Changed amps - center image moved


I recently changed amplifiers from TRL Samson (monos) to Maker Audio Ref 2A stereo amp.  Both amps are superb but using the same associated equipment (DAC preamp, sources, speakers) my center image changed significantly.  I did go from single ended to balanced interconnects.  The Maker has a much wider image (well beyond outside of speaker but the center image is diffuse (not specific).  Also, with the Maker amp, more sound comes directly from the speaker (very little w the Samsons).  The TRL Samsons had a specific center image but more narrow width (very little outside of speaker).   In a perfect world, I would have the specific center image plus the ultra wide space.  Anyone experienced a similar situation and how (were) you able to optimize.  Don't get me wrong though, the Maker is fabulous in every aspect....killer detail without edginess, dynamics that are breathtaking.

Just trying to figure ways to re-attain the center image specificity.  Suggestions?


jeffga
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Are you using any acoustic treatments on the front wall between your speakers? And how far away from the wall are your speakers?
Some absorbtion between the speakers can help with a more focused image, along with distance between the speaker and wall.

Also, heavy rack units between the speakers can cause diffused imaging. Speakers must be pulled forward of the rack or furniture unit.
Mono amps can give more precise image because of an ideal channel separation.
It's your trade I guess.  
New amp would certainly dictate new speaker placement and more experiments: closer or farther from wall; narrower or wider distance and also listening distance too.
Make sure you'll leave it on for at least few days and see if things change after the electronic components settle. 
My experience is that it's not uncommon at all for imaging to change when one changes amplifiers.  If you prefer the imaging you had with the original amplifiers, you may be able to get it back just by repositioning your speakers.  Take time and experiment.
This sounds a little too dramatic to just be attributable to changing amps. It sounds a lot like you have inverted polarity somewhere, which would do exactly what you’re describing to the imaging. I’d go back and check you have all your interconnects and cables properly connected positive to positive and negative to negative. If you do, I’d try reversing the polarity on the amp or speaker side (but not both) and see if things snap back into focus. The other thing to check is if your preamp has an inversion switch you may have inadvertently flipped in swapping equipment.  In any event, this does not sound right. 

One last thought.  Not sure how it would cause this, but I'd go back to my prior interconnects if the new amp has single ended inputs just to take another variable out of the equation.  Good luck.

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Yes, could be polarity especially as you also swapped to XLR as well. it hasn't been unknown for XLR cables to be incorrectly wired. I'd check each one using a multimeter to ensure that none of the connections have been crossed
I ran into the same problem few years ago. AES industry standard for balanced audio XLR wiring, commonly known as "pin-2 hot".

Some manufacturers, especially in vintage equipment, do not follow this standard and instead reverse the polarity of pin 2 and 3.

A reversal of polarity between XLR pins 2 and 3 at some point in the signal path would result in diffuse imaging if and only if it occurred in one channel, not both. Presumably a component design in which pin 3 is the non-inverted signal and pin 2 the inverted signal (which is the opposite of the usual convention in the USA and various other countries) would do that in both channels.

Also, given the reference in the OP to excellent sonics (which would certainly be compromised big-time if a polarity reversal was present in one channel), and the level of sophistication that a user of a Maker Audio product can be presumed to have, I would expect that a polarity reversal in one channel is unlikely to be the cause.

Jeffga, what preamp and what speakers are you using? And is there a subwoofer in the system?

Regards,
-- Al
Check your speaker cables for polarity Jeff. Sounds like a polarity issue. The XLR pins also....may be the issue.
Okay, I often see people advising folks to check polarity when something is wrong with imaging and bass and I have to ask; is it that hard for some people to recognize that their speakers are out of phase?  I swap equipment in and out of my system frequently and occasionally I do hook my speakers up wrong, but I can immediately tell that the system is out of phase before I even get back to my listening chair.  It's a very distinct and immediately recognizable sound.  Do others really have a hard time hearing this?

Thanks everyone!  The XLR cables are from Grover Huffman (very good cables).  I am using a ThetaGen VIII DAC (latest) using its internal preamp.  Speakers are GR Research Alpha LS (highly modded), speaker cables are Amadi's.   Again, the only two things that changed are the amp and going to balanced IC's.  All good suggestions!  Will try the polarity on speaker cables, speaker placement (including toe-in).  I cannot go back to the RCA IC's yet as the Maker amp is XLR input (only) -- however, I have an adapter shipping to me so I can try going back to the previous RCA cables.  Again, the Maker amp does everything great, just wanting a more specific center image. 
I have an adapter shipping to me so I can try going back to the previous RCA cables.
I don’t know whether or not this may be applicable to your Maker Audio amplifier, but I’ll mention that there are some amps having only XLR input connectors which will not work properly when provided with single-ended signals via adapters. Certain Audio Research models for example, which have balanced internal signal paths and provide only XLR inputs, are designed such that if they are provided with single-ended inputs half of their balanced signal path will not receive a signal. Resulting in **greatly** reduced power capability as well as some sonic degradation.

You might want to ask Mr. Maker or one of his associates if that concern applies in this case.

A single-ended signal can be converted to a true balanced pair of signals with a device such as a Jensen Transformer (~ $300) or an SMc Audio Flex-Connect ($1895).

Good luck. Regards,
-- Al


P.S: I took a look at the descriptions and the manual for your Theta DAC/Preamp. The one point I’d highlight after looking at them is that in addition to changing the amp and the cables, by changing from RCA to XLR cables between the Theta and the amp you are now utilizing within the Theta (for each channel) two DAC chips, two volume control mechanisms, and two analog signal paths rather than just one of each of those things that were used previously.

In other words, while the signal applied to the RCA output connector for each channel is produced by the same DAC chip and subsequent analog signal path that provides the signal to one of the two signal pins on the XLR connector (probably pin 2), the other signal pin on the XLR connector (probably pin 3) is provided with a signal produced by a completely different (although supposedly identical) DAC chip and subsequent analog signal path. And that different DAC chip and different analog signal path within the Theta were not in use when you were connecting via RCAs.

You can see that in the block diagram on page 11 of the manual, as well as in the description at the Theta website:

http://www.thetadigital.com/downloads/Generation%20VIII%20Series%203.pdf

http://www.thetadigital.com/generation_viii_series_3_dac_preamplifier_info.shtml

So in addition to the possible causes of the issue that have been referred to previously, the Theta itself cannot be ruled out as a suspect at this point. And if changing the XLR cables to RCA cables + adapters resolves the problem, it would NOT necessarily mean that the XLR cables are to blame. In fact if that turns out to be the case I would expect it to be much more likely that the Theta is the root cause of the problem, rather than the cables, assuming there isn’t an outright miswire in one of the cables (which seems very unlikely given the good sonics you have reported).

Good luck. Regards,
-- Al
Wow Al....many thanks for your interest and help!!  One interesting tidbit...when I had the Samsons, I used a Cardas XLR to RCA adapter at the DAC side (so to get more output via the AES outputs on the DAC & not need a preamp), thus could use RCA IC's.  The imaging was superb.  BTW, I switch speaker leads and imaging improved, though still not the middle specificity on vocals.  However, on classical / orchestral, the Maker soundstage is uncanny.  Wide, deep and specific..this is weird.  Seems vocals and rock music have the issue.  The Maker sounds fantastic, just freaky clarity.  Thanks again..I will report once the RCA's are re-inserted.
I looked at the picture of that amp and I could see myself easily wiring the right speaker in reverse polarity. Every amp I had has the red (positive) speaker terminal to the right of the black or above it. The Maker has them mirrored so it may be possible you wired one speaker out of phase.
2 thoughts.  

Usually going from rca to xlr, soundstage expands, airier.   rca has tighter sound.   Not better but different.  Maybe just hearing the differences.

When I was shopping for SS amp, investigated Maker and found this interesting review.  Maker Audio NL14+   It mentioned imaging outlines weren't as razor sharp so possible amp natural characteristics.   I emailed Tom Maker with questions but never got a response so moved on.   

I had TRL Samsons and it's an excellent amp.  It was 1st SS amp since Krells and NO contest.  Mine had XLR but still a singled design.  Wasn't a good match with new balanced pre so had to move on.


Why is there so much concern about a center image changing with an amp change as though something has to be wrong with the rig? What jeffga has described is typical; every component has its own set of sonic characteristics. The description of more sound coming from the speakers is not out of character for switching amps; some have more of this than others. He didn't say there was a gross diminishment in the sound or that the center image had grown fuzzy, merely that it was more diffuse and larger. That is certainly not a concern as though something is wrong with the setup. 

Having worked with dozens of amps I assure you that such changes are common and to be expected. This is a very regular occurrence for me, and it is not the result of mis-wiring or another problem in the rig. The proper attitude should be to suspect something wrong if one swapped amps and perceptually nothing changed! The interconnects also influence the spatial characteristics of the sound, and moving from RCA to XLR can do so, as well as different brands/models. When you change both amp and cables you had better hear a significantly different sound, or else you have wasted your money/time (Unless the new component/cables are significantly cheaper and result in similar sound quality - but this is rare). 

jeffga, you said, "In a perfect world, I would have the specific center image plus the ultra wide space." I smiled when I saw that. This is the world of the audiophile; when you hear one setup with characteristics you enjoy, then change the rig, you have a shift in system characteristics, some more pleasurable, and some less. Welcome to crafting an audio system! It's an art that sometimes takes a while until you get everything just so. I suggest you revisit positioning, i.e. toe in, of speakers to get a ready solution to the center image, which may get you to the happy compromise sound between size and precision of center image. :) 

What you are experiencing is the amp change . Have had quite a few amps and the way they imaged was different for each one . You should not expect them to be the same ? 
Wow Al....many thanks for your interest and help!! One interesting tidbit...when I had the Samsons, I used a Cardas XLR to RCA adapter at the DAC side (so to get more output via the AES outputs on the DAC & not need a preamp), thus could use RCA IC’s. The imaging was superb.
You’re welcome, Jeff. But I’m wondering about a couple of things in regard to this statement, if I am correct in interpreting that you were using XLR-to-RCA adapters on the analog outputs of the Theta DAC/Preamp:

1)Using XLR-to-RCA adapters on the XLR analog outputs of the Theta would not have given you any increase in output, compared to using the RCA outputs. As I mentioned earlier the RCA output connector is wired directly to one of the signal pins on the XLR connector, and it is that signal which would have been provided to the Samson via the adapter. The other signal on the XLR connector would not have been used. The reason the XLR output is specified as having twice the voltage of the RCA output is that the spec for the XLR output reflects the use of both signals.

2)More importantly, most XLR-to-RCA adapters short the unused signal (usually pin 3) to ground (pin 1). My understanding is that Cardas adapters can be special ordered to leave pin 3 unconnected. While shorting pin 3 to pin 1 is proper practice for adapters that are used on inputs, with most designs it is definitely something that should be avoided on outputs. Do you know if the Cardas adapter you used shorts pin 3 to pin 1? If you are uncertain that can be easily determined with a multimeter, if you have one.

If that adapter shorts pin 3 to ground (pin 1), given the extremely low output impedance of the Theta (25 ohms balanced, corresponding to about 12 ohms for each of the two signals in the balanced signal pair), a concern would be that over time the short might have adversely affected the health and the performance of the Theta’s analog output circuit which drives pin 3. And if so, that could conceivably account for the imaging issue, since the pin 3 output is now being used (while not having been used when you were connecting to the Samsons).

In any event, good luck as you proceed. Regards,
-- Al


Guys it is possible one speaker has been hook up with the leads reversed. This will in fact cause such a sonic character. This is a reasonable course of action. Kind of simple...right? If not the cause, then yes the amp sounds different with the speakers. Small speaker placement changes may also help if not a polarity issue. 
Guys it is possible one speaker has been hook up with the leads reversed. This will in fact cause such a sonic character.
Bill, yes it will, but as I and Seikosha indicated it will also cause big-time sonic degradation, which the OP has indicated multiple times is not occurring. Although as you indicated it’s easy enough to check, and it is certainly something that should be checked.
If not the cause, then yes the amp sounds different with the speakers.
Not necessarily. The Theta DAC/Preamp is also suspect, as I explained in my previous posts. He is now using a signal path of the Theta that was not used with the previous amp. And furthermore he is now using an output circuit of that previously unused signal path that may have been shorted to ground over a prolonged period of time, and whose condition is therefore highly questionable.

Best regards,
-- Al

Yes that also Al. The point is these are all valid points and will in the end sort out the end facts. A system can still sound "good" subjectively out of phase on one or both speakers. I have experienced it. 
It is also possible that the amp itself could have one channel wired out of phase with the other. With balanced equipment this is very easy to do by mistake!

I would reverse the speaker connections on one channel only just to see what happens. Does the center image improve? Is there less information sitting in the speakers and more spread out between them? If so, then we will know that there is indeed a phase problem, and the next step will be to find out where it is.
All great suggestions and comments.  It is true that changing amps can/will change the sonic characteristics.  It is, in fact different.  Better in most ways.  I was simply wondering if anyone had experienced a similar imaging change and was able to affect it by doing certain things (like you guys are suggesting).  I will continue experimenting.  BTW, both the TRL and Maker amps are killer.....and I have owned quite a few in my day.  Thanks again!
Great point Ralph, I once owned an amp that was built with one channel wired out of phase. Opened up the amp and quickly figured out that was the issue. 
I've had several instances after I've made significant upgrades that I've had to re-position my speakers to allow for a change in soundstage height or width.
I find a diffuse center image is often 'fixed' by using cones beneath the amp. One amplifier I reviewed came with Audioquest Bigfeet (sorbothane) and I felt the imaging was quite non specific.The designer told me that was his intention as it is more like a real concert experience he said. Well I record with single point mics and the imaging is very specific when the system permits. I consider myself an image freak basically as I have experienced a lot of live music over the years and to me this heightens the reality of reproduction considerably.
 Now another more expensive model amp of the same brand came with Stillpoint feet which I liked more and they imaged fantastically but were also monoblocks. When I put a set of polycrystal cones beneath the less expensive amp I found the image far more focused which is the effect I hear when using cones under my gear. I like to use squishy feets under transports as these create vibrations but I use Black Diamond Racing cones and Brightstar brass cones too. I find I can tune the bass dampening with these but then I also experiment with the material they are placed on and  I have used glass, rubber, concrete, and hardwood beneath my components as my ears inform me. Some of the better stands offer shelves of different materials so I am not alone.
 Sometimes it is the chassis itself and mass loading works wonders. I like to use aquarium stones which come in an nice bag. Sand is just too deadening. The $2500 amp had a rather flimsy top as opposed to the 5X more expensive model that was hewn from a solid billet, which is why you see this done on many high end electronics. On occasion I directly damped the circuit board with small pebbles (remember the diamond dust filled YBA gear or Shun Mook dots?).
 Balanced inputs usually also have additional buffer stages or transformers than do the single ended ones that I find degrade the sound. Check out schematics if you can I am not making it up. They just create the phase flopped output leg in most cases and buffering. However true symmetrically balanced circuits which are very rare do indeed perform better with a balanced input but then the preamplifier must also be true balanced. On my Tascam DV-RA1000 optical disk recorder the balanced input runs thru more than 3 additional opamps then does the unbalanced inputs for instance. Same with my Nakamichi MR-1 ins and outs. Balanced lines are designed for long runs that require common mode noise rejection. Not ever needed in any of my audio systems but you bet my microphones are all balanced lines. YMMV
Returned from Mexican vacation and the adapter arrived.  First I simply reversed polarity on one speaker...improved center image (using the XLR cables).  Then, switched to RCA IC's with the adapters (at amp only).  This fixed the problem!!  Perfect center image and huge depth in soundstage.  RCA out of Theta (no adapter) to Maker amp with RCA to XLR adapter......sounds fabulous!  The Maker amp is great.
Outstanding!

So it sounds like there were two problems that were simultaneously present. One of them being reversed polarity on one of the speakers, and the other being suggestive of a defect in one of the two signal paths to one or both of the balanced outputs of the Theta, as I had speculated. That signal path not having been used when you were connecting to the previous amp, and the problem perhaps having been caused or contributed to by the XLR-to-RCA adapters you were using at the Theta’s XLR outputs when you were connecting to the previous amp.

In any event, congratulations on the new amp and enjoy! Regards,
-- Al

The next step is to get rid of the adapters, perhaps having the XLRs installed on the ends of your existing cables.

I find that adapters often eat some of your dynamic impact, and its an easy thing to fix.
Jeff, you seem to like the amp more than the Samsons? Tell me how they differ please. Those TRL amps were very good indeed. Happy for you.