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AMP A / B COMPARISONS - Page 2

post #16 of 500
Quote:
Originally Posted by milosz View Post





Pics of what?  The various amps' insides?

 

Yeah I could do that, sure- are you interested in that?





Pics of your a/b box construction - sorry, shoulda been a bit more specific
post #17 of 500

I say.... keep posting pics each time you do a comparison! (if its not too much to ask) Thanks!

post #18 of 500

thanks nice comparisons..

post #19 of 500

How are these 'phones if you don't use an amp at all?

 

Lookin' forward to the tube comparisons.

post #20 of 500
Quote:
Originally Posted by miloxo View Post

How are these 'phones if you don't use an amp at all?

 

Lookin' forward to the tube comparisons.



I too thought that an amped vs unamped comparison would be interesting:)

post #21 of 500
Thread Starter 

 

Sixth A / B comparison:  Beta 22 & Sugden A25 Integrated amplifier headphone jack (!)

 

Same everything as above. THIS IS NOT A SCIENTIFIC TEST.

 

NOTES:

  • Sugden A25 is a mid 1980's model, made in England.
  • A25 has MOSFET output stage, lots of film capacitors, epoxy-fiberglass circuitboards, and is either class A or "high A  class AB" depending on your source of information.  It gets HOT so whatever class it is, the idle bias is set pretty high.
  • A25 rated at 29 watts / channel
  • Uses standard practice of resistors in series with amp output for headphone jack
  • I replaced the NE5534 op amps in the gain stage with OPA627ab's (on sockets)
  • This amp is really very nice, sounds nice on my Quad ESL-57's and on other speakers.  Sounds more powerful than 29 watts / side.  Sounds like class A to me.
  • eBay purchase $125 in 2007.
  • I have a schematic for this amp- which is hard to find.  If you need a copy, PM me, I'll be happy to email it to you.

 

LCD-2:  Bass not quite as powerful / authoritative as the Beta-22, but otherwise good bass. Highs a little rolled off compared to the Beta-22, but curiously female vocalist sibilance is more un-naturally prominent or somewhat exaggerated through the Sugden compared to the Beta-22.  High volume setting is required to drive the LCD-2's (50 ohm phones) but good volume level is obtainable.

 

HD800: Again, bass not quite as well controlled or deep as the Beta-22. Some midrange exaggeration from the Sugden, possibly revealing why this amp is supposed to sound a bit "tubelike." Upper highs rolled off a bit with the Sugden compared to the Beta-22, and yet again there is this false emphasis on female sibilance though not as pronounced as it was  driving the LCD-2's.

 

CONCLUSION:  This integrated amp (with upgraded op amp)  sounded pretty darn good, though not QUITE up to the high standard set by the Beta-22.  I did not get that "fatiguing" effect that I got from the Yamaha, which makes me think this amp is either class A or is operating in class A at the level I'm using it at.  Sucker gets QUITE hot! Nice little amp, though.  You don't see too many of these.  Makes a nice bedroom / office speaker amp with possibility of occasional headphone use.  Has a phono preamp.

 

This amp shows to me that headphone jacks in integrated amps can sound pretty decent if the amp is approaching high-end in design (as in class-A operation and quality parts.)  Not as good as a headphone amp like the Beta-22 or the M³, but better than the conventional wisdom holds.

 

Last of my solid state amps, by the way.

 

A25, 1980's British near-high-end.

Sudgen-A25a.jpg

 

 

 

Op amp mod

OPAMP-sockets.jpg

 

Driver transistors and output MOSFETs.

Drivers.jpg


Edited by milosz - 11/16/10 at 4:15am
post #22 of 500
Thread Starter 
Quote:
Originally Posted by miyinan View Post



Quote:
Originally Posted by miloxo View Post

How are these 'phones if you don't use an amp at all?

 

Lookin' forward to the tube comparisons.



I too thought that an amped vs unamped comparison would be interesting:)



Uhhh.... not using an amp?  You mean driving the phones with the line output of my DAC?  I am using a Cambridge DACMagic as the source here, it doesn't have a headphone jack, and I doubt it could drive the 50-ohm LCD-2's, although there would probably be some sound from the HD800's.  But this is not  something that is going to work very well,  people don't generally use a line output to drive headphones, it's not really intended for that.

 

Maybe I didn't understand what you were trying to say....?

post #23 of 500
Thread Starter 
Quote:
Originally Posted by swifttal View Post





Pics of your a/b box construction - sorry, shoulda been a bit more specific


OH, the A/B  box.  OK, I'll put that in here someplace.  Maybe at the end.  Most of these pictures I'm using I already have on file, have to get the camera out for the A/B box.  It's just a pair of headphone cables,  a jack and a DPDT toggle switch in a black Hammond plastic project box.  Nothing fancy.

 

Some might say that the pedestrian headphone cables I'm using for the box moot the comparison, but I would beg to differ because although they are not fancy wires, the same type and length of cable is used for each amp. This rig is supposed to show the differences in sound between two amps on test, and so each amp is connected using the same kind and length of wire. Using much better wire might improve overall results (though I doubt it) but wouldn't change the DIFFERENCES heard between the two amps.  If two amps sound different enough to justify a $500 price difference, I'm thinking you OUGHT to be able to hear that difference EASILY.  I don't know about you, but if I spend $500 or $1000 more for a given headphone amp, I want to hear a SIGNIFICANT difference. $500 is almost real money; it's certainly more than I typically spend when I buy a CAR.  cool.gif

post #24 of 500
Quote:
Originally Posted by milosz View Post



Quote:
Originally Posted by miyinan View Post



Quote:
Originally Posted by miloxo View Post

How are these 'phones if you don't use an amp at all?

 

Lookin' forward to the tube comparisons.



I too thought that an amped vs unamped comparison would be interesting:)



Uhhh.... not using an amp?  You mean driving the phones with the line output of my DAC?  I am using a Cambridge DACMagic as the source here, it doesn't have a headphone jack, and I doubt it could drive the 50-ohm LCD-2's, although there would probably be some sound from the HD800's.  But this is not  something that is going to work very well,  people don't generally use a line output to drive headphones, it's not really intended for that.

 

Maybe I didn't understand what you were trying to say....?



Sorry, I didn't know that you are using the dacmagic which doesn't have a headphone output. I thought that it would be interesting if you do an a/b comparison between your beta22 and the headphone jack of your dac or computer.

 

Lee

post #25 of 500
Thread Starter 

Oh, yes, sure.  Like if I had a Benchmark DAC, they have headphone outputs.

 

Alas, I don't have one of those.

 

Hmm.  Maybe I'll rig up a twin RCA-to-1/4" headphone jack just to try and see what happens when you hang an HD800 right off the DAC outputs.  I suspect it can't drive the HD800's, but I've never tried it, I don't really know.

post #26 of 500
Thread Starter 

 

Seventh A / B comparison:  Beta 22 & modified Musical Fidelity XCAN V 3 amplifier (with Musical Fidelity stock external wall-wart PSU which supplies 24 VAC CT at 500 mA)

 

Same everything as above. THIS IS NOT A SCIENTIFIC TEST. [ By which I mean it is not  a blind test evaluated statistically.  I am switching between A  and B  myself, I know which amp is A and which is B, so psychological factors may lead me to think I hear things that would disappear in blind testing.  Which is to say, if there is a major difference that I head between A  and B, I would guess this would NOT vanish in a blind test, while any subtle differences just might.]

 

NOTE:  The Musical Fidelity XCAN V3 is a hybrid design, having both tubes and transistors in the signal path. The tube runs at a very low B+ of 60 volts, so it is probably NOT the output stage, but a voltage gain stage.  The output stage appears to be a pair of transistors which  appear to be bolted together to couple them thermally.  Look at the photo, they are near the output coupling caps.  The modifications I performed are those widely circulated on the Web:  replace all the electrolytics in the power supply with lower ESR / higher temp rated Panasonic caps, replace the power supply diodes with faster / quieter Schottky types, remove the input DC blocking electrolytic cap altogether and switch out the 470 uF output coupling polar electrolytics with 1000 uF nonpolar types. (The stock caps were already bypassed with film types, I left those film bypass caps alone.)

 

I did some before and after measurements of this amp RE: these mods.  After making the modifications there was about 2 dB lower noise and response at 10 Hz with a 200 ohm load came up about 1 dB, to 0 dB (flat, instead of a slight roll-off at 10 Hz.)

 

HD800: I had some problems get a matching level between the Beta 22 and the XCAN.  When I set the levels using a 1000 Hz tone and a voltmeter, the XCAN sounded a little quieter than the Beta-22.  I determined that the XCAN has a slightly higher level in the midrange than the Beta-22, I didn't take the time to do frequency sweeps but when I set the levels using a 100 Hz tone and a voltmeter, the two volumes now seemed about equal, with the XCAN having just a slightly richer midrange.  So it seems there is a little midrange emphasis from the XCAN.  The XCAN also had somewhat different sounding highs.  This is hard to describe, but I think it was related to the slightly different harmonic profile of the tube stage adding a slight- very slight- amount of euphonious coloration.  Also, the highs didn't sound quite as open or detailed with the XCAN. They didn't sound rolled off, though.  Like I said, the highs are kind of hard to describe, but they were slightly different than the Beta-22.  Bass from the Beta-22 had a tiny bit more weight than the XCAN.  Also, I noticed the XCAN had slightly less channel separation than the Beta-22, and this lead to the sense of space from the XCAN being just a little smaller. Overall, the slightly lower separation, slight midrange emphasis and slightly "sweetened" highs added a feeling of "intimacy" or "closeness to the musicians" that was an interesting voicing, and one which was kind of nice on the HD800s which sounded a little more "clinical" on the Beta-22.

 

LCD-2:  XCAN drove the 50-ohm LCD with power to spare, although I did have to dial up the gain just a little when chainging over to the LCD-2's from the HD800s so I could tell the amp felt the impedance change. In some ways the more "intimate" highs of the XCAN were even more noticeable on the LCD-2, which I thought interesting since the LCD-2's doesn't have the slight treble exaggeration of the HD800's that tend to make changes in highs MORE apparent on the Sennheisers than the LCD-2's, generally speaking.   Well, not THIS time-  here, I could hear the difference in the highs a little more clearly on the LCD-2's.  Bass was, again, slightly deeper from the Beta-22. 

 

The XCAN sounded pretty good, really, in particular it kind of focussed the listener away from the somewhat emphasized highs of the HD800 without actually rolling off the highs a lot and sounding dark.  I might even get to like the XCAN more on the HD800's than the Beta-22. On the LCD-2's I preferred the Beta-22 by a small margin.

 

The XCAN is a fairly attractive unit.  (Put a fancy control knob and a thick aluminum front panel on just about anything and I will probably buy it.)

 

PHOTOS - the case of the XCAN does not open.  Rather, the guts can be slid out.

 

musicalfidelity_X-CAN.jpg

XCAN-b.JPG

XCAN-a.JPG


Edited by milosz - 11/20/10 at 3:40am
post #27 of 500

Thanks for all those mini comparisons (any I hope you keep it up) though i'm finding it so strange reading this thread.
The general opinion online is that beta 22 and HD800 are a
divine combination and that the beta22 is a reference quality amp and a  sure beng-for-buck at arround 1000$. Then you find it marginally better compared to basic hp amps (the FUN, CKK that I also had and the portable RSA).

I don't doubt your words for a moment though you can see why it's hard for me to accept.

 

post #28 of 500
Thread Starter 
Quote:
Originally Posted by eliziz View Post

Thanks for all those mini comparisons (any I hope you keep it up) though i'm finding it so strange reading this thread.
The general opinion online is that beta 22 and HD800 are a
divine combination and that the beta22 is a reference quality amp and a  sure beng-for-buck at arround 1000$. Then you find it marginally better compared to basic hp amps (the FUN, CKK that I also had and the portable RSA).

I don't doubt your words for a moment though you can see why it's hard for me to accept.

 

I totally understand what you are saying.  I am quite surprised myself that I'm not hearing major differences in the sound.  But if you re-read the original and sundry reviews of all these various amps- they are generally reviewed alone, with reviewers having to rely on "audio memory" of what other amps sound like.  They aren't direct A/B comparisons.

 

Make some immediate, direct comparisons yourself and see if you hear any major differences between  amps at your disposal.  It has to be done with an A/B switch, taking the time to move the headphone plug from one amp to another is too long to really be a DIRECT comparison.  I think a lot of us - myself included- are assuming that if it's more expensive it HAS to be better.  Well I would argue that the Beta-22 IS a better amplifier -technically better- than, say, the  M³, but even though it uses superior technology it doesn't SOUND that much different.  There is a difference, but in listening to the two amps in direct comparison for a fairly long listening session, the differences I hear are pretty slight.

 

It's possible that having a switch, and these non-exotic headphone  cables leading from the amps to my switchbox, is somehow masking the differences between these amps.  Although I have to say that the SAME cable type and length is used to connect each amp, and since the same cable & switch is used then the DIFFERENCES between the amps, if any, should still be audible.  And if the difference is so subtle that wire can mask it - well, then it's not really that huge of a difference, is it?

 

I've been involved in audio for a long time, and have worked as a radio producer and in recording studios, and I would say my "critical ear" ability is fair enough to tell if there are substantial differences between two sounds. 

 

After I run through my series of tests, I will pick a few amps and then have a number of different listeners come in and judge them - including some professional musicians, both classical and jazz.  This should help sort out if it's my ears or not. I would also be willing to run some blind tests for any Head-Fi'ers in my area who want to stop by and see if their ears are golden and mine are tin; I live in Chicago and I think there may be some folks here who would take up this idea.  Or maybe at the next Chicago mini-meet or something.

 


 


Edited by milosz - 11/20/10 at 5:44am
post #29 of 500

Thanks a lot. I also find the differences is minor. I need a few  weeks to really get to know the different amps and how they compare to eachother. As you I also noticed bigger changes between my tube amp and my solid states versus different solid state amps. Beta22 seemed to be consistent the top pick?

post #30 of 500
Thread Starter 
Quote:
Originally Posted by oqvist View Post

Thanks a lot. I also find the differences is minor. I need a few  weeks to really get to know the different amps and how they compare to eachother. As you I also noticed bigger changes between my tube amp and my solid states versus different solid state amps. Beta22 seemed to be consistent the top pick?



The Beta-22 is considered to be a very good or excellent amp by all the things I've read, so I am comparing all the other amps to the Beta-22.  Quite a few folks have called it "reference" quality. The Beta-22 is probably the best amp I have so I am using it as the benchmark to listen for differences compared to the other amps I have.

 

I think I will hear much greater differences compared to the Beta-22 with these tube amps which are the next amps in my test:

  • Bijou with "Bugle Boy" 6DJ8's
  • Little Dot MK III, stock tubes
  • Bottlehead Crack w/ Speedball upgrade and film cap output coupling / stock tubes.

 

I think the Bottlehead will have the greatest difference in sound, the most "tubey."  (And I already know it can't drive the 50-ohm LCD-2)

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