HiFiMan Susvara
Jul 15, 2020 at 9:31 PM Post #4,186 of 11,479

bagwell359

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I hook mine up directly to my car battery, it really lifts the veil.

Have to clean up all corrosion on the batteries - with pure O2 at 15 psi and San Pellegrino (Saratoga in a pinch)....sorry, silly night
 
Jul 15, 2020 at 9:37 PM Post #4,187 of 11,479

llamaluv

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I hook mine up directly to my car battery, it really lifts the veil.

Or allow one to see "beyond the veil", most likely.

As might listening to any pair of headphones connected to 780 watt monoblocks, after forgetting to turn down the volume.
 
Jul 16, 2020 at 4:14 AM Post #4,188 of 11,479
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It performs better than DACs costing $40k that I've heard...hardly overpriced from that point of view. :)

Agreed, it's always a matter of perspective. A 10k DAC capable of besting a product five times as costly would be at the opposite end of overpriced :L3000:
 
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Jul 19, 2020 at 5:50 PM Post #4,189 of 11,479

tonereef

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Further to my post of June 18 (p.263), Soo In Chae ran some tests on a QA401 analyzer on Bakoon 13-R relating to Susvara and provided me with info as well as graphs (if anyone is interested in the latter please PM me). Here's a data summary (all tests at 60 ohms resistance), followed by some of his comments.

At 20dB gain, THD is 0.1% (-60dB) at 2.8w. This rises to about 0.5% THD at 4.1w (beyond which distortion rises very steeply). The graph shows that the lowest THD, around -91 to -95dB, is below 100mw. (Soo In says that under 1w, THD remains below 0.03%.)

At 16.4dB gain the power vs. THD graph is almost identical up to 2.8w (where it ends).

Another graph with the same settings (16.4dB gain, 0.1% THD + noise, 2.8w) shows some interesting things. Inputting a 1K signal at 5.9 dBV and a 20K signal at -14.1dBV, SNR is measured at 102dB, But if the input signal is assigned 0dBV on the graph there are what look like significant harmonic spikes - -45dBV at 2K, -40dBV at 3K, -55dBV at 4K, -65dBV at 5K, then dropping to near 80 or below for the 6th harmonic and higher until by 12K there are no spikes above the noise (which is below -110dBV). I would assume that the harmonic distortion would be lower when the amp is being pushed less.

(Macedonian Hero, how to these measurements compare with other Bakoon amps, do you know?)

Here are some of Soo In Chae's comments:

While I don’t have Susvara, I know two local customers run the AMP-13R for their Susvara. They both use 2.3V standard output DAC (Rockna Wavelight, Matrix Audio Element X), and one tells me that he generally listens around at gain step 20 on the AMP-13R (out of gain step 50) and the other one at around the step 35. This is about -2.5 dB and 10.7 dB respectively on the AMP-13R. While everyone’s different, they don’t run the AMP-13R with preamps and the AMP-13R’s max gain of 22.5 dB seems to be just fine. The AMP-13R is actually a variable gain amplifier as the attenuator is located at the output stage controlling the amplification factor (unlike the conventional preamps/amps where the volume pot is located at the input). This results the SNR almost constant from gain step 1 to gain step 50 as the noise gets lower when the input signal gets low. I believe this is a part of reasons why people who enjoy low level listening (and headphones) love our amplifiers. The AMP-13R's gain step ranges from 0 to 50. At step 50, it is +22.5 dB, and at step 1, it is - 37 dB.

The noise can be also measured by the analyzer and I did them at +0 dB and max gain 22.5 dB. They are quite low at 64.6 uV and 176 uV (RMS L on the graphs).

As for the harmonics, I think we are already listening to some amounts of distortions on amplifiers, headphones, speakers, etc combined, and there are some different theories whether 2nd order or 3rd order is preferred. In the end, I believe the listening evaluation is important.


I still think that with a maximum usable gain of around 20dB Bakoon would not always play loud enough for my tastes coming direct out of my SACD player. I don't think it would be close to realistic levels for rock, for example.
 
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Jul 19, 2020 at 6:29 PM Post #4,190 of 11,479

jlbrach

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I cannot speak to the bakoon 13r with speakers but with susvara it is marvelous...drives them with authority ...great control and detail..marvelous combo..better than I have heard the susvara with any other HP thus far FWIIW...I had gotten rave reviews from a buddy whose opinion I respect and I concur
 
Jul 21, 2020 at 1:05 AM Post #4,191 of 11,479

koven

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Debating if it's worth picking up an adapter box to try this w/ Susvara.. on one hand I'm curious, on the other hand it's probably overkill and will serve my speakers better. Perhaps not worth the hassle? Or maybe it is.. :thinking:

_DSC7754.jpg
 
Jul 21, 2020 at 1:27 AM Post #4,192 of 11,479

AnaKinDV8

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Debating if it's worth picking up an adapter box to try this w/ Susvara.. on one hand I'm curious, on the other hand it's probably overkill and will serve my speakers better. Perhaps not worth the hassle? Or maybe it is.. :thinking:

Misread the post, it seems the question is about the adapter box and not the amp. Also wondering if direct connection is possible as the adapter just gets in the way.
 
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Jul 21, 2020 at 1:31 AM Post #4,193 of 11,479

koven

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I say it's worth it, get it. :smiling_imp: The only question is the speaker adapter box, if that's really necessary or it just gets in the way.

I know some have said resistor box degrades sound but I've also read that only SS amps can be connected direct, whereas tube taps are not safe direct and may damage the amp. I don't know for sure as I've never tried either, but it seems too risky w/o the box.

@dleblanc343 said he uses direct on his MC225 so I'm assuming maybe it's fine, but then again this would be 75W/ch vs 25 if that makes a difference.

Seems safer to just take a potential SQ hit w/ the box rather than risk damage. Then again if I'm taking an SQ hit w/ the box, is it even worth trying? The more I think about it, the more I'm leaning towards just leaving it alone in my 2-ch.
 
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Jul 21, 2020 at 1:48 AM Post #4,194 of 11,479

Focux

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Debating if it's worth picking up an adapter box to try this w/ Susvara.. on one hand I'm curious, on the other hand it's probably overkill and will serve my speakers better. Perhaps not worth the hassle? Or maybe it is.. :thinking:


Is it me or the way u took this photo that makes the tubes look like something from Arkham City’s Ace Chemicals :p
 
Jul 21, 2020 at 10:49 AM Post #4,197 of 11,479

Articnoise

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I know some have said resistor box degrades sound but I've also read that only SS amps can be connected direct, whereas tube taps are not safe direct and may damage the amp. I don't know for sure as I've never tried either, but it seems too risky w/o the box.

@dleblanc343 said he uses direct on his MC225 so I'm assuming maybe it's fine, but then again this would be 75W/ch vs 25 if that makes a difference.

Seems safer to just take a potential SQ hit w/ the box rather than risk damage. Then again if I'm taking an SQ hit w/ the box, is it even worth trying? The more I think about it, the more I'm leaning towards just leaving it alone in my 2-ch.

“If you have an amplifier with power tubes in the output section, then you cannot operate it without speaker load connected.

Simply put, in the tube amp output section, the transformer performs the task of transforming the speaker load to a load the tubes want to see. For example, on an amp with four EL34 output tubes the transformer makes an 8 ohm load look like a 1200 ohm load for the tubes.

This is also why you should not mismatch your load to the impedance indicated or selected on the amp. If you are on the 4 ohm tap of the transformer it transforms the same 1200 ohm to the tubes. Tubes are happy. If you are on the 8 ohm tab with a 4 ohm load, the same transformer will put a 600 ohm load on the tubes and they will not perform correctly.

Now, if you do not connect a load, the transformer cannot reflect a load and the tubes will only see the wire in the transformer and a big coil as a load. This is basically shorting the tubes to the high voltage and it will cause damage to the amplifier eventually. Another way to think of it is the power tubes pull on the transformer which magnetizes the output transformer; this in turn creates a voltage on the output of the transformer to drive the speaker load. If there is no load, all that energy has nowhere to go, so instead it will be fed back to the power tubes causing damage. Usually the tubes will go into a growing oscillation that eventually burns them. Most of the time the output transformer is ok, but if left on long enough it can also be damaged. And playing through an unloaded tube amp will only speed up the road to damaging the amp.”


https://carvinaudio.com/blogs/guita...akers-connected-here-s-when-you-can-and-can-t

Most solid state amps are voltage sources which means they will output a given voltage and the current is determined by the load. A short circuit will cause the amp to *try* to supply very high currents with typically disastrous results (if there are no protection measures). A tube is the opposite. It's a current source and will produce a given current level with the voltage be determined by the load. A short circuit is no problem because the voltage required to maintain a give current is very low into a short. But an open circuit is a real problem. The tube is trying to drive a set current through an air gap and will raise the voltage to the physical limits of the tube in the attempt...with typically disastrous results. There are ifs ands ors and buts but that is the gist of it.

My thought: this is true for some tube amps and not for all, but I think that it’s always best to let a tube amp “see“ a load, so never disconnect the speakers or HP from a turned on tube amp.

PS. Some folks have ditched the resistor box and instead put the resistor directly on the speaker taps.
 
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Jul 21, 2020 at 12:06 PM Post #4,199 of 11,479

SteveM324

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Debating if it's worth picking up an adapter box to try this w/ Susvara.. on one hand I'm curious, on the other hand it's probably overkill and will serve my speakers better. Perhaps not worth the hassle? Or maybe it is.. :thinking:

_DSC7754.jpg
I had that amp in my speaker system for several years to drive Harbeth SLH 5+ speakers. It did quite well and I liked it. I only sold it because I upgraded my speakers to the much bigger Harbeth M40.1 and I wanted a lot more power in my big room. I‘m using a McIntosh MC452 to drive my 40.1 speakers. You could call McIntosh to ask them your question. They always have technical support for questions.
 
Jul 21, 2020 at 12:30 PM Post #4,200 of 11,479

koven

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I had that amp in my speaker system for several years to drive Harbeth SLH 5+ speakers. It did quite well and I liked it. I only sold it because I upgraded my speakers to the much bigger Harbeth M40.1 and I wanted a lot more power in my big room. I‘m using a McIntosh MC452 to drive my 40.1 speakers. You could call McIntosh to ask them your question. They always have technical support for questions.

Must sound great w/ the Harbeth. I'm looking to pair mine w/ Focal Sopra 1 but waiting for a deal to pop up. Have the Dynaudio S40 and ProAc 1SC in the meantime. I'm guessing you never bothered trying to hook up headphones to it. I don't know if I will after reading what @Articnoise posted, I'd probably do something dumb like leave the amp on w/ Susvara unplugged.
 

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