DENON POA-8000 Power Mono Block -Your opinion!

[rajkumar_]

Hi AK friends! couple of the day I will going to pickup DENON POA-8000 Power amplifier (Mono block) anyone have opinion or advise about this model, see the attachment pictures for reference. Beautiful and very good performance (Tried at the seller shop) actually planed to sale my old gear McIntosh MC240 & C20! Very hard to find (free) manuals online! This amp released on 1981 at the time price 350,000 YEN (one block priece) = 3700 USD follow link for details: http://66.163.168.225/babelfish/transla ... -8000.html
Raj

 

[bolly]

no opinion or advice, but they look very very nice! :thmbsp:

 

[mhardyman]

200W Class A - Highly regarded for their time. Very rare outside Japan. I was lusting after a set then I saw the price tag... sigh.

Denon never made junk. Great find!

 

[guiller]

Beautiful units! Congratulations and enjoy them!

 

[vinyldavid]

Those are just gorgeous :drool:

 

[Vinylcalle]

One of my absolute favorites, even tough I have never seen them in real life.

One advice I have is that I reed something about a turned down bias to keep the amps from overheating. So you might want to controll that they are not getting to hot.

Perhaps mounting some kind of fan for cooling.

Would love to here more about them and to see soom pictures of perhaps the inside close ups of the back etc.

Best Regards Carl

 

[VinylHanger]

Meh. they're OK.

Just playin'. Those are as with many folks one of my dream pieces. I love Denon and those are towards if not at the top. Enjoy. :yes:


Edit: I just noticed where you are from. I am sure there are more than few members who would love to see some pictues from your area in the photo forum. :thmbsp:

 

[rajkumar_]

Denon POA-8000

I gather some information about this amp:
"DENON released (1981 - 1984) extremely rare mono blocks which were scarcely distributed outside Japan and which didn't seem to sell much there either, although awarded Stereo Sound's "Best Product" and "State of the Art" awards...
Feature: Monophonic power amplifier which adopted the DENON non-feedback system.
In POA-8000, it turned around from the system which negates dynamic distortion, and the non-feedback system which does not generate dynamic distortion from the beginning is adopted.
The glass epoxy radical board of 140micro of Copper-foil thickness which made circuit resistance the minimum, and the oxygen-free-copper board are used for the circuit board of a power transistor part. This is suppressing the signal transmission loss by the circuit manual training at the time of high output.
The digital display carried in the front of a front usually carries the speaker referential function of SP1orSP2 at the time of operation with the muting counter function. Furthermore, the self-diagnostics function is carried, and it confirms whether the set is operating stably.
This amp pure Class "A" circuit so runs hot, but many people said never failure, Denon design for that! I would like to run this amp wormer; I will install some cooling fans. (Note: I will pick up this amp on coming Saturday). See some pictures below taken from web sites.
Thanks! Raj

 

[megasat16]

You'll find it is very picky about what preamplifier it is used with. Yeah, I got a pair of these but one is broken. I am fixing the broken one now but I have difficulty obtaining the required parts and it's taking a lot of time trying to gather parts.

 

[rajkumar_]

Megasat16, do you have any documents for this amp? I don't have Denon preamp. I have Nakamich CA7A, Kenwood L-07c and Yamaha C2a! By the way what's theproblem your amp?
Regards,

 

[megasat16]

I also don't have the matching Denon preamp for it. I've tried a lot of very nice solid state preamp (more than 10) with it. I think the matching preamp is very important for this Denon amp.

Are your units 220-240V asia versions? Mine are 120V U.S versions.

As for the documentations, I only have schematic on paper so far. The problem with mine is quite a few and some JFET transistors are really not easily available.

 

[rajkumar_]

Mine Japanese version 100V, is it possible have schematic scan copy? I also searching DENON preamp the best matching is PRA-6000 (very hard to find) / my friends said PRA 1000 or 1500 matching? Thanks!

 

[Vinylcalle]

I have no idea were you will find dokuments for it, try to contact Denon perhaps. As far as preamp if you can´t find a pra-6000 other denons from the same area is pra1000 and pra 2000 but style wise maybe the 1500 is a better match.

As far as I am aware the PMA790/950/970 and POA1500/3000/8000 have all basically the same type of circuit some of them claimed to be class A. But they are not really pure class A operation. Theres as allways in an AB construction a certain amount of witch is class A for some not that much but for these denons realatively much and most of all probably poa3000/8000. After this there is a circuit who automatically raises the current so its allways higher then what the output power is. So there is like an adaptive class A kind of thing.

This is how I have learnt about it.

I have an PMA-790 by the way. Its a really great amplifier. So well built it makes a Accuphase look almost like something out of the supermarket (ok not really but just as good).

Best regards Carl

 

[djv8ga]

I can't think of any amp(s) I would rather have.

 

[megasat16]

I have no idea were you will find dokuments for it, try to contact Denon perhaps. As far as preamp if you can´t find a pra-6000 other denons from the same area is pra1000 and pra 2000 but style wise maybe the 1500 is a better match.

As far as I am aware the PMA790/950/970 and POA1500/3000/8000 have all basically the same type of circuit some of them claimed to be class A. But they are not really pure class A operation. Theres as allways in an AB construction a certain amount of witch is class A for some not that much but for these denons realatively much and most of all probably poa3000/8000. After this there is a circuit who automatically raises the current so its allways higher then what the output power is. So there is like an adaptive class A kind of thing.

This is how I have learnt about it.

I have an PMA-790 by the way. Its a really great amplifier. So well built it makes a Accuphase look almost like something out of the supermarket (ok not really but just as good).

Best regards Carl

Even though the POA-3000, POA-3000Z, and POA-8000 came from the same era, they all have different designs electronically. Likewise, POA-3000RG and POA-S1 are totally different beast from the earlier Denon.

The matching preamp for POA-8000 is entirely different from that of POA-3000 and POA-3000RG. I have POA-3000 as well as POA-3000RG. They don't give me any problem when using with many different preamps.

And no, the POA-3000 and POA-8000 is the only ones that use Class A logo on the front of the amp. The rest don't have Class A logo coz they are not Class A. Both the POA-3000 and POA-8000 both use Push Pull Class A design. But it's the only similarities between POA-3000 and POA-8000. The circuits are totally different from input to the output. Push-Pull Class A design is not PURE Class A but it's a sub-class of Class A.

 

[rajkumar_]

Hello, how about Accuphase preamp I'm looking C-275 can it match? very hard to find Denon PRA-6000? Accuphase C200 is available don't have idea can match??:scratch2:
Raj

 

[Vinylcalle]

Even though the POA-3000, POA-3000Z, and POA-8000 came from the same era, they all have different designs electronically. Likewise, POA-3000RG and POA-S1 are totally different beast from the earlier Denon.

The matching preamp for POA-8000 is entirely different from that of POA-3000 and POA-3000RG. I have POA-3000 as well as POA-3000RG. They don't give me any problem when using with many different preamps.

And no, the POA-3000 and POA-8000 is the only ones that use Class A logo on the front of the amp. The rest don't have Class A logo coz they are not Class A. Both the POA-3000 and POA-8000 both use Push Pull Class A design. But it's the only similarities between POA-3000 and POA-8000. The circuits are totally different from input to the output. Push-Pull Class A design is not PURE Class A but it's a sub-class of Class A.

Well I never said anything about the 3000z and 3000rg.

By the way the PMA950/970 also got the class A logo. I´ve allways thought they removed them on later models since it wasn´t a real class A design.

Regarding the preamp I was just telling him about other denon preamps. Since there are just a handfull of pra6000 out there I guess its pretty hard to find one.

MvH Carl

 

[megasat16]

Well I never said anything about the 3000z and 3000rg.

By the way the PMA950/970 also got the class A logo. I´ve allways thought they removed them on later models since it wasn´t a real class A design.

Regarding the preamp I was just telling him about other denon preamps. Since there are just a handfull of pra6000 out there I guess its pretty hard to find one.

MvH Carl

No! You didn't say anything about POA-3000Z and POA-3000RG. I mentioned them to make you aware that they are all different and these two amps and others don't give me a problem with matching preamps.

I am not a fan of Integrated units so I didn't know about the PMA-950/PMA-970 but seems like Denon did made these two integrated models you mentioned with Push-Pull Class A output stage.

Later Denons seems to utilize Class AB output stage with Optical Class A Biasing scheme. I think what it means is that the Pre-driver stage before output transistors are biased in Class A. But the biasing mechanism used opto-couplers for purer and cleaner transfer of signal to them (which I fail to understand). I also have POA-2400A with Optical Class A so I need to look at it sometimes.


The matching PRA-6000 preamp is very rarely seen and it must be for a reason. May be people who owns them keep them or most of them broke down and unrepairable.

 

[megasat16]

Hello, how about Accuphase preamp I'm looking C-275 can it match? very hard to find Denon PRA-6000? Accuphase C200 is available don't have idea can match??:scratch2:
Raj

I have no idea with Accuphase preamp but I also thought about getting an Accuphase preamp. I have older Luxman C-02 I've tried it without much success. Good Luck with the Accuphase pre and let me know if it works well for you.

 

[rajkumar_]

Denon POA-8000 Fixed overheat problem

Hi,
:thmbsp: See the below pictures actual of Denon POA-8000, One amp runs hotter than other amp, local electronic shop guy tried to adjust but there was no any improvement, final I adjusted follow SM. The voltage adjustment not easy, pity hard used two DMM at a time adjust. Finally successfully adjusted and problem solved. The amps run now lower temperature than Kenwood L-07M :guitar: