Yes, it's a big one. The hole is 4cm in diameter. I'm not a fan of these small ferrite clips for you can't twist the cable around the "donut" multiple times, exposing it to the ferrite on a much larger scale. It's this one: https://www.arrow.com/en/products/b64290l40x830/epcos-tdk
I'm not even sure you would benefit from ferrite in this case, for its main purpose is to cancel out unwanted HF noise (>10khz). However, If you still want to try it out, please report if it improved the sound.
"the sound is excellent" is a sentence I said to myself about 28 times since I bought this amp in june. It was true every single time, right up until I thought "well, this is better". 😛
Since you live in Canada, I suppose you are having 120V AC, not 230V AC as we Europeans. The lower the AC voltage, the lower the possible noise.
@daniboun
I would avoid those ferrite clips to the speaker cables, both from inside and outside. What do you intent for them to do? If there is noise it's within the hearable spectrum (<20khz). But you would not want to get rid of any tones <20khz from the speaker cables, because that would mean getting rid of the sound partly too. If those ferrite clips do anything, they will harm/cut off your sound too. They cannot differentiate between good noise (music) and bad noise.
By plugging ferrite to the AC wires instead, you will cancel out the unwanted AC noise (<20khz) that will bleed into the speaker cables from inside, before it gets inside the amp circuitry or speaker cables, not after.
1. AC to PSU [we must choke/cut off here]
2. AC to DC [not much of a problem, both Meanwell and Mornsun are good EMI]
2. DC to Music [we must not choke/cut off]
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Sounds good ) clear explanation.
Something is sure : one of the Ferrite helps a lot... need to check which one )
When I remove the Ferrites Internally, my Cantus Ribbon tweeter is "hissing" a little bit @ max Volume pot. (-0DB)
Thanks for the feedback )
Interesting to read :
Use of Ferrites to stop RF
Several companies offer clamp-on and slide-on Ferrites. Some audio manufacturers claim that their Ferrites stop RF currents from being "picked-up" by power cords and other audio analog and digital cables. Ferrites are routinely used on computer internal and external cables to block RF. What is really happening here is that these are blocking radiated emissions from the computer so that the computer will pass FCC and foreign emission standards (CISPR, CSA). Their purpose is NOT to prevent RF from being "picked-up" by the signal wires. In some cases they have been added to internal computer cabling to attenuate radiation as a band-aid after the design is complete. These Ferrites will "round-off" the signal edges, removing much of the high-frequency content. The energy that Ferrites absorb is turned into heat as they are lossy elements.
Ferrites on Interconnects
What happens when you put one of these devices on your interconnect? It adds inductance to the cable causing it to be a low-pass filter (passes only lower frequencies). The problem is: if it is a large ferrite, or the composition is not correct, it can roll-off the high audio frequencies. Bad idea. Better to get a shielded cable if RF is suspected to be a problem. Some very small Ferrite beads, however, can be useful in taming some unshielded cables, such as the Kimber PBJ, but the ferrite should be installed on one conductor, not clamped across both.
Ferrites on Speaker Cables
What happens when Ferrites are installed on speaker cables? This is a more interesting question. Ferrites, with the right composition and size can be helpful for optimizing a speaker/cable/amplifier combination. I would avoid using the large clamp-on Ferrites used for EMI (Electro-Magnetic-Interference), since these generally add too much inductance. The Image Clarifier offered by Empirical Audio is a device that works for audio because the composition and size of the Ferrites is specifically chosen for audio cables. The Ferrite cores should be installed on one wire, not across both wires. The reason that Ferrites can improve the performance of speaker cables lies in their ability to add inductance and loss to the cable. We believe that this inductance reduces the natural resonances in a cable, which we believe can become audible through secondary effects. The ferrite creates a low-pass filter at very high frequency.
Something is sure : one of the Ferrite helps a lot... need to check which one )
When I remove the Ferrites Internally, my Cantus Ribbon tweeter is "hissing" a little bit @ max Volume pot. (-0DB)
Thanks for the feedback )
Interesting to read :
Use of Ferrites to stop RF
Several companies offer clamp-on and slide-on Ferrites. Some audio manufacturers claim that their Ferrites stop RF currents from being "picked-up" by power cords and other audio analog and digital cables. Ferrites are routinely used on computer internal and external cables to block RF. What is really happening here is that these are blocking radiated emissions from the computer so that the computer will pass FCC and foreign emission standards (CISPR, CSA). Their purpose is NOT to prevent RF from being "picked-up" by the signal wires. In some cases they have been added to internal computer cabling to attenuate radiation as a band-aid after the design is complete. These Ferrites will "round-off" the signal edges, removing much of the high-frequency content. The energy that Ferrites absorb is turned into heat as they are lossy elements.
Ferrites on Interconnects
What happens when you put one of these devices on your interconnect? It adds inductance to the cable causing it to be a low-pass filter (passes only lower frequencies). The problem is: if it is a large ferrite, or the composition is not correct, it can roll-off the high audio frequencies. Bad idea. Better to get a shielded cable if RF is suspected to be a problem. Some very small Ferrite beads, however, can be useful in taming some unshielded cables, such as the Kimber PBJ, but the ferrite should be installed on one conductor, not clamped across both.
Ferrites on Speaker Cables
What happens when Ferrites are installed on speaker cables? This is a more interesting question. Ferrites, with the right composition and size can be helpful for optimizing a speaker/cable/amplifier combination. I would avoid using the large clamp-on Ferrites used for EMI (Electro-Magnetic-Interference), since these generally add too much inductance. The Image Clarifier offered by Empirical Audio is a device that works for audio because the composition and size of the Ferrites is specifically chosen for audio cables. The Ferrite cores should be installed on one wire, not across both wires. The reason that Ferrites can improve the performance of speaker cables lies in their ability to add inductance and loss to the cable. We believe that this inductance reduces the natural resonances in a cable, which we believe can become audible through secondary effects. The ferrite creates a low-pass filter at very high frequency.
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Well I returned my A20a & bought an A10a instead. I'm using 8Ω speakers & the balanced output from my DAC is only impedance balanced anyway.
Alas the A10a is even worse than the A20a! It has a cyclic robotic noise on one channel & a really harsh buzz on the other. Again this was even when no input was connected, the amp/wiring was moved completely away from all other electrical devices, etc.
Maybe I've just been supremely unlucky, but the QC from Sabaj really doesn't seem up to scratch - I don't think I'm going to bother with anything else from Sabaj/SMSL/etc.
Alas the A10a is even worse than the A20a! It has a cyclic robotic noise on one channel & a really harsh buzz on the other. Again this was even when no input was connected, the amp/wiring was moved completely away from all other electrical devices, etc.
Maybe I've just been supremely unlucky, but the QC from Sabaj really doesn't seem up to scratch - I don't think I'm going to bother with anything else from Sabaj/SMSL/etc.
Try the Topping Pa3s, it's a double MA12070 and death silence (with RCA), check they measurements from Amirm at ASR forum.
For me the A20a is really excellent. I use it with balanced inputs, as already mentioned it's extremely quiet.
The maximum volume hissing problem with the RCA input is a bit disappointing, but I intend to correct this problem with the addition of ferrite and insulation of the HP cables which goes too close to the input OPs and NJW1194 preamp.
I'll give you a little report soon, I haven't got my listening tests.
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I also own this sabaj a20a ...
This is the best class d amp that I own, it puts the slap in all my TPA amps ...
The channel separation is huge thanks to its dual mono design!
But beware this amp has a huge gain (sensitivity), I personally use it at -20db.
Beyond the breath and noise may appear.
This amp is really alive! full of harmonics and details !!! it goes further than tpa 3255 ...
for the moment, I do not plan to modify it.
This is the best class d amp that I own, it puts the slap in all my TPA amps ...
The channel separation is huge thanks to its dual mono design!
But beware this amp has a huge gain (sensitivity), I personally use it at -20db.
Beyond the breath and noise may appear.
This amp is really alive! full of harmonics and details !!! it goes further than tpa 3255 ...
for the moment, I do not plan to modify it.
I own three of them and all three are quiet. It is true that the A20a has a ridiciculous high gain. I use them as poweramps at -20dB setting to match them with my sub-amp.
No, the gain is not very high compared to other amplifiers. Gain is 19,5db in lowmode and 25db in highmode. Sabaj uses power profile 2 which is supposedly in highmode. Therefore the gain is most likely 25db. It's probably the "fullness" of sound you notice, due to the capability of the Merus chips to reach down to 1.6ohm in PBTL in theory. There is no "ever so slightly backing off bass" when turning the volume up as there is with cheaper D-Class amps which have insufficient PSUs and where the (deepest) bass is getting thinner/pitched the louder you play.
Those three A20a you own are quite (to 100%?) by XLR or by RCA?
Those three A20a you own are quite (to 100%?) by XLR or by RCA?
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That the gain of the Merus chip itself. The A20a has a pre stage in it as well. Input sensitivity is specified as 150mV which for todays standards is very sensitive. A typical power amplifiers these days has an input sensitivity of around 1.5 to 2 Volts, a difference of at least 10dB. I did not measure the gain but in practice I have found it to be quite a lot more sensitive than my other amps.
I only use the XLR inputs.
I bought two of them new and one of them from a forum member. (actually paid more than new price for it) The second hand one has a slight hiss when volume is way up, the other two are dead quiet, maybe a newer version?
One of the issues I am contending with is sensitive speakers (91dB) in a nearfield desk environment. Cheap TPA3116 amps with factory set 32dB gain are completely unusable due to hiss, the A20a/A10a were better (if I ignored the high frequency whine in the A20a & the robotic noise in the A10a) but still far from 'silent'.
The only amp I've owned which I would call truly silent was a LM3886 build which had a very short signal path & silver/gold internal wiring.
The only amp I've owned which I would call truly silent was a LM3886 build which had a very short signal path & silver/gold internal wiring.
The Sabaj A20a is extremely quiet with the XLR input, as quiet as my class AB amplifiers. I also have the LM3886 LM1875, TDA7293 ... ETC ... they are all silent.
And I have speakers with AMT tweeter without resistance given the good efficiency of the Faital pro midrange and the Wavecor woofer
And I have speakers with AMT tweeter without resistance given the good efficiency of the Faital pro midrange and the Wavecor woofer
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Most FDA are completely silent. As long as inputs and sources are connected analog and input stages of amplifiers are analog it will be more noisy than necessary.
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I tried XLR, RCA & with no input connected - the hiss was the same. It was much better than any TPA3116 amp, but still not 'silent'.
I'm running one of the Sabaj amps on a B&C DE250 on a horn. This combo has a sensitivity of 106-108dB/1m and I don't hear any hissing or wining or other noise other than a very faint white noise, unnoticable from my listening position. I do have to mention that I'm running them from un-earthed outlets. In my country we don't have any mains earth in our living rooms. Maybe that's the difference?
Your amplifier is faulty because anyone they use it in xlr mode has NO hiss. Also read on the ASR forum.
Edit: @Sjef edit here in Canada we have mains earth.
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That is the opposite of the reality. In general houses built since the eighties have PE wall sockets for safety. With older houses it is up to the owner to update the electrical installation but this will change.
Since the sixties connection points are mounted in the ceilings/light points. This “centraaldozensysteem” has the PE wire more often than not running through it. Connecting an extra PE wire and pulling it through the PVC piping is an easy job too. In practice one can realise a PE socket in less than an hour. I have solved and helped to realise this quite a few times.
It is mandatory for safety AND for correct functioning of mains filters in devices with SMPS. Apparently it is a weak spot for many an audiophile and it often is neglected.
The Sabaj A20a does hiss at maximum volume. Please try it out carefully.
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In which case I guess I'm back to my point about the QC. I have tried two amps, both were no good at all, which is a pretty poor showing.
The Sabaj ONLY HISS to the maximum with the RCA input, it is dead silence with XLR.
Are you using the RCA input?
If so, as I already mentioned above, the Topping Pa3s has dead silence on the RCA input. I have a friend who just bought it.