Audio Madness! I am going to go crazy...

[Seth=L]

Rant to ensue, prepare yourself for nonsense.

First, and this has nothing to do with audio, I can't upload a picture to show you the equipment I'm dealing with. That's frustrating but I'll manage to continue without.

Second, I thought I would do a little upgrade in my bedroom system. My bedroom system is comprised of a pair of M&K S-80 satellite speakers, a Paradigm PDR-10 subwoofer, a Teac CR-H220 CD/Receiver, and a Sony DVP-S7700 as my CD player. I have the Sony connected to the Teac via some old StraightWire interconnects I've had from my "audiofool" days. Say what you will about those cables, but they've held up longer than anything else I've had. Now the snag. I figure I could benefit from some extra headroom so I bring my Teac A-1D from the living room and replace the CR-H220 with it. Now the CR-H220 has a built in 25 watt per channel amplifier, that's a ambiguous rating at 6 ohms and 1kHz test tone, not even sure if that's both channels driven. The A-1D is rated 50 watts RMS per channel 8 ohms 20Hz-20kHz and even more at 4 ohms.

I immediately became enthralled with anger as soon as I turned it on and music started to come out of it. I double checked to be sure the polarity was correct despite the fact I was getting a very strong center stage effect. I was listening to Depeche Mode. I've listened to this album many times in the bedroom setup with the CR-H220 in the A-1D's place. Now with the A-1D the sound is just barely leaving the confines of the two black boxes known as the M&K S-80. I get a center stage and a very otherwise not exciting sound. The CR-H220 sounds exponentially more open. The CR-H220 has no gimmick that makes some "simulated surround" so I can't help but think "what gives?".

So I switch back to the CR-H220 to see if I'm losing my mind right, what sane person wouldn't? Well to expedite switching back and forth between the CR-H220 and A-1D I decided to terminate the bare wire with some odds and ends banana plugs I have around the house. Luckily I had another set of StraightWire interconnects and the DVP-S7700 has twin sets of stereo RCA outputs. I get the CR-H220 hooked back up and it's on for about 15 seconds playing music and I go to sit down and listen.

ENTER PROBLEM #3 As soon as I sit down the sound from the right channel cuts out. Instantly I see red and several angry curse words escape my mouth that arrive in no particular order and make absolutely no sense, much like I view the problem I suddenly am having with the CR-H220. Was the little half width Teac cursing me from attempting to replace it? Did it say "fine, you don't think I'm good enough? I will show you!"? Apparently the stupid little banana plug was the cause of the problem because once I illuminated it the problem seemed to disappear.

So my process of switching between the two is going to lengthen and I worry about that length of time between switching causing more bias thus rendering me unable to determine if I truly losing my mind. I had fully anticipated the A-1D sounding exactly the same as the CR-H220, just with the ability to go louder and I find myself utterly frustrated when I believe to be hearing inferior sound from the much bigger and more mature A-1D. The A-1D sounded fine in the living room on the Infinity IL10s.

I know there is no way anyone can explain to me why I'm experiencing this, it's making me wonder though. Maybe these two pieces of equipment do sound different somehow.

 

[Seth=L]

The CR-H220 is being used again. I don't know how, it just lets the speakers produce more of a sound stage.

 

[Seth=L]

Meh, nobody cares as per usual. LOL

*I stand corrected!

 

[BoredSysAdmin]

Try different source with A-1D.
Maybe it has an issue

 

[PENG]

Seth, if you have completed your process of elimination and concluded the difference in sound is caused by the two amp/receivers then I would say they do sound difference. First of all, without knowing their design and full specs, even when brand new it is possible they would sound difference. It they are very old, such as >20 years, then it very possible one or both of them have aged to the point they would sound quite different from when they were new. I don't think you should be too surprised.

 

[ski2xblack]

Seth, your experience is similar to what I had recently when re-habbing an old amp. A few genuine oddities combined with too much ocd type thinking on my part led to a lot of confusion and fluctuating satisfaction. It goes away if you keep your head on straight.

In my case, the re-hab helped me appreciate a few things about the old gear (the huge power supply, the wildly over spec'd-and expensive-output devices, etc.), and the knowledge that it performed very well on the test bench help my expectations jibe w/ reality.

I have a pair of M&K mps1510, very similar to yours in many regards. They're still pretty decent speakers, too. I'm pretty sure our speakers use the same 4 ohm woofers, and are low sensitivity (~86db/w, maybe even less), so it could be that you're running both of the amps in the red, where audible differences are more likely to occur. I don't particularly find it odd that you liked the one that would be more in the red, if that is in fact happening. Just a guess at what's going on.

See, some folks do care! Hang in there.

 

[AcuDefTechGuy]

The A-1D sounded fine in the living room on the Infinity IL10s.

The A-1D amp still sounds good with the Infinity speakers when you switched back?

 

[Seth=L]

The A-1D amp still sounds good with the Infinity speakers when you switched back?

I haven't switched it back yet. I'm still using the AG-L800 out there, which I'm not completely satisfied with (it just has some operative limitations).

I'll come back and post in a few, at work and lunch just got here.

 

[AcuDefTechGuy]

at work and lunch just got here.

Oh, man I just ate some Angel Hair Seafood Pasta in my office. Wow, it was delicious!!!

 

[Seth=L]

Try different source with A-1D.
Maybe it has an issue

I wouldn't think it would. The same source works fine with the CR-H220.

 

[BoredSysAdmin]

Nvm

 

[Seth=L]

Seth, if you have completed your process of elimination and concluded the difference in sound is caused by the two amp/receivers then I would say they do sound difference.

You may be right about that.

First of all, without knowing their design and full specs, even when brand new it is possible they would sound difference.

Without getting to responding directly to the next post as it concerns the power limitations of either of these units. The A-1D has a much bigger power supply and will go louder without strain than the CR-H220 without question. The A-1D has discrete output devices and a nice hefty heatsink to displace heat, thing runs quite cool. The CR-H220 has a puny supply and relies on an integrated circuit chip amplifier, class A/B just like the A-1D, and just like the A-1D has an ample heatsink to relieve heat allowing the CR-H220 to run just as cool as the A-1D. Loaded or idle both amps stay cool.

If they are very old, such as >20 years, then it very possible one or both of them have aged to the point they would sound quite different from when they were new. I don't think you should be too surprised.

Both are from the early 2000's, I'd wager the A-1D has a fair amount more use on it. I bought both used and the A-1D was formally owned by a church or school. It just alarms me how much more open the CR-H220 sounds with the same source.

 

[Seth=L]

Seth, your experience is similar to what I had recently when re-habbing an old amp. A few genuine oddities combined with too much ocd type thinking on my part led to a lot of confusion and fluctuating satisfaction. It goes away if you keep your head on straight.

Maybe my head was not on straight, who knows. I did say "audio madness".

In my case, the re-hab helped me appreciate a few things about the old gear (the huge power supply, the wildly over spec'd-and expensive-output devices, etc.), and the knowledge that it performed very well on the test bench help my expectations jibe w/ reality.

The thing is I never would have noticed inferior SQ from the A-1D if I had not placed it in the same setup.

I have a pair of M&K mps1510, very similar to yours in many regards. They're still pretty decent speakers, too. I'm pretty sure our speakers use the same 4 ohm woofers, and are low sensitivity (~86db/w, maybe even less), so it could be that you're running both of the amps in the red, where audible differences are more likely to occur. I don't particularly find it odd that you liked the one that would be more in the red, if that is in fact happening. Just a guess at what's going on.

I was running at very low volumes, chamber music levels. I don't think either was anywhere near red lining.

See, some folks do care! Hang in there.

Aw, thanks!

 

[Seth=L]

Nvm

No sweat, it was a lot to read.

 

[PENG]

The A-1D has discrete output devices and a nice hefty heatsink to displace heat, thing runs quite cool. The CR-H220 has a puny supply and relies on an integrated circuit chip amplifier, class A/B just like the A-1D, and just like the A-1D has an ample heatsink to relieve heat allowing the CR-H220 to run just as cool as the A-1D. Loaded or idle both amps stay cool.

If both are in top conditions then I would agree the A-1D should sound better. How audible the difference is would obviously depend on a few things.

Both are from the early 2000's, I'd wager the A-1D has a fair amount more use on it. I bought both used and the A-1D was formally owned by a church or school. It just alarms me how much more open the CR-H220 sounds with the same source.

So they are not that old, but could still have aged if heavily used by the previous owners. I used to have more faith in used and older amps but recently I have found that my old Marantz preamp and a Carver power amp have lost their edges. The preamp has major roll off in the high frequencies and the power amp has slight but audible (under certain conditions)distortion. The preamp sounds really warm and sweet and I bet in a blind test a lot of people would still think it sounds great and better than my much newer Cambridge Audio fully differential preamp. The old power amp sounds audibly worse than my 10 year old Denon receiver in a crude A/B comparison. I think if one is to pay good money for an older amp, do something to make sure it still meet the original specs, but it is much easier said than done as not everyone has the measuring instruments and/or knowledge and skill to do it. Obviously to a large extent one can just do it by ears, if done carefully.

 

[Goliath]

So my process of switching between the two is going to lengthen and I worry about that length of time between switching causing more bias thus rendering me unable to determine if I truly losing my mind

Time delays are the least of your worries.

A possible level mismatch could account for the subjective audible difference you experienced. That alone is enough to invalidate your experience, but there is another possible (and very likely) influence - sighted bias.

Controlling neither sighted bias, unconscious expectation nor level-matching is enough to create the false impression of audible differences.

I had fully anticipated the A-1D sounding exactly the same as the CR-H220, just with the ability to go louder and I find myself utterly frustrated when I believe to be hearing inferior sound from the much bigger and more mature A-1D.

If your listening was done sighted then you may have biased yourself into hearing a false difference for any number of reasons. But unless you level-matched, you would be pretty much guaranteed to hear a difference even if you compared the same amplifier to itself.

I know there is no way anyone can explain to me why I'm experiencing this, it's making me wonder though. Maybe these two pieces of equipment do sound different somehow.

I've already presented two good reasons that account for your experience :

1) Level mismatch - if you did not account for this, you would subjective think something sounded different and hence your findings would be inconclusive.

2) If your listening session was done sighted then you've pretty much invalidated the outcome of your testing from the start. Bias, both known and/or unknown (conscious and/or unconscious) may have influenced what you heard.

With all due respect, without any controls in place your evaluations don't have any merit whatsoever. Time delays simply exacerbate the issue further.

 

[ski2xblack]

Maybe my head was not on straight, who knows. I did say "audio madness".

When you perceive differences but cannot put your finger on the reason why, it is maddening. I suspect you're probably already aware of the things that Goliath pointed out, and a little reminder never hurts. Keeping that sort of thing in mind is part of keeping your head on straight, otherwise you could end up pulling your hair out in frustration.

But you mention "openness" or sound staging. That is typically the result of quality source material, speaker orientation to the listener, and room interaction. If one of the amps is bad it would certainly adversely affect things. If you could pull off a quick switched AB comparison (difficult), or get the amps on the bench for testing (also difficult if you don't have the tools and knowledge yourself, as qualified, affordable audio component techies are few and far between), you would know more and not be driving yourself mad. If you can't do any of that, I suggest you listen to the one that satisfies the most, kick back, and just enjoy the music. You've got bigger fish to fry, like what music selection to listen to next.

Also, I did a few back of the napkin calculations, and if my assumptions on your speaker sensitivity are close (86db/w, which could be generous as I mentioned up-thread) and distance (I used 8'), the 25 watt amp should hit clean up to 95 db or so, which is quite loud. So I agree, you're probably not running it in the red for polite chamber music, but you have very little margin for less polite levels. M&K's have always been the sort of speaker that didn't mind being flogged with a bit of power, given their low impedance and sensitivity. (FWIW, transient clipping is generally not a huge deal and wouldn't likely affect openness or sound stage unless occurring at gross levels, where the effects would be intolerable in a multitude of ways. I'm just a fan of more than enough amplifier headroom, to reproduce transient peaks in all their glory.)

 

[RichB]

With all due respect, without any controls in place your evaluations don't have any merit whatsoever. Time delays simply exacerbate the issue further.

All products should be purchased blind-folded. A handler should guide you into the room and equipment should be switched by an impartial source that is not allowed to speak and should have no discernable odor.

Of course, this will also be invalid since it will not be in your home.
Completely invalid as well.


-Rich

 

[Goliath]

All products should be purchased blind-folded.

LOL.

 

[Seth=L]

With all due respect, without any controls in place your evaluations don't have any merit whatsoever. Time delays simply exacerbate the issue further.

You may well be correct, but I do find it improbable. The difference was dramatic. I might run another experiment again this evening if I am patient enough to do it.