Adcom 5802 VS dual 565's

BIZILL

i'm looking to power my sda-srs 1.2TL's and these two amps have got my attention. a few here on the board have the 565's available to sell. but i see the 5802 is pretty much like having two 565's placed in one chassis. and two of these are available right now. one is on ebay and one is on audiogon. (5802's that is)

anyway, size is not much of an issue. i rather feel two beasts of amps are more ballsy than one. so dual monoblocks don't scare me. i may possibly even go another route altogether, but before i make any final decisions, i want to know all your takes on one vs the other. hopefully i can get some input from those of you who have actually owned or auditioned BOTH amps.

thank you all in advance...:)

heiney9

These really aren't similar in design at all. Like we discussed in PM if the mono's have been updated your safe there. (2) Mono's have the coolness factor a single stereo amp can't match.

I like both, but I'd choose the 5802 because it will give all the 565's will and it's more refined and slightly more "musical" especially on vocals and acoustic and jazz. But that's just my .02c

Either would be excellent driving your SDA's. Both need the negative terminals tied together to make them common ground.

Good luck on making a decision. It's a tough one.

H9

BIZILL

i hear ya heinz. i also wanted to hear a few more opinions as well. another factor that will come into play will be price. i believe the 5802 comes in a little more expensive than the 565's. but pretty much about the same. and i was under the impression that perhaps mono's would be 'better' because they'd each have their own transformers and what nots. i haven't seen the innards of a 5802 so i can't judge build quality. though i'm sure is just as good if not better.

was the 5802 adcom's 'flagship' amp or did most consider the mono's to be?

and just to throw into the mix...how would a rotel RB1080 stack against these two adcoms? sure, more power, but how's 'bout quality? i was also contemplating gebby's offering.

PolkClyde

Do you guys think that a Adcom amp mono block would sound better than say a carver mono block with the same wattage/ current.Let me ask it another way.... will a $5000 amp sound better than say a $2000 krell amp. I said krell but you can put any amp in there. Name your favorite amp in the place of the krell.

Thanks guys

PC

heiney9

The 5802 came much later than the 565's. It's a Mosfet design heavily influenced by Nelson Pass. $2195 retail 2 years ago as Adcom's flagship. 300wpc.

Review:

http://www.avrev.com/home-theater-power-amplifiers/stereo-amplifiers/adcom-gfa-5802-stereo-power-amplifier.html

Stereophile gave it a perennial class B rating. If that means anything.

Audiogon has a 5802 for $795 right now

565's came out in 89

5802 came out in 98

H9

P.s. I'd choose both over the Rotel; especially the 5802

BIZILL

that's the one on audiogon. as well there is one on the 'bay. i guess the thing that's really buggin' me is that i haven't ever purchased anything this expensive without SEEING it first as would be the case with the audiogon and the 'bay. both sellers only have as good of pictures as they have listed. the offering here on club polk would come from a trusted member with high quality pics. but if the 5802 is the 'better' amp, then i'm not sure which route to go...

heinz, thanks for your opinions and keep 'em coming, if you will. thanks a bunch!

BIZILL

heiney, what say you to this? the reviews seem to favor more the 565's vs the 5802...

565's

5802

and don't take this as me not appreciating your opinion h9. just trying to make an informed and the best decision as i will take this purchase to the grave with me. (don't hold me to my word - upgraditis) i had my mind SET on the 565's until recent. so i'm back to square one.

ben62670

565 BJT's.
5800-5802 Mosfet.
It's a preference. I had a 5800 that was a great amp. I kept the 565's for cool factor, and better heat dissipation at the silly low ohms that I sometimes run(less than 2 at times).

BIZILL

that was a positive point for the mono's for sure, keeping cool. i doubt i'll ever run these beasts very hard. but another positive for the monos is if i changed plans (say it ain't so) then down the line i would have two serious units to use for subwoofer amps.

but if the 5802 is more 'musical'....i **** you not, i'm at a stalemate right about now, having to choose between the two...i appreciate all comments fellas and fellettes.

heiney9

BIZILL wrote: »

heiney, what say you to this? the reviews seem to favor more the 565's vs the 5802...

565's

5802

and don't take this as me not appreciating your opinion h9. just trying to make an informed and the best decision as i will take this purchase to the grave with me. (don't hold me to my word - upgraditis) i had my mind SET on the 565's until recent. so i'm back to square one.

I don't put much emphasis on audioreview posts, simply because I have nothing to base the review on. I don't know these people, their systems, likes, dislikes etc. On a board like this the opinion can be taken a little more seriously just because we can have an open dialog like we are now. Certainly looking at all avenues is a good thing.

I like them both; as you will too. Of all the newer Adcom's I'd pick the 5802 because of all the press it has gotten in the past and because of Nelson Pass's involvement and because it's newer. The 565's are a **** to find someone who actually can work on them. I know Ben can and that's a positive but without his "hands on" knowledge you'd be up a creek, IMO.

H9

heiney9

BIZILL wrote: »

that was a positive point for the mono's for sure, keeping cool. i doubt i'll ever run these beasts very hard. but another positive for the monos is if i changed plans (say it ain't so) then down the line i would have two serious units to use for subwoofer amps.

but if the 5802 is more 'musical'....i **** you not, i'm at a stalemate right about now, having to choose between the two...i appreciate all comments fellas and fellettes.

The reason the 5802 runs so hot is 1) heavily biased into class A operation (a good thing) and 2) because Mosfets have/need a higher bias voltage. Nothing at all to get concerned about.

H9

BIZILL

alrighty there sir heiney. i just made you proud, i hope. i just got the 5802 that was on audiogon. the one on ebay keeps rising and is already $100 past what the seller from audiogon and i agreed upon. dude, it's totally gonna suck waiting for **** shipping!

ben62670

Can you get someone to video tape you smiling when you hook that sucka up!

BIZILL

well, i'm keeping my fingers crossed the amp will be in as good of shape as the sda 1.2tl's are. i hope this was the best route going with the 5802 over the 565. i'm sure both are wonderful amps. and hopefully i won't need you ben, to ever have to service or fix this amp. no offense. but you know what i mean. shipping and all that equals buku money.

this was my very first audiogon transaction. i popped my audiogon cherry!

Roy Munson

I think you'll be very happy with the 5802..mosfet Adcoms are imho much smoother than their grainier predecessors.

Enjoy!

BIZILL

it's gonna be a very long week. anyone know if the 5802 has the 'thump' upon power-up? i just want to know what to expect beforehand.

I-SIG

While I haven't heard either of the Adcoms, I'd have to say that as long as the specs are adequate for the wattage, get the more musical piece of gear.

The 2 Parasounds I had, based on specs, should blow the Cary amp away. When you listen, the Cary does so much more with less kVA, watts, etc. it's not even funny.

Wes

george daniel

BIZILL wrote: »

it's gonna be a very long week. anyone know if the 5802 has the 'thump' upon power-up? i just want to know what to expect beforehand.

My 565's don't "thump" too much,,anyway, not like the 555's did.

heiney9

BIZILL wrote: »

it's gonna be a very long week. anyone know if the 5802 has the 'thump' upon power-up? i just want to know what to expect beforehand.

Congrats.............you will be extremely happy . You bought it right too! Anything under $900 is a good deal. Can't remember if it thumps, but it should be mild............even if it does always turn the amp off first and let the caps drain.

Start looking around for a good pair of spades and some very thick wire to make your jumper for the negative speaker posts so you're ready to go when the amp arrives.

Generally Audiogon is a good place to do business. Here's hoping it arrives safe and as described.

If I didn't want to try something other than Adcom (I've had it; heard it for years) I would have jumped all over this. It's on my short list but there are some other's ahead of it; simply because they are different not because the 5802 is a lesser amp.

H9

hoosier21

heiney9 wrote: »

Start looking around for a good pair of spades and some very thick wire to make your jumper for the negative speaker posts so you're ready to go when the amp arrives.H9

For what? I don't think he will need to tie the neg terminal together on the 5802.

heiney9

hoosier21 wrote: »

For what? I don't think he will need to tie the neg terminal together on the 5802.

Yep, he sure will. Non-common ground amp as are all the 5xxx series. Darqueknight and others have done it in the past. No issue's there with tying them together.

These Adcom's have primary and secondary windings and they don't share the same ground. Not a big deal at all.

H9

hoosier21

heiney9 wrote: »

Yep, he sure will. Non-common ground amp as are all the 5xxx series. Darqueknight and others have done it in the past. No issue's there with tying them together.

These Adcom's have primary and secondary windings and they don't share the same ground. Not a big deal at all.

H9

I am sure your right, but the 5802 has a single transformer with 2 secondary taps, how is it possible they are not common ground?

I will do some looking around and get my learn on.

heiney9

Here's a thread I opened on DIY Audio awhile ago. All talking about similar Adcom non-common ground issues

http://www.diyaudio.com/forums/showthread.php?s=&threadid=65855&highlight=

Systems

hoosier21 wrote: »

I am sure your right, but the 5802 has a single transformer with 2 secondary taps, how is it possible they are not common ground?

It must be dual mono after the transformer.It would still be common ground (non bridged outputstage) otherwise strapping the negative terminals together would be problematic.

hoosier21

well the short answer is tie the grounds at the amp and he is all good,

my ignorance will go on

ben62670

Pulled from H9's link

Hi Arif,
No, in this amp, the channel grounds are referenced independently to chassis ground through a 100 ohm resistor each. If the amp is run into the Polk's without shorting the two ground terminals, Brock's friend may burn out the two 100 ohm resistors.

There is but one transformer with independent windings supplying power to each channel. Each amp is treated as if it's a mono block. If you look at the schematic, it shows the main ground for each channel connected to chassis ground through this 100 ohm resistor. Neat idea eh (Canadian)?

I didn't even have to look for the input ground. The inputs are referenced to the channel ground first.

-Chris

I know this is fact.
Ben

Systems

http://www.polkaudio.com/forums/showthread.php?p=921006&highlight=forte#post921006
That Adcom is configured exactly like this Forte H9 was inquiring about.As I mention in post #18 you can see the resistors conected to each supply then to chassis ground.

BIZILL

shitski. welp, i got the amp for $750 shipped/paypalled. so i'm crossing my fingers that there are no issues with the amp. i spoke with the gentlman briefly over the phone and he's dealt with many an audio gear in his time. he's got a large amount of 100% positive feedback as well. probably 50/50 on sales vs purchases. anyway, the one on ebay is already $100 more and has two days left to bid on it. of course, the ebay fella is the original owner. the audiogon i got from is the second owner, but supposedly he purchased it from his buddy. we all know it'd be nice to have SOME history on the amp.

wes, when i get it set up, it's time for you to come give a listen and educate me if need be.

BIZILL

live and learn. i hate when sellers don't have high rez pictures to send via email. the only known issue he told me about was that at some point they did open the cover to check the innards and at some point he lost a screw. supposedly adcom sent him a replacement, but the wrong screw? so they rigged her up with some self-tapping screws to keep her uniform. (uhg/ick) i didn't find this out until after he accepted my offer. anyway, no big whoop. i'll get some nicer bolts from my work and be all good again. what i'm hoping though is that these self-tapping screws didn't need to take too big a bite outta the metal and opening the whole diameter too much. as well, i hope no metal shavings dropped down onto anything only to be left.

i'll inspect it (visually, as that's all my scope of experience will allow) when it gets here. dude used it for his mains for awhile and then gave it subwoofer duty to drive some snell's. he doesn't use the snells any longer and had this pup sitting around and decided it's too nice to not sell it and let someone else stroke themselves whilst listening to it.

so like i said, it'll be a very long week waiting and i'm sure this was a worth-while purchase. especially since i got it for a good price. i'm sure it's in pristine operational order. i think the screws are ugly as SIN! but i wasn't sure what i was even looking at until he informed me. again, i'll replace them with something more appropriate and take it from there.

heiney9

BIZILL wrote: »

live and learn. i hate when sellers don't have high rez pictures to send via email. the only known issue he told me about was that at some point they did open the cover to check the innards and at some point he lost a screw. supposedly adcom sent him a replacement, but the wrong screw? so they rigged her up with some self-tapping screws to keep her uniform. (uhg/ick) i didn't find this out until after he accepted my offer. anyway, no big whoop. i'll get some nicer bolts from my work and be all good again. what i'm hoping though is that these self-tapping screws didn't need to take too big a bite outta the metal and opening the whole diameter too much. as well, i hope no metal shavings dropped down onto anything only to be left.

i'll inspect it (visually, as that's all my scope of experience will allow) when it gets here. dude used it for his mains for awhile and then gave it subwoofer duty to drive some snell's. he doesn't use the snells any longer and had this pup sitting around and decided it's too nice to not sell it and let someone else stroke themselves whilst listening to it.

so like i said, it'll be a very long week waiting and i'm sure this was a worth-while purchase. especially since i got it for a good price. i'm sure it's in pristine operational order. i think the screws are ugly as SIN! but i wasn't sure what i was even looking at until he informed me. again, i'll replace them with something more appropriate and take it from there.

That's a killer deal. Just killer for this amp (bad screw or not). You will like very much. Get to work on making a ground "strap" :D.

H9

BIZILL

not just strap, i need to make some quality speaker wire as well as get on some quality interconnects. that'll be just the beginning....