Hello, I'm planning to replace the old amplifier/DAC pair and drive an old pair of high quality passive tower speakers plus a passive sub using a pair of FA123s (that's my budget).
Advantages: I can drive the amplifier stage directly in digital, vary the response curve and cross towers and subs with few phase problems. The towers are two MTMs with a pair of Vifa P17s in parallel each and a Morel tweeter, the sub is a single Peerless XXLS 10'' 830846 with 8+8 ohm dual voice coil.
The problem is that to align the sensitivities of the two 4 ohm MTM towers with that of the sub, I estimated that for the latter I need more than 4 times more power than that of each tower.
Solution A: I could bridge the two 125w stages of each FA123 and drive the sub with a total of 500w, using the 100w stage of each FA123 x each tower, which will continue to work with its passive crossover. However, I did not understand if this stage is qualitatively inferior to the 125 ones since its power does not change according to the impedance (100w@8 / 100w@4) as happens correctly for the other two (75w@8 / 125w@4 ). Will this stage have a lower current reserve and will therefore not be as good in transient response? That should be the best quality stage for me since I have to drive the towers at almost full range!
Solution B: I would have preferred for each FA123 to use one 125w stage for half sub and the other two for the single ways of the towers, piloting them as an active crossover and exploiting the full potential of this technology but unfortunately I fear that I would have to lower their level too much to align them with the low sensitivity of the sub.
In any case, I would still have a good infrastructure in hand to use for future new systems to be self-built such as WWMTM or WMTMW.
Following a scheme of two solutions:
Here are the questions:
1) ultimately what could be the best solution in your opinion, A or B, considering also that my extimations might be wrong?
2) how do the Hypex FA modules 'sound', in terms of audio quality?
3) which input digital formats are they able to deal with?
Any suggestion or personal experience will be welcome, thank you!
Advantages: I can drive the amplifier stage directly in digital, vary the response curve and cross towers and subs with few phase problems. The towers are two MTMs with a pair of Vifa P17s in parallel each and a Morel tweeter, the sub is a single Peerless XXLS 10'' 830846 with 8+8 ohm dual voice coil.
The problem is that to align the sensitivities of the two 4 ohm MTM towers with that of the sub, I estimated that for the latter I need more than 4 times more power than that of each tower.
Solution A: I could bridge the two 125w stages of each FA123 and drive the sub with a total of 500w, using the 100w stage of each FA123 x each tower, which will continue to work with its passive crossover. However, I did not understand if this stage is qualitatively inferior to the 125 ones since its power does not change according to the impedance (100w@8 / 100w@4) as happens correctly for the other two (75w@8 / 125w@4 ). Will this stage have a lower current reserve and will therefore not be as good in transient response? That should be the best quality stage for me since I have to drive the towers at almost full range!
Solution B: I would have preferred for each FA123 to use one 125w stage for half sub and the other two for the single ways of the towers, piloting them as an active crossover and exploiting the full potential of this technology but unfortunately I fear that I would have to lower their level too much to align them with the low sensitivity of the sub.
In any case, I would still have a good infrastructure in hand to use for future new systems to be self-built such as WWMTM or WMTMW.
Following a scheme of two solutions:
Here are the questions:
1) ultimately what could be the best solution in your opinion, A or B, considering also that my extimations might be wrong?
2) how do the Hypex FA modules 'sound', in terms of audio quality?
3) which input digital formats are they able to deal with?
Any suggestion or personal experience will be welcome, thank you!
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A pair of FA122s were the worst sounding amplifiers that I've heard on my K-402/KPT-KHJ-LF Jubilees (using TAD TD-4002 compression drivers). It was so bad that I have a difficult time describing just what was wrong. They were like the worst sounding 300B SETs with severely undersized output transformers--only worse.
Chris
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Argh, what a bad news... Sincerely It's really difficult for me to believe that in few cmq of space there's THE SOLUTION for the future of high-end reproduction, but all is possibile in this world.
Please tell me, what amplifier gave you the best results with your jewels, and overall, what kind of cross-over, have you got original Jubilee?
Please tell me, what amplifier gave you the best results with your jewels, and overall, what kind of cross-over, have you got original Jubilee?
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Hmm, I would look up other users opinions also. I have no experience with these modules. But when it comes to amplifiers, these kind of extreme judgements make me itch!
1)
Solution A - not recommended at all. The NC100HF module in the FA123 is simply unable to drive anything else than high-impedance tweeters.
Solution B should work very well I think.
2) They sound like nothing - very transparent in my opinion.
3) Digital inputs must be PCM, and can be any bit depth and rate supported by SP/DIF and/or AES/EBU.
Solution A - not recommended at all. The NC100HF module in the FA123 is simply unable to drive anything else than high-impedance tweeters.
Solution B should work very well I think.
2) They sound like nothing - very transparent in my opinion.
3) Digital inputs must be PCM, and can be any bit depth and rate supported by SP/DIF and/or AES/EBU.
I would recommend a First Watt amplifier for the high frequency driver(s)--like my now-discontinued F3. Other owners of the same drivers/horns now use push-pull tube amplifiers (not really SETs), although some still cling to their SETs and turntables that drag a rock through plastic. The bass bin amplifier can be much less expensive. I use older class AB Crown D75As for the other channels in my 5.2 array--since they were generally available for ~$100 USD used on ebay a few years ago. Their slew rate is regulated down a bit for stability. There is at least one guy that removed the slew rate restrictions via a hardware modification (the proprietor of the old Juicy Music tube preamps and amplifiers--that he called "the Duke"). I found that for the bass bins, the speed up of slew rate wasn't audible.
I've found that the Xilica XP or XD series DSP crossovers work extremely well (a brand name first proposed by Tom Danley). The Xilica Solaro series is apparently the heir apparent for the future but the prices seem to be significantly higher. I still recommend XP and XD series for price/performance.
If using lower sensitivity drivers/horns, it is possible to use miniDSP 2x4 HD or similar but be careful about quiescent noise levels in anything but the 2x4 HDs (assuming high sensitivity designs). ElectroVoice DC-One is good but not quite as hi-fi as Xilica (in my opinion): 48 kHz vs. 96 kHz sampling rate for the Xilica and miniDSP 2x4 HD. This seems to correlate to higher sound quality in my subjective experience.
I too really wanted the Hypex FusionAmps to work. I was dumbfounded when I heard the result.
Chris
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I do have the original Jubilees with TAD TD-4002 drivers replacing the old K-69-A drivers. I use tapped horn subwoofers below 40 Hz. These DIY subs based on the TH-SPUD design are located just behind each Jubilee are on the front wall, thus breaking the bass/infrasonic bass band into two ways to limit AM and FM distortion. Bass THD levels and group delay are low, as shown below:
Chris
Chris
The question might be if you want clean power or not. The nCore amps have virtually no distortion, especially compared to amps like the mentioned Firstwatt F3, which has around 1% THD at 1 W, compared to 0.0015% on the nCore.
The reason why I replied to your question should be apparent. Whatever arguments to the contrary should be countered by actual listening trials--not harmonic distortion measurements, which in my experience are not very good indicators of amplifier subjective sound quality.
However, for those that continue to cling to THD figures of merit for amplifiers, they may find solace in their decision to buy the FusionAmps for their active bi/tri-amping DIY projects. In those cases, I wish you all the best of luck in those endeavors...
Chris
However, for those that continue to cling to THD figures of merit for amplifiers, they may find solace in their decision to buy the FusionAmps for their active bi/tri-amping DIY projects. In those cases, I wish you all the best of luck in those endeavors...
Chris
That has not been my experience. Respectfully, we all hear things differently, and I do not dispute your perception of the Hypex amps.
I have used both the FA253 and FA123 in active speaker projects. I found them to be some of the most neutral and transparent amps I have ever heard.
20 years ago I would have been very biased against Class D amps... small power supplies, tiny semiconductor gain stages... Where is the big massive linear power supply, beer-can-sized filter caps, the big MOSFETs mounted on a huge extruded aluminum heatsink? But now I listen with an open mind, and I am really impressed with nCore class D amps.
Milliwatts vs. watts is probably the root of the difference of opinions. I don't think it's too much of a stretch to mention that I can hear perhaps things (very clearly) that others are unable to hear because of the difference in efficiencies alone.
But note: the sound quality of the first watt of output power by any amplifier is, in my experience, one of the best indicators of its inherent design and implementation quality. A TAD TD-4002 driver on a K-402 horn has a minimum of 105 dB/watt efficiency across its operating band. Direct radiating drivers with 85 dB/w efficiency are running at ~1% of that efficiency. It's been my experience that that direct radiating drivers being operated at that low level of efficiency suffer in terms of sound quality when playing acoustically recorded music without added recording compression, even when listening at 10 feet/3 m listening distance in a home-sized room (i.e., music crest factors above 10-12 dB) at or even well below non-amplified acoustic performance levels. If you're okay with that limitation, then by all means...
Chris
But note: the sound quality of the first watt of output power by any amplifier is, in my experience, one of the best indicators of its inherent design and implementation quality. A TAD TD-4002 driver on a K-402 horn has a minimum of 105 dB/watt efficiency across its operating band. Direct radiating drivers with 85 dB/w efficiency are running at ~1% of that efficiency. It's been my experience that that direct radiating drivers being operated at that low level of efficiency suffer in terms of sound quality when playing acoustically recorded music without added recording compression, even when listening at 10 feet/3 m listening distance in a home-sized room (i.e., music crest factors above 10-12 dB) at or even well below non-amplified acoustic performance levels. If you're okay with that limitation, then by all means...
Chris
By the way, @hifijim, there was a reason why I wrote the sentence that I did (shown above).
It isn't very nice to quote out of context, especially less than one-sentence quotes.
Chris
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Excuse me Chris, I'm not sure I understand the correlation between low efficiency systems and the low quality of the first watt of an amplifier: given particular recordings, does a low efficiency system or a high efficiency one suffer more with, let's say, low microwatt quality amplifier (which could explain your negative experience with FA122)?
Just the opposite: if your loudspeakers take much lower power to produce a realistic SPL, you can clearly hear what's happening below the levels of someone using much lower efficiency drivers/loudspeakers cannot. (One must also keep in mind that the bass bin is almost always the lowest efficiency portion of any loudspeaker design.)
If you can't hear very well what's really being output at lower SPL, you might begin to think that other issues exist in your listening environment, such as your own hearing or perhaps room acoustics or source music quality. You might tend to accommodate to those issues, but perhaps remain dissatisfied with the low level sound quality (which is a commonly heard compliant of those listening to lower efficiency loudspeakers that report that they must use more power to "wake up" the loudspeakers).
Chris
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The OP MTM speaker is far from high efficiency speakers, so this "discussion" and the example of Cask05 is out of context