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JL ELectronics Sylph-D200 Amplifier Module Review

enio nery

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Philippines Represent! I have been eyeing this particular board for some time now. but i have no time for DIY anymore.
 

miofu

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Hi all

I have question regards this gain - power - sinad topic.
After review here I've bought Behringer A800.
I'm using it with desktop monitors and usb sound card with analog volume control via balanced connection and I'm very happy with it. I don't need all that power and as at max positions of Behringer's controls I can hear hiss in quiet conditions through tweeters I've reduced gain to 10 o'clock. I adjust volume using sound card pot and it still can be more loud than enough, and hiss has gone.
Is it true that by reducing gain on Behringer(or every other amp) but losing max power, I also increased SINAD and other parameters?
Is is now similar situation like here with lower max gain amp like Sylph-D200? So lower amp gain need to be compensated by higher source voltage?
 

abdo123

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Hi all

I have question regards this gain - power - sinad topic.
After review here I've bought Behringer A800.
I'm using it with desktop monitors and usb sound card with analog volume control via balanced connection and I'm very happy with it. I don't need all that power and as at max positions of Behringer's controls I can hear hiss in quiet conditions through tweeters I've reduced gain to 10 o'clock. I adjust volume using sound card pot and it still can be more loud than enough, and hiss has gone.
Is it true that by reducing gain on Behringer(or every other amp) but losing max power, I also increased SINAD and other parameters?
Is is now similar situation like here with lower max gain amp like Sylph-D200? So lower amp gain need to be compensated by higher source voltage?

yes that is the expected results, as long as the DAC can still push the speaker to the desired volumes (at the low gain settings) then lower gain will reduce noise (by increasing the signal to noise ratio of the DAC).
 
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miofu

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yes that is the expected results, as long as the DAC can still push the speaker to the desired volumes (at the low gain settings) then lower gain will reduce noise.
thx for confirmation ;)
DAC is emu 0404 usb, I don't hear any distortion. Interface spec says +12dBV max for balanced output.
 

HammerSandwich

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For me it's ok as long as it's within range of most DAC's output.
It's good to have options. As an easy example, the MOTU Ultralite which ASR recently reviewed gives best performance at ~7.5Vrms (+11dB versus 2Vrms). Best gain with a 100W amp would be ~12dB. A typical amp with 29dB gain must make >5kW to avoid clipping. Far from ideal.

Let's note that many headphone amps include gain switches. The noise difference is more obvious than with speakers, but users notice. And they appreciate simply flipping a switch for better whole-system performance. Why not with speaker amps, too?
 

respice finem

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300W is at higher distortion. You can easily have 200W per channel <1%.
But hardly with this cooling... Just a few loose thoughts:
Not being a fan of fans and their noise, the thing that bothers me a bit about many "chip amps" from several manufacturers, are the "miniature" radiators. A decent size radiator would eliminate the need for a fan, and provide lower operating temperatures, prolonging the life of the chip(s), wouldn't it? Having a small enclosure is fine, but it's not really difficult to place a radiator on the side, or top of an enclosure, with free airflow, so much better than inside the box. May need a heatpipe in some cases. I would pay the extra "20$".
An example of the principle i'm referring to, no amp, a PC, but just to demonstrate the idea:
https://www.goldfries.com/hardware-reviews/streacom-fc8-alpha-fanless-casing-review/2/
 
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SylphAudio

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But hardly with this cooling... Just a few loose thoughts:
Not being a fan of fans and their noise, the thing that bothers me a bit about many "chip amps" from several manufacturers, are the "miniature" radiators. A decent size radiator would eliminate the need for a fan, and provide lower operating temperatures, prolonging the life of the chip(s), wouldn't it? Having a small enclosure is fine, but it's not really difficult to place a radiator on the side, or top of an enclosure, with free airflow, so much better than inside the box. May need a heatpipe in some cases. I would pay the extra "20$".
An example of the principle i'm referring to, no amp, a PC, but just to demonstrate the idea:
https://www.goldfries.com/hardware-reviews/streacom-fc8-alpha-fanless-casing-review/2/

The TPA3255 IC is actually smaller than most CPU die's thermal pad with TDPs of 95W.

Now if we apply 2x200W output continuously, it has to dissipate constant ~40W of heat through its 4mm x 7mm thermal pad.

So it tells us that continuous full power with sine wave is not possible with this chip. (of course there will be exceptions if we apply extreme methods)

My design choice for heatsinking is to use the same model that TPA3255 EVM uses, it can handle full power uncompressed music continuously and can be easily mounted or disassembled from the module.

Using 45V rails will make the EVM heatsink temp hover below 50 degC in open air conditions (with 30degC ambient temp). Using heavy aluminum case will help it cool as it absorbs radiant heat from the module's heatsink. Heatpipes or aluminum bridge can be routed from EVM ATS heatsink to chassis, but no one has done it yet.


1627541148681.png


1627541303355.png
 
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respice finem

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Maybe component longevity isn't too high on the priority list then ;)
On the other hand, most such amps will be operating in low power ranges most of the time.
 

Trdat

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So just confirm, is the TPA3255 the chip or the whole module?

I am trying to understand if I see another module with a TPA 3255 does that mean it's the same module as the one above or its only one part of it and the module is a specific design around the TPA3255? Hence every module being different and measuring different.
 

JohnYang1997

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So just confirm, is the TPA3255 the chip or the whole module?

I am trying to understand if I see another module with a TPA 3255 does that mean it's the same module as the one above or its only one part of it and the module is a specific design around the TPA3255? Hence every module being different and measuring different.
Chip. So can be very very very different.
 

typericey

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We have an EU partner to provide the complete / cased amplifier but it may take some time to go into production..

Congrats on a very good measuring product from a fellow Filipino! I'm not a DIY kind of guy so I'll wait for the complete/cased amp (with the same PS and soft start as tested by Amir so the measurements will be more or less the same) and will be happy to purchase. I do hope it will be locally available in Manila as well so that I don't have to order/ship from abroad.
 

laudio

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I am surprised so many on ASR have never heard of the TPA 3255. A lot of comments on how get it to 300 WPC lol like what is this chip amp. It's not a subwoofer amp BTW.

Fact of the matter is it measures very well per this review and sounds very good if you've ever built one using TI's EVM. I have a Hypex amp (perhaps not SOA but Teac's implementation which I like for other reasons with the meters and design) but my TPA DIY EVM could substitute for it just based on sound maybe with a few exceptions most likely due to power supply chosen.

Good job JLE for keeping with the EVM concept and trying to make it better. Hard to beat what TI did with that EVM.

Topping should really take take note here you are missing out on making a good amp.
 

Bruce Morgen

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Good job JLE for keeping with the EVM concept and trying to make it better. Hard to beat what TI did with that EVM.

Allo seems determined for its pending TPA3255 product to surpass rather than duplicate the TI EVM's performance -- not an easy goal, but their TPA3116 product certainly proved they can do things like that, so I'm looking forward to see what they can accomplish given a far more capable chip.
 

SylphAudio

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Hi. This doesn't make sense to me. Clipping voltage is bounded by the supply voltage of the opamps. If any, higher gain will bypass the input common mode range and give a bit higher output level for RRO opamps like opa1656.
Hi JohnYang,

You are right, after further experimentations, we have fixed the issue by changing PFFB network values. Now, using 36V DC it can reach 95W at 0.5% THD+N. And with 48V DC, the module can reach 196W at 0.5% THD+N. Stable without load connected :) There is some SINAD penalty, 2dB lower but the good news is that 2nd harmonic is now dominant.

Regards,
Lester
 

SylphAudio

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Allo seems determined for its pending TPA3255 product to surpass rather than duplicate the TI EVM's performance -- not an easy goal, but their TPA3116 product certainly proved they can do things like that, so I'm looking forward to see what they can accomplish given a far more capable chip.

I've seen some measurements done by their engineer in DIYAudio and it looks impressive. They will be using ultra low noise main power supply if I'm not mistaken.
 

Bruce Morgen

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I've seen some measurements done by their engineer in DIYAudio and it looks impressive. They will be using ultra low noise main power supply if I'm not mistaken.

Yes, in our brief correspondence that power supply was mentioned.
 

anphex

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I am having a mind debate about this package and an "old" Hypex UCD400HG HxR Stereo kit. How much is this preassembled kit? My Hypex kit was for my surrounds and want to put my finger on whether this one here would be a better value or the UCD kit. Mainly because I noticed the specs look somehow close if you discard the lower gain of this reviewed amp. Hypex Kit was about 600 € (700$) btw.
 

SylphAudio

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This is a DIY module and the final cost will depend on power supply, aluminum chassis, and accessories. If you value the aesthetics, then you need to put more budget on the casing.

As for the brand value, Hypex is Hypex no argument about it :)

I am having a mind debate about this package and an "old" Hypex UCD400HG HxR Stereo kit. How much is this preassembled kit? My Hypex kit was for my surrounds and want to put my finger on whether this one here would be a better value or the UCD kit. Mainly because I noticed the specs look somehow close if you discard the lower gain of this reviewed amp. Hypex Kit was about 600 € (700$) btw.
 
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Somebody, sell this amp as a finished product without a built-in power supply.
 
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