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Smoker
23-12-2011, 03:15
please could someone advise me on this amp? I have been offered one but its faulty right now but when working is meant to be a good amp. if it was fixed , would this a worthwhile purchase for £250?

I was told that 4 speakers were hooked up to it when it blew but the amp wasnt set to the correct ohm setting so now it crackles on one channel.

any advice is appreciated and Merry Christmas too!

StanleyB
23-12-2011, 07:04
You can get a working one for £269 HERE (http://www.ebay.co.uk/itm/Excellent-Denon-POA-2400-Amplifier-200wpc-One-Denons-Best-/270876210099?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item3f117af3b3). I would laugh in the face of whoever offered you that amp at £250 faulty. The output stage transistors are breaking down, and getting them changed is likely to set you back more than £100 in labour and parts. I suggest that you get the working one from eBay ;).

Smoker
23-12-2011, 15:23
lol i hear you big time! that would be crazy, the main issue is that ive never heard it working and the £250 figure would be the price once it has been repaired. the real sticking point is that i havent said yes i'll take it go ahead and repair it and they need to pay to get it fixed but its only worth it if its going to be sold. i do trust the persons judgement on the amp but i just need to be sure its worth it as id still need a preamp as well. would i benefit more by just getting something like a roksan kandy or would that poa-2400 + denon pre-amp beat it price/quality wise?

StanleyB
23-12-2011, 19:44
Don't be fooled by its draconian external looks. Underneath the top cover lies a sleeping dragon that has so far evaded the radar of high eBay prices. A real sleeper from Denon. But make sure you lift some weight and do a bit of a work out before trying to lift it up. Well built power amps don't do diets. At around 35lbs it will need more than a bookshelf to keep it securely in place. And bookshelf speakers are also out of the question. This brute needs floorstanders that can handle the power and dynamic range without ending up with fried voice coils.

What pre-amp ;)? Unless you need a preamp for TT purposes, consider trying out a DAC with a variable output. Those are now far more common these days, and preserve a lot more of the fine musical detail that the majority of preamps would otherwise fail to disclose.

Smoker
23-12-2011, 22:02
thanks for that advice, its owned by my friends father and has been looked after lovingly except for the speaker incident! so by looks you'd think it was new. currently im trying to put together a music system from scratch, so far i have a michell gyrodec thats connected to a michell iso phono stage. right now that connects to a yamaha dsp-595a av amp with bose acoustimass speaker system.

instead id like the michell iso to go into a suitable pre-amp that would work with the poa-2400 then theres the need to purchase speakers that compliment that lot lol

I do agree completely on the workout routine and the right speakers to make a good match. funnily enough i will need help carrying it no doubt! if I went with this beast of an amp what pre-amp would you recommend? the best I could get info wise was to try and match it with the pre-amp that was available when it was sold. as for speakers I would love some suggestions too, im happy to buy second hand classic speakers that have been cared for well. so I could give them a good home :)

StanleyB
24-12-2011, 09:35
I am out of touch with good but easy to obtain preamps. The last seriously decent one I had was from the Pioneer 91 series, but even that had to go after I started using a DAC, and ended up playing my TT via an ADC through the DAC.

Smoker
07-02-2012, 03:03
I have an update on the denon power amp, unfortunately it still hasn't been fixed :( so i have been offered it a very good price (£150) but that is in its current state.

would anyone know of somewhere in the london area that i could take it to for repair? it powers on fine, just one channel crackles as you increase volume.

thanks

looks like ive made some headway ;) it might be in german but i found the service manual and located the output transistors. ive been trying to troubleshoot without the amp with me. ill have it here soon so will update on progrress if anyones interested. sure this must be kids stuff to most here lol if i can get this working the next step is to get some pioneer darlek speakers working lol (no bose!)

bogle111
09-02-2012, 01:02
Nice amp, and as Stanley B says, their prices are bargains at present. Had one courtesy of the Denon rep once and teamed it up with an A Resarch SP8 (or 9), can't remember. Also had a Krell to compare and Bang per buck, made me wonder if the K wasn't a bit dear. £250 is a steel.

Hope you can get it fixed. Though not a technician, wouldn't it be better to change all output transistors at the same time?

Regards

Smoker
09-02-2012, 01:46
hi peter, yes the idea is to get all of them changed at once. luckily my brother is more skilled with electronics as thats his field i shall bow to his superior knowledge with this fix. i found out all the info i could with the service manual, he wouldnt even touch it without a schematic so i know its in safe hands.

so true about what you say about what we get for our money, as i was up for a new stereo amp but nothing for the price could challenge this denon amp when working. esp as it had been replaced with a newer amp by them and was not in use just waiting to be revived. knowing it only had one owner whom i know personally made this worth the trouble.

thanks for the info about a good preamp as thats my next purchase apart from speakers. i have a midi sized technics su-x102 new class a amp which has the preout pins at the back so i can use it temporarily with the denon.
i would like to take in all the advice i can about the preamp as its not my area of strength knowing which matches up best without any knowledge listening wise.

could i ask yours and anyones honest thoughts on the speakers that i may use with the denon, i described them dalek wise but would like to know how they are sound wise. again once these have been given some attention too they will be up for sale. i do like what ive read so far but obviously its not the same as hearing.

Pioneer HPM-150
http://hifi.slovanet.sk/bb/files/thumbs/t_pioneer_hpm150_814.jpg

thanks

Wilbur
09-02-2012, 02:40
Buy amp,buy speakers,fix amp,enjoy:eyebrows:

StanleyB
09-02-2012, 07:43
Hi Raz, if it is crackling on one channel when you turn the volume up, the fault is probably not the output transistors. My suggestion is that it could be a soldering dry joint. So something needs resoldering. As the amp gets a bit hotter on the higher power level, the solder at the faulty connection point is making intermittent contact.
If you ignore my suggestion and just went ahead with changing the output transistors, do keep in mind that:
The quiescent current and offset voltage of the amp needs careful recalibration. Under no circumstances should you ignore those two highly critical calibration!!

Smoker
09-02-2012, 18:53
Hi Raz, if it is crackling on one channel when you turn the volume up, the fault is probably not the output transistors. My suggestion is that it could be a soldering dry joint. So something needs resoldering. As the amp gets a bit hotter on the higher power level, the solder at the faulty connection point is making intermittent contact.
If you ignore my suggestion and just went ahead with changing the output transistors, do keep in mind that:
The quiescent current and offset voltage of the amp needs careful recalibration. Under no circumstances should you ignore those two highly critical calibration!!

Hi , thanks for that info too. i was told checking for dry joint would be the first thing to check because the age of the amp its been sat for a few years out of use. I'll be learning and shown what to check, so i'll get a chance to test the output transistors before anything gets changed. with anything I find it much more enjoyable and rewarding making good of whats broken. :)

Smoker
21-02-2012, 03:04
Quick update and a request :) if anyone knows of a Denon PRA-1200 or Denon PRA-1500 Pre-Amp for sale, please could you let me know. Thank you.

Tested the power amp's fuses and output transistors which were all fine, the fault lies with the right channel, if raised the small speaker A indicator will flash and any continued use at a high level results in the amp shutting down. Pressing the protection button fixes this, low level playback the amp functions fine. I made a list of the caps and will be changing them when they arrive, they are the weakest link for an amp this age so im guessing more detective work is needed.

One other question I have is whether the input level controls on this amp are normal (10 is lowest volume and 0 is the highest) or do I own the spinal tap edition :eyebrows:

http://desmond.imageshack.us/Himg138/scaled.php?server=138&filename=img20120221025602.jpg&res=medium

Here she is powered up :)
http://desmond.imageshack.us/Himg829/scaled.php?server=829&filename=img20120221022514.jpg&res=medium

Smoker
05-04-2012, 17:54
She lives and found a friend too :)

http://i44.tinypic.com/anddzs.png

ursus262
05-04-2012, 19:00
hi peter, yes the idea is to get all of them changed at once. luckily my brother is more skilled with electronics as thats his field i shall bow to his superior knowledge with this fix. i found out all the info i could with the service manual, he wouldnt even touch it without a schematic so i know its in safe hands.

so true about what you say about what we get for our money, as i was up for a new stereo amp but nothing for the price could challenge this denon amp when working. esp as it had been replaced with a newer amp by them and was not in use just waiting to be revived. knowing it only had one owner whom i know personally made this worth the trouble.

thanks for the info about a good preamp as thats my next purchase apart from speakers. i have a midi sized technics su-x102 new class a amp which has the preout pins at the back so i can use it temporarily with the denon.
i would like to take in all the advice i can about the preamp as its not my area of strength knowing which matches up best without any knowledge listening wise.

could i ask yours and anyones honest thoughts on the speakers that i may use with the denon, i described them dalek wise but would like to know how they are sound wise. again once these have been given some attention too they will be up for sale. i do like what ive read so far but obviously its not the same as hearing.

Pioneer HPM-150
http://hifi.slovanet.sk/bb/files/thumbs/t_pioneer_hpm150_814.jpg

thanks

Ooh I want!

Smoker
06-04-2012, 01:10
what would be a reasonable price for the hpm-150's ?

thanks

ursus262
06-04-2012, 12:19
Why is that? Do you have a pair for sale?

Smoker
06-04-2012, 17:47
Why is that? Do you have a pair for sale?

I have a chance to buy a pair but I havent been given a price yet. they've been re-foamed very recently, apart from that they are in excellent condition.

I'm trying to find out what they usually sell for with the hope i can afford them!

thanks

Smoker
11-04-2012, 00:57
after a week of listening to the system (gyrodec-iso - denon pre & power - ms40s) all i know is im happy with what im hearing.

the first to be played was...:)

http://991.com/NewGallery/Coleman-Hawkins-The-Gilded-Hawk-527841.jpg

sweet, thats me done!

Smoker
21-04-2012, 17:35
or is it? lol those hpm-150's are tempting me...

bogle111
21-04-2012, 20:28
or is it? lol those hpm-150's are tempting me...

Hi Raz,

In the states, many of the HPM series are well thought of. The 100's are a bit criticised now, but 150s are rarer. AK is a better source for current prices. As someone else said, just replace the $ for £ and you are about right.

It must be remembered that the Japanese used to test "their" (have to do this as this site wants to put in "there") speakers with recordings from Japan, where there instruments are brighter, thus you will find the treble is "clear" unlike many UK speakers of that era and a brighter balance as well.

Just have a duff NS1000 tweeter, - last year could have bought a pair of complete speakers for £400 from the valleys, now the minimum price seems to be £900 and £155 for a single tweeter. Vintage audio just seems to be going up & up... so is older Pioneer in the states. At a good price they will be a bargain.

I have a complete vintage Japanese system in one room, and though this may sound like heresy, it is the one that gets used the most.

I still lust after a good AR SP9II or III though after having one, quite magical to my ears. I have always reckoned that it was the pres that tailored the sound, the amp shouldn't, at least any where near as much.

Regs
Pete

Smoker
23-04-2012, 10:46
Thank you Pete, thats a great help. I have a chance to get a pair but waiting on a price for delivery. My aim is to have just one set of speakers for the long term.

myles
15-04-2013, 21:10
I know, I know, holy thread revival! I now have one of these Denon POA2400 amps and first thing I want to deal with is the speaker binding posts. They only take a bare wire and I'd like to use bananas, or at least have the option.
Easy?
Any other little nuggets about this amp will be appreciated also!

Glen B
18-04-2013, 20:02
I know, I know, holy thread revival! I now have one of these Denon POA2400 amps and first thing I want to deal with is the speaker binding posts. They only take a bare wire and I'd like to use bananas, or at least have the option.
Easy?

Its easy enough to do if you have decent skills. I've done many binding post upgrades. Most were "drop-in" requiring no modifications. A small number required either modification of the mounting plate holding the original posts, or making up a new mounting plate. You may get some inspiration in the following thread. See some of my upgrades at posts #36, 47, 48, 49 and 55 in the thread. http://www.audiokarma.org/forums/showthread.php?t=292166

myles
18-04-2013, 20:04
Thanks Glen, I have it in situ now and it sounds excellent, doesn't get ruffled by a bit of drive.

As for the binding posts, I will enjoy it for a few more weeks then whip its clothes off and have a look.

Thanks again,

Myles