This is a review and measurements of the SylphAudio’s (formerly called JL Electronic) Sylph-D100 P02 stereo amplifier module. Price is $119.00 USD or $128.00 USD depending on the OP amp you choose. Shipping to my country (Japan) was $20. Its sister model, Sylph-D200, was once reviewed by Amir (@amirm ). The Sylph-D200 uses TPA3255, an amplifier IC from TI, while the Sylph-D100 uses TPA3251. P02 is the latest version of the Sylph-D100.
Configuration of my Sylph-D100 P02:
- OP amp is JRC 4565D. (Another option was OPA1656, but it was out of stock when I ordered.)
- I chose Balanced mode. (You can configure Balanced or SE by a solder jumper.)
- I used Mean Well LRS-150-36 for power supply. (Syph Audio recommends SMPS 200W or higher. But I used a smaller one – 150W.)
- Post-filter feedback (PFFB) is enabled by default.
Note: Sylph-D100 version P02 has a different input pin layout than the previous version. 1) GND, 2) IN+, 3) IN- as below. Be careful, the red wire is GND, the black wire is IN+ and yellow wire is IN-. Use IN+ and GND for SE input (IN – is not used for SE).
Measuring Equipment and Methods
I do not have professional instruments like AP, so I used the following equipment and software for my measurement.
- E1DA Cosmos ADC
- TOPPING D30Pro DAC
- Self-made Low-pass filter (LPF)
- Dummy Loads 4Ohm and 8Ohm
- Room EQ Wizard (REW) software
My measuring method is described here. Not only do I not have professional equipment, but I am not an audio measurement expert myself. Though this method was reviewed by Ivan from E1DA ( @IVX ), there might be some mistake in my measurement. If there is an error, it is my own fault.
Sound quality and power are affected by configuration. Below is some feedback from Lester from SylphAudio ( @jlesterp ) when I shared my measurement results with him.
- “If you use OPA1656 / OPA1642, the SINAD will get 1dB to 2dB more because of fet input lower noise on higher value source resistors.”
- “Regarding the sound, I think SE mode has a more pleasing sound.”
- “You can safely set the power supply voltage to 38V DC. You can get 100W at 4ohms with that power supply voltage configuration.”
Sylph-D100 P02 Measurement
THD+N and SINAD
This is a little different from the standard ASR dashboard, but I will show you from a similar dashboard. I drove both channels and measured each channel. As you see, SINAD is superb – 100.8dB (Left) and 99.3dB (Right). The 2nd harmonic is larger in the right channel than in the left channel. But the distortion is not audible anyway, so I am not too concerned about it. N (noise) is -102dB to the signal level in each channel, it is very clean. Input to Sylph-D100 P02 was 1.12 Vrms, so the gain is low – about 4x or +12dB.
The next graph is THD+N vs Level @4Ohm, with both channels driven. I took two measurements just to be sure, but the results were consistent. The numbers below the graph are THD+N at 5W. Again. Left channel THD+N at 5W is about 1dB or 1.5dB better than the Right channel. Max Power is about 70W-4Ohm with my configuration. Because input sensitivity of Sylph-D100 P02 in Balanced mode is 5 Vrms, my TOPPING D30Pro DAC, which is 0dBFS = 4 Vrms, cannot get the real max power of the amplifier (so, 150W SMPS is enough for my configuration). Also, supply voltage to Sylph-D100 P02 can be maximum 38V. Using another SMPS (KIKUSUI PAS40-18) and an Audio Interface (MOTU M4, 0dBFS = 5Vrms), I confirmed that Sylph-D100 P02 generates 100W-4Ohm. PAS40-18 supplied 38V/5.38A = 204W to the Sylph-D100 P02 at the time.
The next one compares THD+N vs Level into 8Ohm and 4Ohm. As I have only one 8Ohm load, only one channel (Left channel) was driven. SINAD is 102.4dB at 5W into 8Ohm, but the max power is 35W. If you have sufficient power supply, you can get 50W-8Ohm.
Frequency Response
I checked Frequency Response sending about 1Vrms (0 dBV) signal. Frequency response is essentially flat. The numbers below the tables are dBV at 20kHz. There is small load dependency: 0.2dB @4Ohm and 0.4dB @8Ohm.
Dumping Factor
I sent the same level of signal, but as you can see, the voltage is slightly different between 4Ohm and 8Ohm. I calculated the output impedance of Sylph-D100 P02 at 1kHz using the resistance of the dummy load (3.98Ohm and 7.96Ohm to be exact) and the voltage. The calculated output impedance was 52mOhm, so the dumping factor is 155 for an 8Ohm speaker, quite good.
Stereo Crosstalk
I drove one channel with 1V (0 dBV) and 10V (20 dBV), then measured frequency response of the driven and undriven channels. Difference of the two channels should be stereo crosstalk. As you see the graph and the table, crosstalk performance is very good.
IMD and Multitone
Checking SMPTE standard (60Hz and 7kHz) Intermodulation Distortion (IMD), the two signals are nicely separated. IMD is -92.3 dB, TD+N is -101.0 dB.
The result of the multitone test is quite similar to the results of the Sylph-D200 measured by Amir. It shows the classic rise of distortion with frequency.
Listening test
I have two sets of small standmount speakers - Revel M105 and custom speakers (woofer: Audio Technology 15J52, tweeter: Dayton AMT1-4). As expected, the Sylph-D100 P02 drove them well. Its medium power is enough for these speakers. I found the Sylph-D100 to be clearer and more detailed than my classic Class AB amps. As this was not a blind test, so it could be a placebo effect. Anyway, sound from Sylph-D100 and my speakers is pleasant to me.
Conclusion
I spent about $250 for Sylph-D100 P02, power supply, aluminum enclosure, terminals and wires. It is amazing to get such a high performance amp for that price, even though it is a DIY. By the way, Amir mentioned in his review of Sylph-D200 that “Interacting with member @jlesterp has been a delight as well.” I agree with his comment. 
It may be difficult for the average audiophiles to assemble. However, as we are in the “DIY Audio Forum”, I recommend the Sylph-D100 P02 amplifier module.
