4 Ohms with BasX TA-100

[nussey]

Hello Everyone!

I have been looking at the new BasX TA-100 integrated amp, and I just wanted to ask if anyone here had any information on how the amp stage might compare to the old Mini-X A-100. I assumed (possibly incorrectly) that the amplifier stage of the new TA-100 integrated would be essentially the same thing as the new BasX A-100 amp that has yet to be posted on the website. I also assumed that the new A-100 would be very similar in performance to the old Mini-X.  However, the new TA-100 is quoting 1% THD into 4 ohms. Normally, I don't set too much stock in specs, but that seems to be in the range that even the non-audiophiles out there would notice.

This would seem to indicate that the amp stage is not the same quality as the dedicated amp that came before it (which would honestly make sense given the incredibly affordable  price point of the integrated), or am I misunderstanding something? 

[Deleted]

They used to spec the a-100 at 75 watts at 4ohm with better the. I would guess this is just marketing but I used it with 4ohm speakers and it worked great.

[bootman]

I think the OP's assessment is spot on.

[Deleted]

I agree with the OP.

1% THD into 4 ohms is considered clipping.  4 ohm performance is usually slightly higher than the 8 ohm spec.

50 watts RMS per channel (20 Hz – 20 kHz; THD < 0.02%; into 8 Ohms).
90 watts RMS per channel (1 kHz; THD < 1%; into 4 Ohms).

They spec 0.02  THD into 8 ohms (20-20,000) and then go way up to 1% into 4 ohms (1kHz)

I would rather see the THD @ 0.1 % into 8 ohms and THD @ 0.2% or so into 4 ohms. 

 

[Boomzilla]

The THD may be inconsequential; 1% is likely not audible. I'd agree that the BASX TA-100 might not be a BEST choice for 4-ohm loads, but I doubt that it's a bad choice. I have no idea what THD my Heathkit 12 watt tube amps put out, but it's probably more than 1% - and they sound glorious!

Boom

[rbk123]

Agree. I would put zero stock (concern) into that THD measurement.

[garbulky]

Well 1% - at least from solid state is audible. But it doesn't actually mean that the amp is doing 1% THD through its regular operating spec. All Emotiva amps have very low distortion specs. But at the point of clipping, the distortion rises very fast. So this measurement was simply taken at that point to report higher figures. But that doesn't mean the four ohm performance is much worse or something.

[Deleted]

Sept 2, 2016 4:59:10 GMT -5 Boomzilla said:

The THD may be inconsequential; 1% is likely not audible. I'd agree that the BASX TA-100 might not be a BEST choice for 4-ohm loads, but I doubt that it's a bad choice. I have no idea what THD my Heathkit 12 watt tube amps put out, but it's probably more than 1% - and they sound glorious!

Boom

Tube amp distortion is traditionally not as audible as that from SS amps.  (Or maybe as gzubeck more correctly below says tube distortion is less noticeable/irritating the ear.)

[gzubeck]

Sept 2, 2016 15:58:08 GMT -5 @tllfkacn said:

Sept 2, 2016 4:59:10 GMT -5 Boomzilla said:

The THD may be inconsequential; 1% is likely not audible. I'd agree that the BASX TA-100 might not be a BEST choice for 4-ohm loads, but I doubt that it's a bad choice. I have no idea what THD my Heathkit 12 watt tube amps put out, but it's probably more than 1% - and they sound glorious!

Boom

Tube amp distortion is traditionally not as audible as that from SS amps.

Even order vs odd order distortion. Tube distortion is more pleasing to the ears...

[Deleted]

Sept 2, 2016 11:30:30 GMT -5 garbulky said:

Well 1% - at least from solid state is audible. But it doesn't actually mean that the amp is doing 1% THD through its regular operating spec. All Emotiva amps have very low distortion specs. But at the point of clipping, the distortion rises very fast. So this measurement was simply taken at that point to report higher figures. But that doesn't mean the four ohm performance is much worse or something.

It is doing 1% THD at the power referenced, obviously lower THD at lower power.  So why is Emo or any other brand using 1% THD as a published spec?  I've not seen that before in a Emo amp spec.  It is either a mistake or as you mention, simply taken at that point to report higher figures.  They should not IMO use 1% clipping as their primary power THD spec unless it is clearly listed as clipping. Obviously it works as some above are apparently fooled or simply don't understand amp power specs..  If I have 4 ohms speakers, I want to know the THD into 4 ohms at an acceptable level of THD, such as 0.1% to 0.25%, not clipping.  Some Magazine tests show THD at 0.1 (common THD test level) and then sometimes at 1.0% clipping level for good to know info.  I hate to see Emo fudging on 4 ohm specs (or even not listing them) like many modern AVR amp's and newer low price power amp specs. 

[garbulky]

Hmm...I see what you are saying but at this point it's the level of conservative reporting. I wouldn't like it for say their more expensive units - but this all in one units - meh. But at this level they are not fudging. They are clearly saying the THD level and it's for all channels driven, I assume. Though don't get me wrong - the point is to be able to publish a higher number.

However, This imo is much better than when they tried to call the bas-x 700 a 110X7 amp which is easily intepreted as an amp that can do 110 watts per channel no matter what(all channels driven). But luckily... they re-did the way it was reported to a more respectable figure.

[Deleted]

Sept 2, 2016 16:35:33 GMT -5 garbulky said:

Hmm...I see what you are saying but at this point it's the level of conservative reporting. I wouldn't like it for say their more expensive units - but this all in one units - meh. But at this level they are not fudging. They are clearly saying the THD level and it's for all channels driven, I assume. Though don't get me wrong - the point is to be able to publish a higher number.

However, This imo is much better than when they tried to call the bas-x 700 a 110X7 amp which is easily intepreted as an amp that can do 110 watts per channel no matter what(all channels driven). But luckily... they re-did the way it was reported to a more respectable figure.

"But that doesn't mean the four ohm performance is much worse or something."    Yes it is.  Why not use a reasonable level of THD?  Do you think most folks even know that 1% is clipping or notice it? 

[gzubeck]

Sept 2, 2016 16:35:33 GMT -5 garbulky said:

Hmm...I see what you are saying but at this point it's the level of conservative reporting. I wouldn't like it for say their more expensive units - but this all in one units - meh. But at this level they are not fudging. They are clearly saying the THD level and it's for all channels driven, I assume. Though don't get me wrong - the point is to be able to publish a higher number.

However, This imo is much better than when they tried to call the bas-x 700 a 110X7 amp which is easily intepreted as an amp that can do 110 watts per channel no matter what(all channels driven). But luckily... they re-did the way it was reported to a more respectable figure.

Also, they're saying it's less than 1% at 90 watts... So if your cruising along between 15 -30 watts it's not a factor. I guess what we really need is the distortion curve so that we can actually see where it starts to really start distorting...usable watts vs clipping.

[garbulky]

Sept 2, 2016 16:42:41 GMT -5 @tllfkacn said:

Sept 2, 2016 16:35:33 GMT -5 garbulky said:

Hmm...I see what you are saying but at this point it's the level of conservative reporting. I wouldn't like it for say their more expensive units - but this all in one units - meh. But at this level they are not fudging. They are clearly saying the THD level and it's for all channels driven, I assume. Though don't get me wrong - the point is to be able to publish a higher number.

However, This imo is much better than when they tried to call the bas-x 700 a 110X7 amp which is easily intepreted as an amp that can do 110 watts per channel no matter what(all channels driven). But luckily... they re-did the way it was reported to a more respectable figure.

"But that doesn't mean the four ohm performance is much worse or something."    Yes it is.  Why not use a reasonable level of THD?  Do you think most folks even know that 1% is clipping or notice it? 

I think it's noticeable. When we say reasonable we have to talk about according to who. This is an integrated after all....


What I meant by that statement 4 ohm is much worse is that it's not 1% across the board at say 50 watts or something. It's 1% where it rises quickly to clipping - at about 90 watts. So it's not necessarily WORSE than say a mini-x which probably was rated at 0.1% at a more realistic lower value. It's Emotiva's way of saying this is how much our amp can put out before it sounds iffy. Not that it's iffy at 4 ohm output.

P.S. : I don't think the 1% thd is a good thing. I think it's forgivable that's all.
P.S.S.: My whines are more when it's flat out wrong to post say that 110 X 7 spec that lots of receivers do. Just because other receivers do it, doesn't mean it's okay to deliberately mislead.

[Axis]

I can not picture this amp distorting when using it for the purpose it is intended to be used for. This is not a XPR amp but even if they are hooked to a pair of the new Airnotiv T1's that are 4 ohm and not over pushed they should sound great. Rory has said as much and does anyone think he his going to recommend the TA-100 for the T1's if they did ? He would catch hell if the TA-100 distorted with the T1's and word got out Rory said that its a good match. Just do not max it out with them. That is not proper use of a small amp with hungry speakers.

[Deleted]

So then Emo should just post specs for all their amps at both 8 and 4 ohms at 1% clipping, right?

They use very tight specs for the TA-100, 50 watts RMS  into 8 ohms, 20-20kHz at 0.02% THD.  That is like high end specs!   Is this a mistake and did they actually mean 0.2%?  If they had used 0.1% (0.02 is 1/50th of 0.10, why such extremely low THD%) it would have been higher than 50 watts. also if like many brands they had used 1kHz it would also have been higher.

I'm just surprised and rather confused as why they go from such a stringently low distortion at 8 ohms then go all the way to clipping at 4 ohms.  It just doesn't make any sense to me and perhaps is just a proof reading error.   

I'm not trying to be nit-picky here but amp specs are meaningful to me and I think Emp should be very careful when they post their specs.  I for one carefully check published amp specs.  I was recently trying to help someone with the TA-100 and immediately was surprised when I saw this apparent at least to me discrepancy in the 8/4 ohm amp specs.

I understand as amps go down in size, weight and price they might not be that strong into 4 ohms.  Most AVR's no longer even list power into 4 ohms and just a quick mention of 6 ohms.  I would presume that the TA-100 might have maybe 75 watts (or even 60-70) into 4 ohms at 0.10 to 0.25%THD and that would be fine performance in a low priced integrated amp.  Just because it is an integrated amp doesn't mean at least from Emo that is should have less than a high quality amp and if it is recommend for 4 ohm speakers then the specs should clearly indicate that.  Just because Joe Smith says it is fine with his 4 ohm speakers doesn't make it adequate for other 4 ohm speakers.  Some folks might buy it for other than the new Airmotiv speakers     

With the A-300 they do the same thing (ditto A-500 and A-700, with 2 ch and lower at all channels):

150 watts RMS per channel; 20 Hz - 20 kHz; THD < 0.1%; into 8 Ohms
300 watts RMS per channel; 1 kHz; THD < 1%; into 4 Ohms

Almost no amps really produce double power into 4 ohms over 8 ohms.  I'm guessing maybe the A-300 might produce 200-225 or more into 4 ohms with 0.1 or 0.2 % THD.   Why list 300 watts versus 150 watts when that is not under the same conditions.  

Where are the AP amp tests?  (Audio Precision)

I've been a huge Emo Fan Boy Old Fart for years now but I wish they wouldn't use clipping for power specs.   

[leonski]

Yes, it IS a bit of 'specsmanship' to rate it to double the 8 ohm power at 4 ohms. Too bad the distortion number doesn't really support that rating. So what? Maybe not 300 but perhaps 250 at a more reasonable level of distortion? Boy, that's a Huge Difference (not) and maybe 1db or so.
Used properly, you'll probably NEVER know. Medium or better speaker sensitivity. Low Reactance. Decent power handling. Proper size room = Not a CAVERN.

AP results? You already KNOW what you'll see. distortion dropping to some rollover point around 225watts or so, than rising. By 300 watts / 1% the distortion curve is going almost straight up. 10% might hit at 310 or 320 and that's IT.

To turn the question on its head, what is the 8OHM power at 1% distortion? 160 or 170, maybe?

[KeithL]

Enough already with the "let's put the specs under a microscope". routine...

With tube equipment, the distortion starts out pretty low at low power levels, then rises gradually until you get near clipping.
With push-pull tube equipment it's still usually a curved line, and still reasonably low overall (although a lot higher than with solid state equipment);
with SET tube equipment, it's sometimes more like a straight line - quarter distortion at a quarter power, half distortion at half power.
(The proper name for that is "a monotonic distortion curve".)

With virtually all modern solid state equipment, including ours, and including the BasX amps, the distortion starts out very low....
and it STAYS very low for most of the amplifier's power range, then rises quite suddenly as you get near clipping.
And this is what the distortion curves on the BAsX amps look like in general.

So, while a SET tube amp might be rated 1% THD @ 1 watt,  3% THD @ 3 watts, and 10% THD @ 10 watts....
A typical (similar) solid state amp would be 0.01% THD @ 1 watt, 0.02% THD @ 2 watts, 0.02% THD @ 9 watts, and 1 % THD at 10 watts....
(and probably 10% THD @ 11 watts if it's really a 10 watt amp).

Therefore (and I don't have the actual printouts in front of me here at home... just a hungry cat)......
The THD curve on the BasX amp is going to look pretty much like that.....
It stays very low over most of its power range, then rises suddenly just before clipping...
So, if you look at the rated power at 1% THD, you'll find that the amp delivers 90% or 95% of that power at 0.1% THD (or maybe 0.2% THD).
And the THD will probably be a LITTLE BIT higher overall into 4 ohms than into 8 ohms, which is also pretty normal.

I don't know the exact numbers, and I don't know why we decided to rate it at 1% on that particular one.
As you've probably noticed, we tend to vacillate between "rating things lower down the curve" and "rating them at 1% like most other people do".....

PLEASE try not to obsess over it.....

[KeithL]

I think I'd choose to "split the difference" on your final statement.

Tube amps tend to put out mostly second harmonic distortion, while most solid state amps tend to put out more higher harmonics.
The gererally accepted technical term would be that "lower order harmonics tend to dominate the distortion spectra of tube amps".
(It's actually due to a lot of factors common to tube and solid state designs... and not exactly just because they are one or the other.)

In any case, I think it's fair to say that MOST people agree that second harmonic distortion is less unpleasant sounding than higher harmonics.
And SOME people actually like the way second harmonic distortion sounds in moderate amounts.
(Personally, when it comes to distortion, I prefer "none"...)

The fact is that MOST tube amps put out enough second order harmonic distortion for it to be at least somewhat audible....
(And, yes, some put out a lot more than others.)
While most good quality solid state amps have low enough levels of distortion that it's usually inaudible to most people - except right up near clipping.

Sept 2, 2016 15:58:08 GMT -5 @tllfkacn said:

Sept 2, 2016 4:59:10 GMT -5 Boomzilla said:

The THD may be inconsequential; 1% is likely not audible. I'd agree that the BASX TA-100 might not be a BEST choice for 4-ohm loads, but I doubt that it's a bad choice. I have no idea what THD my Heathkit 12 watt tube amps put out, but it's probably more than 1% - and they sound glorious!

Boom

Tube amp distortion is traditionally not as audible as that from SS amps.  (Or maybe as gzubeck more correctly below says tube distortion is less noticeable/irritating the ear.)

[novisnick]

Sept 3, 2016 15:48:39 GMT -5 KeithL said:

Enough already with the "let's put the specs under a microscope". routine...

With tube equipment, the distortion starts out pretty low at low power levels, then rises gradually until you get near clipping.
With push-pull tube equipment it's still usually a curved line, and still reasonably low overall (although a lot higher than with solid state equipment);
with SET tube equipment, it's sometimes more like a straight line - quarter distortion at a quarter power, half distortion at half power.
(The proper name for that is "a monotonic distortion curve".)

With virtually all modern solid state equipment, including ours, and including the BasX amps, the distortion starts out very low....
and it STAYS very low for most of the amplifier's power range, then rises quite suddenly as you get near clipping.
And this is what the distortion curves on the BAsX amps look like in general.

So, while a SET tube amp might be rated 1% THD @ 1 watt,  3% THD @ 3 watts, and 10% THD @ 10 watts....
A typical (similar) solid state amp would be 0.01% THD @ 1 watt, 0.02% THD @ 2 watts, 0.02% THD @ 9 watts, and 1 % THD at 10 watts....
(and probably 10% THD @ 11 watts if it's really a 10 watt amp).

Therefore (and I don't have the actual printouts in front of me here at home... just a hungry cat)......
The THD curve on the BasX amp is going to look pretty much like that.....
It stays very low over most of its power range, then rises suddenly just before clipping...
So, if you look at the rated power at 1% THD, you'll find that the amp delivers 90% or 95% of that power at 0.1% THD (or maybe 0.2% THD).
And the THD will probably be a LITTLE BIT higher overall into 4 ohms than into 8 ohms, which is also pretty normal.

I don't know the exact numbers, and I don't know why we decided to rate it at 1% on that particular one.
As you've probably noticed, we tend to vacillate between "rating things lower down the curve" and "rating them at 1% like most other people do".....

PLEASE try not to obsess over it.....

One of your better posts IMHO. bravo, I think its well stated and to the point, sometimes you take a little longer to get there.

I do appreciate the detailed info of alot of your posts, God knows I need the education in this field, but this time I think you hit it just right.

To not obsess, for many, is very hard to do. 

Thanks  @keithl