What causes reduced spatial ambience?

Nelson Bass · 19th March 2012, 08:56 PM

I built me an amplifier based on the J2 concept and used matched JFETs and so on. The amplifier is overall awesome!

I love it!

In my system this amplifier provide lower sense of room ambience compared to an Atma-Sphere S30 OTL (2 dB feedback).
The two amplifiers is comparable for everything else on my speakers (the JFET amp do have better bass grip though).

As I own the JFET amp and not the OTL I want to improve my amp (you know... the first fix was free and I really need that fix - now!

)

So... What can cause the reduced spatial ambience? Feedback? Capacitance in PSU?

a.wayne · 19th March 2012, 09:04 PM

Atmas-phere will have bigger halo sound due to hollowstate devices, may i suggest the use of some headphones, fed from direct source and see which is closer or which is effects box ...

SY · 19th March 2012, 09:17 PM

An OTL will have a high output impedance, so unless your speakers have a perfectly flat impedance curve (and they likely don't), the frequency response will be different between the two different amps.

Nelson Bass · 10:52 PM

Quote:

Originally Posted by a.wayne

Atmas-phere will have bigger halo sound due to hollowstate devices, may i suggest the use of some headphones, fed from direct source and see which is closer or which is effects box ...

Thanks, I've no headphones.
I find the OTL to be very neutral (whatever that is) and as detailed as the J2 variant I built but with better sense of the room by having more air around acoustic instruments on good recordings (like Jazz at the Pawnshop).
I like to hear the same from my SS amp...

My primary PP tube without feedback does not provide the great sense of spatial ambience either.

Nelson Bass · 19th March 2012, 10:47 PM

Quote:

Originally Posted by SY

An OTL will have a high output impedance, so unless your speakers have a perfectly flat impedance curve (and they likely don't), the frequency response will be different between the two different amps.

I'm aware of that but does that cause better sense of ambience?

holminator · 19th March 2012, 11:06 PM

try a resistor between amp and speaker to lower the damping factor of the ss amp.

SY · 19th March 2012, 11:15 PM

Quote:

Originally Posted by Nelson Bass

I'm aware of that but does that cause better sense of ambience?

It will certainly change the sound; how your ears/brain interpret that is something only you can find out.

Floric · 19th March 2012, 11:23 PM

Hi,

made similar experiences, always wondering where it came from.

Quote:

Originally Posted by Nelson Bass

(the JFET amp do have better bass grip though).
:

Any other tonal differences? Those affect the spatial perception very much.

Regards

Nelson Bass · 19th March 2012, 11:38 PM

Thanks, I'll add the resistors and report back.

At first I found the J2 variant to have too much presence in the treble area but got used to it. The midrange area is gorgeous via both amps.

a.wayne · 19th March 2012, 11:51 PM

What speakers are you using .... ?

19th March 2012, 08:56 PM	#1
Nelson Bass diyAudio Member Join Date: Sep 2009 Location: Aarhus, Denmark	What causes reduced spatial ambience? I built me an amplifier based on the J2 concept and used matched JFETs and so on. The amplifier is overall awesome! I love it! In my system this amplifier provide lower sense of room ambience compared to an Atma-Sphere S30 OTL (2 dB feedback). The two amplifiers is comparable for everything else on my speakers (the JFET amp do have better bass grip though). As I own the JFET amp and not the OTL I want to improve my amp (you know... the first fix was free and I really need that fix - now! ) So... What can cause the reduced spatial ambience? Feedback? Capacitance in PSU? __________________ "People can't do what they should: room acoustics and speaker design - so they do what they can: new amps, cables etc." (Lidia)

19th March 2012, 09:17 PM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	An OTL will have a high output impedance, so unless your speakers have a perfectly flat impedance curve (and they likely don't), the frequency response will be different between the two different amps. __________________ If there's a sucker born every minute, where do the rest of them come from?

19th March 2012, 11:38 PM	#9
Nelson Bass diyAudio Member Join Date: Sep 2009 Location: Aarhus, Denmark	Thanks, I'll add the resistors and report back. At first I found the J2 variant to have too much presence in the treble area but got used to it. The midrange area is gorgeous via both amps. __________________ "People can't do what they should: room acoustics and speaker design - so they do what they can: new amps, cables etc." (Lidia)

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19th March 2012, 09:04 PM	#2
a.wayne diyAudio Member Join Date: May 2008 Location: Front Row Center	Atmas-phere will have bigger halo sound due to hollowstate devices, may i suggest the use of some headphones, fed from direct source and see which is closer or which is effects box ...

19th March 2012, 11:06 PM	#6
holminator diyAudio Member Join Date: Feb 2010 Location: Oslo	try a resistor between amp and speaker to lower the damping factor of the ss amp.

19th March 2012, 11:51 PM	#10
a.wayne diyAudio Member Join Date: May 2008 Location: Front Row Center	What speakers are you using .... ?

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