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Tobiah Tobiah is offline
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Default Denon poa 2200

I have a chance to buy one for $100. Sounds like
a good deal, but there is chatter here from time
to time about old capacitors, and this is probably
a 20+ year old amp. Should I be concerned about its
age? They guy says it's a class A also. Is that
always a good thing?

Thanks
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William Sommerwerck William Sommerwerck is offline
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"Tobiah" wrote in message
...

I have a chance to buy one for $100. Sounds like a good deal,
but there is chatter here from time to time about old capacitors,
and this is probably a 20+ year old amp. Should I be concerned
about its age? They guy says it's a class A also. Is that always
a good thing?


For $100? Grab it. Unless the amp itself, or this particular sample, has
"problems" (such as spontaneously blowing its output transistors for no good
reason), you're getting a deal -- though you should ask the seller why he
wants so little for it.

If the power supply caps need replacing, it isn't difficult or horribly
expensive. Twenty years isn't horribly old for high-quality electrolytic
caps.

Class A operation, in theory, is always a good thing. But the amp's overall
design is ultimately more important.


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Tobiah Tobiah is offline
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Default Denon poa 2200

For $100? Grab it. Unless the amp itself, or this particular sample, has
"problems" (such as spontaneously blowing its output transistors for no good
reason), you're getting a deal -- though you should ask the seller why he
wants so little for it.


He had up for $200 originally, but had no takers. I
made the offer, and I'm thinking he's going to take
it. The asking price is now $150. I may offer $125.
I hope he's not on this list

Thanks,

Tobiah
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PStamler PStamler is offline
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You gor yourself a deal. Even if it needs new capacitors, you can
replace them for not a lot of money, and you're ahead of the game.

Solid-state Class-A amplifiers usually decent sound, so that makes
them a good thing. If you're into saving money on your electric bills
(and A/C bills in the summer), they're not such a good thing.

Peace,
Paul (sitting 3 feet from an 8-Watt Class-A amp as I type)
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William Sommerwerck William Sommerwerck is offline
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Some points of clarification...

Most class A amps aren't, really. A 100W/ch class A amplifier would require
a huge power supply and ginormous heat sinks because, as someone else
pointed out, it's effectively running "full power" at all times.

Most class A amps (as someone else pointed out) are class A only up to a
certain point, which seems to run about 10% of full output.

Some AB amps are "high bias" (as yet another person pointed out), and
provide class A operation up to five or ten watts, which is fine for
moderate listening levels.

If the manufacturer will tell you what the bias current is, you can compute
the peak class A output by doubling the bias value, squaring it, and
multiplying by the load resistance.




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On 11/21/2011 4:31 AM, William Sommerwerck wrote:
Some points of clarification...

Most class A amps aren't, really.


I saw some evidence online that this one is not, really.
It is a bit of a monster though. It weighs 40 pounds.
I like it because of the good reputation, and that the
front is mostly blank. The input gains are on the back.
The front only has power and A/B speaker switches and a
few lights. It will look really cool sitting under my
1402VLZ Pro.

I ended up having to offer $150, which
was accepted. Now to close the deal, which doesn't always
happen after an email conversation.

Tobiah
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William Sommerwerck William Sommerwerck is offline
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"Tobiah" wrote in message
...
On 11/21/2011 4:31 AM, William Sommerwerck wrote:


Some points of clarification...
Most class A amps aren't, really.


I saw some evidence online that this one is not, really.
It is a bit of a monster though. It weighs 40 pounds.
I like it because of the good reputation, and that the
front is mostly blank. The input gains are on the back.
The front only has power and A/B speaker switches and a
few lights. It will look really cool sitting under my
1402VLZ Pro.


But your 1402VLZ Pro might not remain "cool" (ar-ar).


I ended up having to offer $150, which was accepted.
Now to close the deal, which doesn't always happen
after an e-mail conversation.


I assume you know to be cautious. On eBay, I've had a few sellers who
shipped damaged or malfunctioning merchandise (only one made good on it), or
took my money and didn't ship anything. Then there was this guy and his
girlfriend who were just plain psycho. They decided to back out of the deal
without bothering to tell me. I didn't lose any money, but...


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Tobiah[_4_] Tobiah[_4_] is offline
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On 11/22/2011 05:46 AM, William Sommerwerck wrote:
wrote in message
...
On 11/21/2011 4:31 AM, William Sommerwerck wrote:


Some points of clarification...
Most class A amps aren't, really.


I saw some evidence online that this one is not, really.
It is a bit of a monster though. It weighs 40 pounds.
I like it because of the good reputation, and that the
front is mostly blank. The input gains are on the back.
The front only has power and A/B speaker switches and a
few lights. It will look really cool sitting under my
1402VLZ Pro.


But your 1402VLZ Pro might not remain "cool" (ar-ar).


I heard that this amp runs pretty cool, but I'll be careful.


I assume you know to be cautious. On eBay, I've had a few sellers who
shipped damaged or malfunctioning merchandise (only one made good on it), or
took my money and didn't ship anything. Then there was this guy and his
girlfriend who were just plain psycho. They decided to back out of the deal
without bothering to tell me. I didn't lose any money, but...


I've had excellent luck with eBay, but this was a local thing.
I'm going to pick up the amp in person this afternoon, and will
at least be able to verify that it is working.

If it was suffering from old capacitors, how could I check for that?
Just see whether it sounds good to my ear at that particular moment?

Thanks,

Tobiah
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William Sommerwerck William Sommerwerck is offline
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"Tobiah" wrote in message
...

If it was suffering from old capacitors, how could I check for that?
Just see whether it sounds good to my ear at that particular moment?


If the caps were actually "bad", the amp might not come on, or it might trip
its protective circuits, or have other obvious problems..

My gut feeling is that a 20-year-old amplifier is unlikely to have bad caps.
Get the owner to demo the amp before you buy it.


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Arny Krueger[_4_] Arny Krueger[_4_] is offline
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Default Denon poa 2200


"Tobiah" wrote in message
...
I have a chance to buy one for $100. Sounds like
a good deal, but there is chatter here from time
to time about old capacitors, and this is probably
a 20+ year old amp. Should I be concerned about its
age? They guy says it's a class A also. Is that
always a good thing?


Looking around, it appears to be a 220 wpc home audio-type power amp from
the early 1990s.

I see just one on eBay, bid up to about $150, with a reserve of some where
around twice that, which seems salty.

No way is it full class A, but it might be class A up to say, 30 wpc.
Doesn't matter, anyway.

Here's the service manual:

http://vintageshifi.com/denonpoa2200.pdf

In my book $100 is just about mad money. If it works, you have a deal and if
it does not, then you aren't out that much money.

20 year old capacitors could be in good shape, but a thorough bench test
would give you the "final answer".




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I see just one on eBay, bid up to about $150, with a reserve of some where
around twice that, which seems salty.


I saw one under completed auctions that went for ~$250 + $45 shipping.
So yeah, I'll go have a listen, and likely buy it for the now $150.
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On 11/22/2011 2:30 PM, William Sommerwerck wrote:
"Arny wrote in message
...

In my book $100 is just about mad money. If it works, you have
a deal, and if it does not, then you aren't out that much money.


Seconded.



I turned out to be $150, but I picked it up, and hooked it up.
It's hard to A/B amps, but I believe that I'm hearing individual
instruments with better separation, and the bass seems as they say,
"controlled", albeit plentiful. I actually think I'm now better able
to pinpoint some of the things that I don't like as being in the
source material. I was using a JVC receiver earlier.

Or maybe I'm just optimistic, but my old receiver died, and I needed to
scratch and itch. I was worried that the old capacitors, should they
have changed over the years, would gradually modify the sound from
the amps new state. I'm not sure what the actual concern about the
caps is, whether its quality, or simply working or not.

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?

Thanks,

Tobiah
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PStamler PStamler is offline
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On Nov 22, 6:52*pm, Tobiah wrote:
On 11/22/2011 2:30 PM, William Sommerwerck wrote:

"Arny *wrote in message
...


In my book $100 is just about mad money. If it works, you have
a deal, and if it does not, then you aren't out that much money.


Seconded.


I turned out to be $150, but I picked it up, and hooked it up.
It's hard to A/B amps, but I believe that I'm hearing individual
instruments with better separation, and the bass seems as they say,
"controlled", albeit plentiful. *I actually think I'm now better able
to pinpoint some of the things that I don't like as being in the
source material. *I was using a JVC receiver earlier.

Or maybe I'm just optimistic, but my old receiver died, and I needed to
scratch and itch. *I was worried that the old capacitors, should they
have changed over the years, would gradually modify the sound from
the amps new state. *I'm not sure what the actual concern about the
caps is, whether its quality, or simply working or not.

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. *Does that sound sane?


No; consider that most output amplifiers have higher distortion when
the output level is higher. That goes double for Mackie gear, which
often has decent mic preamps but low-grade opamps in later stages,
including the outputs.

I'd set the Mackie's output faders at their nominal level (probably
about 14dB down from maximum -- there'll d a mark) and use the
channel faders (or, if you're listening to an external source, the
control for that source) to set the level so that the highest peaks
very occasionally light up the bottom yellow LED in the Mackie's level
meters. Don't let the other yellow lights light up, and don't let any
of the red lights light up ever.

Once you've done that, use the level control(s) on your new amplifier
to set the volume to what you want to hear.

Turning the power amp controls way down and driving the Mackie's
outputs hard is a sure recipe for high distortion.

Peace,
Paul
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William Sommerwerck William Sommerwerck is offline
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I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?


I don't know about sanity, but that's usually the way it's done.

I can't speak to the other poster's claim that the Mackie has too much
distortion at higher outputs. Try it both ways and draw your own
conclusions.


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Scott Dorsey Scott Dorsey is offline
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Tobiah wrote:

I turned out to be $150, but I picked it up, and hooked it up.
It's hard to A/B amps, but I believe that I'm hearing individual
instruments with better separation, and the bass seems as they say,
"controlled", albeit plentiful. I actually think I'm now better able
to pinpoint some of the things that I don't like as being in the
source material. I was using a JVC receiver earlier.


Really, you might want to listen to some of the earlier advice about the
GFA 535 or GFA 555, or some of the specific Hafler models mentioned. Not
thjat the Denon might not turn out to be good, but then again it might not.

Or maybe I'm just optimistic, but my old receiver died, and I needed to
scratch and itch. I was worried that the old capacitors, should they
have changed over the years, would gradually modify the sound from
the amps new state. I'm not sure what the actual concern about the
caps is, whether its quality, or simply working or not.


Measure frequency response. Measure noise. If they are good, the thing is
not suffering cap failures. Well-designed and well-constructed equipment does
not have a problem with electrolytics aging. Poorly-designed equipment does,
either because the caps used are poor or because they are in places in the
signal path where the values are critical or because the whole system runs too
hot and bakes the electrolytics out. There is a lot of poorly-designed gear
out there, some of it very expensive.

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?


There is a good introduction to gain staging in the Yamaha Sound Reinforcement
Handbook. I highly recommend it.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."


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PStamler wrote:

On Nov 22, 6:52 pm, Tobiah wrote:
On 11/22/2011 2:30 PM, William Sommerwerck wrote:

"Arny wrote in message
...


In my book $100 is just about mad money. If it works, you have
a deal, and if it does not, then you aren't out that much money.


Seconded.


I turned out to be $150, but I picked it up, and hooked it up.
It's hard to A/B amps, but I believe that I'm hearing individual
instruments with better separation, and the bass seems as they say,
"controlled", albeit plentiful. I actually think I'm now better able
to pinpoint some of the things that I don't like as being in the
source material. I was using a JVC receiver earlier.

Or maybe I'm just optimistic, but my old receiver died, and I needed to
scratch and itch. I was worried that the old capacitors, should they
have changed over the years, would gradually modify the sound from
the amps new state. I'm not sure what the actual concern about the
caps is, whether its quality, or simply working or not.

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?


No; consider that most output amplifiers have higher distortion when
the output level is higher. That goes double for Mackie gear, which
often has decent mic preamps but low-grade opamps in later stages,
including the outputs.

I'd set the Mackie's output faders at their nominal level (probably
about 14dB down from maximum -- there'll d a mark) and use the
channel faders (or, if you're listening to an external source, the
control for that source) to set the level so that the highest peaks
very occasionally light up the bottom yellow LED in the Mackie's level
meters. Don't let the other yellow lights light up, and don't let any
of the red lights light up ever.

Once you've done that, use the level control(s) on your new amplifier
to set the volume to what you want to hear.

Turning the power amp controls way down and driving the Mackie's
outputs hard is a sure recipe for high distortion.

Peace,
Paul


Good advice. What I've found with Mackie's older boards (pre-Onyx line)
is that by observing the metering at every step in gain staging,
starting with the pre/line input(s) and keeping it into the green
LED's, never getting into the yellow ("caution!") lights, gets a
surprisingly clean signal with no intrusion of noise floor.

--
shut up and play your guitar * http://hankalrich.com/
http://www.youtube.com/walkinaymusic
http://www.sonicbids.com/HankandShaidri
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William Sommerwerck wrote:

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?


I don't know about sanity, but that's usually the way it's done.

I can't speak to the other poster's claim that the Mackie has too much
distortion at higher outputs. Try it both ways and draw your own
conclusions.


I can verify that restraining output level on Mackie boards makes a
world of difference, a better world.

--
shut up and play your guitar * http://hankalrich.com/
http://www.youtube.com/walkinaymusic
http://www.sonicbids.com/HankandShaidri
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Tobiah Tobiah is offline
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Default Denon poa 2200

I assume that I should turn the input gain controls down as far as
I can, while achieving my desired loudest volume with the Mackie
at unity. Does that sound sane?


No; consider that most output amplifiers have higher distortion when
the output level is higher. That goes double for Mackie gear, which
often has decent mic preamps but low-grade opamps in later stages,
including the outputs.

I'd set the Mackie's output faders at their nominal level (probably
about 14dB down from maximum -- there'll d a mark) and use the
channel faders (or, if you're listening to an external source, the
control for that source) to set the level so that the highest peaks
very occasionally light up the bottom yellow LED in the Mackie's level
meters. Don't let the other yellow lights light up, and don't let any
of the red lights light up ever.

Once you've done that, use the level control(s) on your new amplifier
to set the volume to what you want to hear.

Turning the power amp controls way down and driving the Mackie's
outputs hard is a sure recipe for high distortion.


What I did, was to put the Mackie at unity throughout, and adjust the
amp's inputs so that I was hearing what I thought was the loudest volume
that I'd ever want to hear, then a tad more. I'm listening to some
music right now (O' Brother where art though soundtrack) at a nice loud
level, and the CTL Room fader is sitting at about -11 dB.

Part of my motivation for this method was that the amp is sitting under
my desk, and the input gains are in the back. I wanted to set them
so that I'd never feel the need to crawl back down there and fiddle with
them again. I think they ended up at about 40%. Maybe I'll bump them
up to 50%, considering what you said about the mixer.





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Arkansan Raider Arkansan Raider is offline
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Scott Dorsey wrote:
Tobiah wrote:
I turned out to be $150, but I picked it up, and hooked it up.
It's hard to A/B amps, but I believe that I'm hearing individual
instruments with better separation, and the bass seems as they say,
"controlled", albeit plentiful. I actually think I'm now better able
to pinpoint some of the things that I don't like as being in the
source material. I was using a JVC receiver earlier.


Really, you might want to listen to some of the earlier advice about the
GFA 535 or GFA 555, or some of the specific Hafler models mentioned. Not
thjat the Denon might not turn out to be good, but then again it might not.


Hiya', Scott! What thread were the Haflers mentioned in? I didn't see it
in this thread. I'm pretty sure that the TA series weren't included--as
mine stunk up the joint. They're better than nothing, but they keep
dying on me. TA1100 and TA1600.

I'm thinking that the P series and the DH series have good reputations,
but I've not gotten a good listen.

I'm still trying to save up the cash to repair my McIntosh MC2100, as I
managed to blow one side out due to a bad driver on a Polk Audio Monitor
3 speaker.

---Jeff
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Scott Dorsey Scott Dorsey is offline
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Arkansan Raider wrote:

Hiya', Scott! What thread were the Haflers mentioned in? I didn't see it
in this thread. I'm pretty sure that the TA series weren't included--as
mine stunk up the joint. They're better than nothing, but they keep
dying on me. TA1100 and TA1600.


What's failing on them? They are pretty easy to work on. They're kind of
cut down compared with the Trans-Nova amps and that includes the power supply,
but they are decent for the price. However, they don't have a lot of
protection in there.

I'm thinking that the P series and the DH series have good reputations,
but I've not gotten a good listen.


The DH series has a seriously undersized power supply, but that's life on
the cheap end of the market. The P series is pretty similar to the TA series
inside as I recall, but fan colled, etc.

I'm still trying to save up the cash to repair my McIntosh MC2100, as I
managed to blow one side out due to a bad driver on a Polk Audio Monitor
3 speaker.


I never liked those things myself, but they are rugged as hell and easy to
work on.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."


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Tobiah Tobiah is offline
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On 11/19/2011 1:39 PM, Tobiah wrote:
I have a chance to buy one for $100. Sounds like
a good deal, but there is chatter here from time
to time about old capacitors, and this is probably
a 20+ year old amp. Should I be concerned about its
age? They guy says it's a class A also. Is that
always a good thing?

Thanks


What's up with the two sets of inputs on the back?
One is supposed to be for hooking up a CD player
directly to the amp, while the other is meant to
take preamp output. They both seem to sound the
same at the same level, and they are both affected
by the level knobs. Is this just a marketing gimmick
from when CD's were the rage?

Thanks,

Tobiah
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William Sommerwerck William Sommerwerck is offline
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"Arkansan Raider" wrote in message
...
Scott Dorsey wrote:


Really, you might want to listen to some of the earlier advice about
the GFA 535 or GFA 555, or some of the specific Hafler models
mentioned. Not that the Denon might not turn out to be good, but
then again it might not.


I used to own the XL280, and it drove Acoustats very well.

A friend of mine bought an Adcom (the 555, I think) for his M-L 'stats. It
sounded terrific.

An amplifier can be cheap and good.


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"Tobiah" wrote in message
...

What's up with the two sets of inputs on the back?
One is supposed to be for hooking up a CD player
directly to the amp, while the other is meant to
take preamp output. They both seem to sound the
same at the same level, and they are both affected
by the level knobs. Is this just a marketing gimmick
from when CD's were the rage?


Since there are separate input levels controls and they are on the back
panel, probably no intent that the amp be used without a preamp or a CD
player or other device with its own level control.

The two inputs are hooked together prior to the channel gain control. The CD
input differs in that there is a 7.5 k resistor in series, as a jumper over
to the Normal input. The input impedance of the power amp circuit itself is
no more than 47 K and the input level control is 50 K.

I see a lot of potential for the second input to be a frustrating feature to
actually use. Its really not suitable for use with most CD players or other
devices that lack volume controls.

For more information, please check the service manual at
http://vintageshifi.com/denonpoa2200.pdf . This probably just about
everything that is known at this time.


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