Adcom 5800 + Request ?

[walukanis]

I have an Adcom 5800 amp (250w at 8ohm, 400w at 4ohm) and Requests. When going loud (I mean really loud) there is a lot of distortion. I am leaning towards the amps ability to drive ReQuests, especially as they dip into sub 2ohm level....

What amp should I look at, Pass, Krell ? Or maybe my amp is fine and its me going crazy....

I did use search and I couldnt find much about this combination...


Greg

 

[robertawillisjr]

How loud? If you have a sound meter, try and measure the db level.

Keep in mind that all speakers and amplifiers will produce distorted sound if pushed too hard.

I don't mean to preach but loud noises will evenuatlly affect your hearing.

 

[Gordon Gray]

If you are listening at sustained 95db+ levels and continue to do so, be prepared for permanent hearing damage.

 

[Bernard]

If you are listening at sustained 95db+ levels and continue to do so, be prepared for permanent hearing damage.

Also be prepared for tinnitus. It can drive you insane.

 

[walukanis]

Please dont misunderstand me. Its not for sustained periods of time, but it just seems as ReQuests are too hard on the Adcom and I am trying to figure out if that is true or just me.
I thought about going with a pair of GFA-565's but then maybe I should go all out and get some nice Krell...

 

[jmschnur]

I found Outlaw amps not up to my standards for my Vantages. They had a problem with 1 ohm loads at higher audio levels for high frequencies. I went to Bryston amps. Bryston is very nice indeed. Perhaps ADcom has the same issue with 1 ohm impedence loads

I use my 5 channel Outlaw for the Cinema i and 4 NHT surrounds in my system. For that purpose the amp is very fine indeed.

Joel

 

[Sambob2]

Please dont misunderstand me. Its not for sustained periods of time, but it just seems as ReQuests are too hard on the Adcom and I am trying to figure out if that is true or just me.
I thought about going with a pair of GFA-565's but then maybe I should go all out and get some nice Krell...

Greg,
I believe the answer is yes. The impedance of the panels are getting too low at some point and driving the amp to a point where it can't supply the current necesssary. Of course if you are way up on the volume control, you could also be overdriving the amplifier too.

Whatever amplifier you choose to go with, make sure the specifications list the amps ability to deliver power down to below 4 ohms, preferably 2 ohms. Not all amps can double down for each halving of the impedance, but if they can deliver to two ohms you should be good. Here's an explanation of doubling down: (Double down means that the amplifiers output in wattage will double each time the impedance is divided in half. If you have 100 Watts at 8 ohms, a well designed amp will put out 200 watts at 4 ohms. Likewise, a well designed amp should then put out 400 watts at 2 ohms). Of course along with this capability, the amps cost will go up due to larger and better designed internal parts in addition to larger capacitors and weighing a lot more. It sounds (no pun intended) like the Adcom does not have the ability to double down nor the storage capacitance to handle high volume low impedance loads.

 

[churchill]

Get one of the Pass X series of amps and be done with it!

 

[walukanis]

Greg,
I believe the answer is yes. The impedance of the panels are getting too low at some point and driving the amp to a point where it can't supply the current necesssary. Of course if you are way up on the volume control, you could also be overdriving the amplifier too.

Whatever amplifier you choose to go with, make sure the specifications list the amps ability to deliver power down to below 4 ohms, preferably 2 ohms. Not all amps can double down for each halving of the impedance, but if they can deliver to two ohms you should be good. Here's an explanation of doubling down: (Double down means that the amplifiers output in wattage will double each time the impedance is divided in half. If you have 100 Watts at 8 ohms, a well designed amp will put out 200 watts at 4 ohms. Likewise, a well designed amp should then put out 400 watts at 2 ohms). Of course along with this capability, the amps cost will go up due to larger and better designed internal parts in addition to larger capacitors and weighing a lot more. It sounds (no pun intended) like the Adcom does not have the ability to double down nor the storage capacitance to handle high volume low impedance loads.

That is what I was suspecting. The only Adcom I found that had specification provided of being able to go to 2 ohms was GFA-565 monoblock. The amps that have the characteristics you described are mostly a very good amps I noticed (Krell, Pass, etc...). Now all I need is $3k and Im set


Thanks for the answer


Greg

 

[Gordon Gray]

Greg,

You can certainly pick up a used Pass Labs X series stereo amp for under $3K on audiogon.

And based on my experience and others on this forum, you won't be disappointed.

GG

 

[Tosh]

You could go on diyaudio.com forums and ask the designer of the 5800 himself: Nelson Pass. I suspect the amp in normal condition can drive those speakers fine. They're only rated to handle 250W, and the amp can put out 400W into 4 Ohms.
It could be other things making distortion (or noise), like the woofers running out of travel, the panels rattling, or things in the house rattling. How old are the panels?

 

[wallacefl]

I used to have an old Adcom GFA-555 for whole house background music and tried it once with my CLSz2...it would work fine despite its tilted up nature and though the impedence is low at the top of the band not much musical energy is present ie: the amp is not being called on to produce much current.....sounds like it may be driven too hard?

 

[Jungle Jack]

Hello,
While I have not listened to an 5800 in some time, you might want to make sure that the Panels on your Request are in good shape before immediately switching Amplifiers.

Especially if you have used this combo for a sustained amount of time and have not wanted for power, it could possibly be the Panels. With the Request being introduced in 1996, it could be time. If not the original owner, you might want to check out the S/N Decoder to see when your Requests were Manufactured as the Production went from 1996 to 2001.
Cheers,
JJ

 

[Audioseduction]

Get one of the Pass X series of amps and be done with it!

I 2nd that! :music:

 

[Len44]

Whatever amplifier you choose to go with, make sure the specifications list the amps ability to deliver power down to below 4 ohms, preferably 2 ohms. Not all amps can double down for each halving of the impedance, but if they can deliver to two ohms you should be good. Here's an explanation of doubling down: (Double down means that the amplifiers output in wattage will double each time the impedance is divided in half. If you have 100 Watts at 8 ohms, a well designed amp will put out 200 watts at 4 ohms. Likewise, a well designed amp should then put out 400 watts at 2 ohms). Of course along with this capability, the amps cost will go up due to larger and better designed internal parts in addition to larger capacitors and weighing a lot more. It sounds (no pun intended) like the Adcom does not have the ability to double down nor the storage capacitance to handle high volume low impedance loads.

So, for a high quality system, one ought to eliminate from consideration any amplifier that does not advertise in their specifications a doubling of their output as impedance is halved?

Interesting criteria...

 

[robertawillisjr]

So, for a high quality system, one ought to eliminate from consideration any amplifier that does not advertise in their specifications a doubling of their output as impedance is halved?

Interesting criteria...

Well that is a starting point. There are amps that don't meet this "criteria" that work fine but you will need to investigate those before purchase. The Sanders amp doesn't double down but it was made for electrostatic speakers.

Often a speaker that doubles down is a will handle ELS impedances. That is not to say that they will sound good.

 

[Dominick22]

Just another option. I run the Ascent i's and if I could afford it, I would get the mcintosh 500 watt monos.

Since that is getting too pricey for me, I settled for the Emotiva 1,000 watt monos that cost $1,000 per unit. Anyway, I saw that you had mentioned spending $3k. You might want to check out Emotiva. I am happy with them. The amps also have a simple meter on the front that will let you know when the amp is being driven to the point of clipping. Sounds like you could use this. I have had my speakers very very loud....to the point that it physically hurts my ears and while the led power meter is bouncing around like crazy...I have never made the amps go into clipping.

Also, the are very good about posting every specification you could possibly want to see in shopping for a amp.


Good Luck,
Dominick

 

[Solo]

An old thread, I know, but in the event that someone else wanders by here with the 5800 question: I've used an Adcom 5800 with my Quests for many years and played them at all volume levels, all types of music. I've never heard any distortion except for when the bias levels were not properly adjusted in the 5800. It's not impossible that the original poster had a problem with his 5800.

 

[gordonmenninger]

I would also suggest the Pass amps and my favorite and personal choice are any of the Krell amps. THey have no problem playing down to 1 hz and sound magnificent! I personally have a KSA300S amp that is a beast but others will do as well. Audiogon / ebay are your friend on these!:rocker: