Sylph Audio FB100 Stereo Amplifier Kit Review

[pma]

It is a sample box for my testing, not something he is selling.

To me, the bigger box is definitely better choice than the very small box like the one used for AIYIMA A07. The binding posts in the miniature enclosures are so tiny that it is difficult to assure reliable operation and they also restrict the speaker bananas used.

 

[SylphAudio]

Gain.
Gain, gain, gain, the lower it is, the better for measurements, especially for the amplified noise.

It comes to a point that comparisons are not even fair sometimes.
Add low input impedance to avoid a little resistance thermal noise as well and you probably get into the "blue" range just fine.

Only to an extent for a TPA3251 PFFB, take a look at the 3e A5, the A5 has lower gain (16dB) vs Topping PA5 1st version (19dB). A5 also has a PBTL (dual chip) implementation which should improve the measurements (which it does in some areas), yet it can’t go past 105dB vs the 1st PA5.

If you lower the gain of A5 by 2dB, I bet the SINAD won’t go any higher.

Point is you can’t just lower the gain and expect better measurements other than the +N.

This graph is not coincidence, I didn’t even use the same inductor used on the PA5 and the A5.

 

[daniboun]

I have this:

View attachment 545398

just "on the way". Another TPA3255 implementation, priced at 49.50 EUR, + 10 EUR shipment cost. Let's see how it is going to behave.

I assume this choice was carefully considered? Do you have the measurements for this module?
If you like, I can share some very interesting links to some TPa325X modules with you.)

 

[ICIETDIYEUR]

Hello Lester

It’s a great success

Do you remember the project (with the 'D200MKII' PCB) I worked on a few years ago, for which I asked your permission to use your "visual style"?

Here are a few images to refresh your memory ->

In the following photo, which shows the top of the amplifier, I should point out that it would light up via a small LED visible through the ventilation slots; this served as a power indicator, as there was no other light on the front panel (a much more pleasant touch when you don't want to be distracted while watching videos with dark scenes in a dimly lit room) ->

Right in the center of the amplifier's interior, you can see the small PCB equipped with four LEDs; they are of moderate power but highly diffused (with no measurable impact on power supply noise) ->

I had also tested another implementation ->

1 - Aluminum chassis (with 'Faraday' shielding with three layers of aluminum mesh adhesive and insulation with high-voltage resistant adhesive)
2 - Gold-plated IEC mains inlet
3 - AC filter
4 - Soft-start circuit
5 - Switching power supply (48V/1000W/~21A)
6 - DC filter
7 - On/Off switch
8 - SYLPH D200MKII circuit board (with 'MOD' on the op-amp low-pass stage)
9 - Specialty cables (tightly braided + copper shielding)
10 - Gold-plated speaker terminals
11 - Gold-plated XLR connectors (with ground lift switch)

Whether referring to the first or second version, special attention was paid to the wiring: very tightly braided, triple-shielded, and double-insulated, with the shortest possible routing for the cables supplying power to the power PCB.

Note: When used with Klipsch RF-82 MK II speakers, absolutely no hiss was audible even with one's ear pressed right against the tweeter horn—with the volume set to maximum and no input signal, of course.

I regret not sending it to Amirm back then, since you had even suggested it to me, Lester

We had exchanged a lot of technical information back then

All the best, and perhaps we’ll be in touch again soon.

 

[witwald]

Please also link the source. As it is, "poor components" can be anything from incorrect values to out of spec components. The graph alone doesn't do much here.

The caption with the graph specifically notes that the component values, and the resulting filter response functions, were identical. The description "poor components" would seem to be entirely reasonable. In their whitepaper, KEF also stated that: "For The Reference, extensive objective testing of individual components were carried out to identify those with the lowest distortion." This would imply that objective measurements were undertaken, as is supported by the published plots of THD.

The document where the graphs were published is: https://assets.kef.com/pdf_doc/REF/REF-White-Paper-201219-LR.pdf.

 

[Chrispy]

Okay for a low power amp, but don't really want/need one now so not so interesting.

 

[Sokel]

Point is you can’t just lower the gain and expect better measurements other than the +N.

But that's exactly the whole point, noise.

As long as the distortion is at (ballpark) -110dB, it's the noise that defines THD+N (or SINAD if you prefer)

Moreover, the point is also general.
It's only a few years that gain has fallen so low, as even pro gear fed by 4V were ballpark 25dB-30dB gain (high power amps though mostly) and nearly all consumer ones were there as well.
You can tell by AVR's which tend to follow standards.

Nothing bad about it of course, it's only the comparisons that fall short.

 

[pma]

I assume this choice was carefully considered? Do you have the measurements for this module?
If you like, I can share some very interesting links to some TPa325X modules with you.)

The main reason was my curiosity what they offer at such very low price. €50 for 2-channel TPA3255 higher power module seems to be a good deal. I will have “some measurements” after the module is delivered, which should be next week. I do not expect any miracles, reliable operation at datasheet parameters would be enough to me. I will write a review after having it measured.

 

[pma]

Point is you can’t just lower the gain and expect better measurements other than the +N

Exactly.

 

[101geo]

This kind of nonsense means I will now look elsewhere.

Perhaps the PCB has an improved colour too?

They can hardly be expected to lock out the "Audiophile" sector can they? It measures well, leave the blurb for the guys that like that stuff.

 

[daniboun]

The main reason was my curiosity what they offer at such very low price. €50 for 2-channel TPA3255 higher power module seems to be a good deal. I will have “some measurements” after the module is delivered, which should be next week. I do not expect any miracles, reliable operation at datasheet parameters would be enough to me. I will write a review after having it measured.

Nice thanks ) looking forward to see your mini review. If you need a PSU check my previous pages I shared a link to a great one.

Check this as well :

NEW BRZHifi PAD-30 : Dual TPA3255 +PFFB @ $99

Hi amigos Just to share I found this new dual TPA3255 + PFFB. The price seems very attractive. Makes me think the 3E Audio A7 BTW. I wish Amir could test it. See attached files for details Main spec : PFFB Dual TPA3255 (seems to be a one chip per channel) Trigger Pre-out Upgradable Op Amps...

www.audiosciencereview.com

New Dual TPA3255 Module + PFFB / Fully differential / OP amps DIP8 @ Great price

Hi amigos, As usual, I'm sharing my little discoveries from the web. I made a good find, so I'm sharing it. I found a TPA3255 dual chip module with PFFB and DIP8 op amps at a pretty good price! SPEC : Dual Chip TPA3255 (PBTL) Version A : Fully Balanced Version B : SE inputs Power : 150W / 8R...

www.audiosciencereview.com

NEW Nvarcher TPA3255 Mono Module with Flat Inductors. Measurements inside. $35

Hi amigos, I'm sharing a little discovery at a very reasonable price. I found this module particularly interesting, even though it doesn't seem to have a PFFB circuit. The components seem to be of good quality, especially the flat coil inductors. This module reminds me a bit of the 3E AUDIO...

www.audiosciencereview.com

 

[daniboun]

@pma

BTW found this about your module see attached file

 

[RandomEar]

The caption with the graph specifically notes that the component values, and the resulting filter response functions, were identical. The description "poor components" would seem to be entirely reasonable.

No it doesn't. Otherwise I wouldn't have asked. The caption specifically doesn't say which component values were identical (only capacitance? Nominal or measured?) and if the caps even were of the same type.

In their whitepaper, KEF also stated that: "For The Reference, extensive objective testing of individual components were carried out to identify those with the lowest distortion." This would imply that objective measurements were undertaken, as is supported by the published plots of THD.

The document where the graphs were published is: https://assets.kef.com/pdf_doc/REF/REF-White-Paper-201219-LR.pdf.

Thanks for linking. The white paper also does not specify which values were matched or if different types of caps were used. There's really no hard data at all on what properties the compared components had. Which isn't too surprising since it's a marketing publication, not a scientific one. But it does say

Again, there were significant differences between different types.

which implies that they were testing totally different types of caps - as in electrolytic vs MKP for example - which have very different impedance curves. Which would explain why they performed measurably different in circuit.

So my original point still stands.

 

[Redacted]

They can hardly be expected to lock out the "Audiophile" sector can they? It measures well, leave the blurb for the guys that like that stuff.

It's an issue of company credibility if their marketing people get too colourful...

 

[pma]

@pma

BTW found this about your module see attached file

You are posting the data that anyone can find in the module datasheet.

 

[daniboun]

You are posting the data that anyone can find in the module datasheet.

Yes just to share )

 

[amirm]

It's an issue of company credibility if their marketing people get too colourful...

You have my independent testing data here. What credibility is left to worry about?

 

[michaelahess]

You have my independent testing data here. What credibility is left to worry about?

It's false advertising at worse, biased opinion at best. Neither is worth losing credibility over. Basically shouting "I'm a used car salesman!"

 

[Redacted]

You have my independent testing data here. What credibility is left to worry about?

It's the rocky road! Product may be great, but when marketing people get started, I worry about the future....

 

[pma]

They want and need to sell, that’s all . It is difficult, when the amplifiers sound almost same .