (High J-K-L-M-N Low)
A ... A-lot. Detail is not disclosed from NEC
43 ... Made in 1974.3

I have no idea about the last E for your 2SA607.
If there is a S in circle or (1) on package of these NEC's Tr, this is the sign of special screening for industrial use.

As you may know, 2SC959 is identical to 2SC960, except latter one is shipped with small heatsink.
Same on 2SA606 and 2SA607.

Though some Japanese OTAKUs are discussing No-name lot or A lot 2SC959/960 sounds much better than the other lots, but basically you should care about hFE and Vbe, as most of guys on this board suggested.

Very important notice for you is that, in Japan, these 2SC959/960 or 2SA606/607 is regarded as the finest sound quality transistors ever made in Japan. I personally have some experiences through my handmade or modds that these transistors produced amazingly open-air, detailed, deep, vivid and passionate sound never heard from other TRs.

These transistors were already discontinued, and in Japan, even second hand used 2SC959 still has re-sale value of 10USD.

Even if your newly bought 2SC and 2SA are not matched, just put them into your amp. I believe, they will sound uncomparablly better than any other matched pair transistors.
If your Marantz is not your most favorite amp, my recommendation is to try your new 2SC960/2SA607 on your most favorite equipment. fT of thses transistors are not so high, so you can try them without very severe concern, for output stage of pre-amp, or driver stage of main-amp.