a 2nd SP400 as Preamp to power the SUSVARA

[Red@]

Hello guys,
I bought an SMSL SP400 as a headphone Amp for my Susvara, but I quickly realized that it does not have enough gain to power it at its full potential; at high gain and 99 volume I still try to trun the nob for more.
I'm now thinking of buying a second SP400 to add as a Preamplifier in the chain in order to raise the input voltage/current and hopefully double the gain output to 22 db.

Any advice guys ?

NB: As I EQ my susvara by adding a bass shelf, I already lose a 5 db input from the source.

 

[faheem]

Using balanced, your Susvara will be able get to over 115dB SPL , pre eq.

 

[Red@]

Using balanced, your Susvara will be able get to over 115dB SPL , pre eq.

Do you have the set up and tried it ?
Because I have, and it is no where near that number. I would not have commented otherwise..

 

[charleski]

How is the amp hooked up? The numbers certainly indicate that it should be hitting peaks of 115dB, but that’s on a 4V balanced input.

 

[Red@]

How is the amp hooked up? The numbers certainly indicate that it should be hitting peaks of 115dB, but that’s on a 4V balanced input.

It is hooked up to an x26 pro (vivid filter) via XLR, so 5.2v input into the amp.
If you go to the sp400 threads, I am not the only one having those power deficiencies. i contacted smsl and they acknowledge that the gain is not enough for the susvara.
That is why I would like to add some power to the chain

 

[faheem]

Do you have the set up and tried it ?
Because I have, and it is no where near that number. I would not have commented otherwise..

No, I don't have the SP400, I am basing that off the measured performance done by amir. If you have a multimeter and 56 Ohm resistor, you can measure your voltage output.

I have a Susvara which I use with a Diablo and once in awhile an A90. I personally hardly ever go above the lowest gain on either, for comfortable listening. If I'm in the mood to crank them up, I can handle 10V for a track.

 

[faheem]

It is hooked up to an x26 pro (vivid filter) via XLR, so 5.2v input into the amp.
If you go to the sp400 threads, I am not the only one having those power deficiencies. i contacted smsl and they acknowledge that the gain is not enough for the susvara.
That is why I would like to add some power to the chain

Measure your output, to see what's going on.

 

[charleski]

The problem with just increasing the input voltage is that you’ll probably just overload the input stage. It’s worth checking that you are actually getting voltage outputs that match the measurements so you know there isn’t a fault. At full power balanced in/out it should generate ~15Vrms across a 56ohm resistor on a 0dbFS sine wave. You’d have to rig up a test cable to measure this, but that’s fairly easy.

 

[charleski]

One other thing to check is that there isn't anything else in your digital chain that reduces the output from your DAC. Volume Leveling/ReplayGain will typically reduce the output by 14dB (or even more if it follows the EBU or SMPTE standards).

 

[TonyNL]

I assume you already own the SP400 before buying the Susvara, otherwise it doesn't make sense. Susvara is really really power hungry. There were sound coming out from my RME ADI-2 DAC fs and AAA789, but you can tell it's not going well. There is no depth, "power" or soundstage. It's just dead. If you have a speaker amp. I encourage you to buy the HE-1 adaptor and give it a try. If you are planning to upgrade the whole chain, because of the Susvara. There is a special version coming from Holo May DAC, but with powering the Susvara in mind, so you won't need a speaker amp. You posted this some time ago, how is it going now?

 

[Red@]

I assume you already own the SP400 before buying the Susvara, otherwise it doesn't make sense. Susvara is really really power hungry. There were sound coming out from my RME ADI-2 DAC fs and AAA789, but you can tell it's not going well. There is no depth, "power" or soundstage. It's just dead. If you have a speaker amp. I encourage you to buy the HE-1 adaptor and give it a try. If you are planning to upgrade the whole chain, because of the Susvara. There is a special version coming from Holo May DAC, but with powering the Susvara in mind, so you won't need a speaker amp. You posted this some time ago, how is it going now?

Hi, thank you for you response.
As far as the chain goes, the amp is the only weak element that I would like to improve (the DAC is otherwise top notch).
And I did make the mistake of purchasing tue sp400 specifically for tye Susvara, not inowing that it does not deliver enough current, as well as having limited gain for such inefficient headphones (especially including the -5db due to eq).
Since I the DAC seems to be very good a delivering transient and being transparent. I am waiting for an amp that can do both.
The Cayiin IHA-6 is for example has high current delivery but poor transparency. The topping stuff has very weak transients.
Hopefully something that checks all those boxes comes along.
Too bad there is not a @gustard Amp designed for inefficient planars. I like their products (minus the swappable Opamps stuff, that is PR stunt).

 

[raif71]

Would the Pre90 make sense in the chain? X26->Pre90->SP400, will this provide enough power for the susvara?

 

[Red@]

Would the Pre90 make sense in the chain? X26->Pre90->SP400, will this provide enough power for the susvara?

I don't like topping Amplifiers they make audible compromises in terms of transient and dynamics when used in certain chain. Their input stage can be saturated with certain DACs and their output stage may not be enough for certain chains.
And it doesn't solve my current delivery issue with the sp400.
The flux VOLOT seems to be a real beast in terms of current delivery and output stage. I am waiting for a Amir or somebody to test it in order to verify the other metrics. I also am waiting for a @gustard competitive product.

 

[trl]

Based on https://headphonetestlab.co.uk/test-results-manufacturers-e-h-hifiman-susvara your cans should have a sensitivity of about 79.2dB/mW or 91.5dB/1V and 59.3 Ohms impedance @ 6.14kHz.

Based on http://www.digizoid.com/power.php this is the power needed by an amp to correctly drive these cans:
Listening Loudness Voltage Needed Current Needed Power Needed
Safe 85 dB SPL 0.48 Vrms8 mA 3.84 mW
Moderate 100 dB SPL2.69 Vrms 44.83 mA 120.6 mW
Fairly Loud 110 dB SPL8.5 Vrms 141.67 mA 1204.17 mW
Very Loud 115 dB SPL15.11 Vrms 251.83 mA 3805.2 mW
Painful 120 dB SPL26.86 Vrms 447.67 mA 12024.33 mW

Per https://www.smsl-audio.com/upload/portal/undefined/SP400Manual.pdf this amp has a gain of 11.6 dB which means 3.8X (check http://www.sengpielaudio.com/calculator-gainloss.htm too).

Per https://www.audiosciencereview.com/forum/index.php?threads/smsl-sp400-review-headphone-amp.19346/ this amp has enough power to drive these cans, so almost 14.5 V RMS means 3.54 Watts in balanced operation, so peaks to about about 114 db SPL (definitely over 90dB average SPL).

As other stated here, at least from the papers and tests, SP400 should drive them properly, but only if you feed it with -1...0 dB input tracks. In case you're using an EQ or DSP that lower the input volume with 3 dB or more then you'll need an amp with a higher gain, indeed.

Now you might want to measure the actual gain of your amp (Vout/Vin) and then max Vout of your DAC, in balanced operation, then update the thread with news.

 

[trl]

The flux VOLOT seems to be a real beast in terms of current delivery and output stage.

About the same power of 2 x 16W is also delivered by the Burson 3CX or Soloist 3X, which might be easier to find and maybe a beat cheaper too.

 

[Red@]

Based on https://headphonetestlab.co.uk/test-results-manufacturers-e-h-hifiman-susvara your cans should have a sensitivity of about 79.2dB/mW or 91.5dB/1V and 59.3 Ohms impedance @ 6.14kHz.

Based on http://www.digizoid.com/power.php this is the power needed by an amp to correctly drive these cans:
Listening Loudness Voltage Needed Current Needed Power Needed
Safe 85 dB SPL 0.48 Vrms8 mA 3.84 mW
Moderate 100 dB SPL2.69 Vrms 44.83 mA 120.6 mW
Fairly Loud 110 dB SPL8.5 Vrms 141.67 mA 1204.17 mW
Very Loud 115 dB SPL15.11 Vrms 251.83 mA 3805.2 mW
Painful 120 dB SPL26.86 Vrms 447.67 mA 12024.33 mW

Per https://www.smsl-audio.com/upload/portal/undefined/SP400Manual.pdf this amp has a gain of 11.6 dB which means 3.8X (check http://www.sengpielaudio.com/calculator-gainloss.htm too).

Per https://www.audiosciencereview.com/forum/index.php?threads/smsl-sp400-review-headphone-amp.19346/ this amp has enough power to drive these cans, so almost 14.5 V RMS means 3.54 Watts in balanced operation, so peaks to about about 114 db SPL (definitely over 90dB average SPL).

As other stated here, at least from the papers and tests, SP400 should drive them properly, but only if you feed it with -1...0 dB input tracks. In case you're using an EQ or DSP that lower the input volume with 3 dB or more then you'll need an amp with a higher gain, indeed.

Now you might want to measure the actual gain of your amp (Vout/Vin) and then max Vout of your DAC, in balanced operation, then update the thread with news.

I already discussed this in another thread.
But I will tell it again.
I use a DAC with 5.1V output. And I use the SP400 in max volume (99). And I don't use any eq in the source (so that the -5db is not a parameter here). And I still not nearly close to the uncomfortable listening zone. You can also look at the sp400 thread, you will see people (who have Susvara) with similar experience to mine.
Also the customer support from smsl confirmed to me that it is not enough for the susvara.
So the experience sometimes differ from the theorie, when the theorie dosen't account for all factors. And I repeat, ther is a circulating belief among experts that current delivery is essential for inefficient planars. Just as is high voltage for high impedance headphones.
The amp also sound muted, in terms of dynamics, probably due to it's limited output stage in this specific chain configuration

 

[Red@]

About the same power of 2 x 16W is also delivered by the Burson 3CX or Soloist 3X, which might be easier to find and maybe a beat cheaper too.

The quality control is not great, as I read in multiple forums that people got their headphones destroyed and replaced, due to the 3X instabilities.

 

[trl]

I've read your comments, but I've seen zero measurements. Maybe your SP400 has a lower gain than 3.8X or your DAC has a lower output voltage. Also, maybe your Susvarna has a lower sensitivity, so you need to figure out which component is different then the specs and get back here to us to inform us as well.

 

[Red@]

I've read your comments, but I've seen zero measurements. Maybe your SP400 has a lower gain than 3.8X or your DAC has a lower output voltage. Also, maybe your Susvarna has a lower sensitivity, so you need to figure out which component is different then the specs and get back here to us to inform us as well.

As I said several other people have a similar case.
I am not a reviewer but a simple customer sharing his experience like those other people before me. When I find an amp that imoroves my situation, I will share that.
If you are interested in that specific test I urge you to buy this chain and show me how I am mistaken, as I surely don't posess you knowledge.

 

[TonyNL]

Based on https://headphonetestlab.co.uk/test-results-manufacturers-e-h-hifiman-susvara your cans should have a sensitivity of about 79.2dB/mW or 91.5dB/1V and 59.3 Ohms impedance @ 6.14kHz.

Based on http://www.digizoid.com/power.php this is the power needed by an amp to correctly drive these cans:
Listening Loudness Voltage Needed Current Needed Power Needed
Safe 85 dB SPL 0.48 Vrms8 mA 3.84 mW
Moderate 100 dB SPL2.69 Vrms 44.83 mA 120.6 mW
Fairly Loud 110 dB SPL8.5 Vrms 141.67 mA 1204.17 mW
Very Loud 115 dB SPL15.11 Vrms 251.83 mA 3805.2 mW
Painful 120 dB SPL26.86 Vrms 447.67 mA 12024.33 mW

Per https://www.smsl-audio.com/upload/portal/undefined/SP400Manual.pdf this amp has a gain of 11.6 dB which means 3.8X (check http://www.sengpielaudio.com/calculator-gainloss.htm too).

Per https://www.audiosciencereview.com/forum/index.php?threads/smsl-sp400-review-headphone-amp.19346/ this amp has enough power to drive these cans, so almost 14.5 V RMS means 3.54 Watts in balanced operation, so peaks to about about 114 db SPL (definitely over 90dB average SPL).

As other stated here, at least from the papers and tests, SP400 should drive them properly, but only if you feed it with -1...0 dB input tracks. In case you're using an EQ or DSP that lower the input volume with 3 dB or more then you'll need an amp with a higher gain, indeed.

Now you might want to measure the actual gain of your amp (Vout/Vin) and then max Vout of your DAC, in balanced operation, then update the thread with news.

Yes, I know that talk. So I didn't bought an amp, coz I thought an AAA789 with 6watt should do, but having sound doesn't mean the sound has quality. After 8 weeks switching between my RME ADI2 dac and AAA789. I know it's a waste. So I upgraded my amp.