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Amplifier Modules and PCBs For Sale

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#1,421
454Casull said:
I didn't figure a product all about measured performance was also going to be catering to op-amp rollers, but to each their own.
Click to expand...
I think the tradeoff (and the 4.1x gain) will be justified once you've listened to the Sylph-D100. 🙂 A DAC with 4Vrms output is enough for large room listening.
D200 might be discontinued since I think the D100 has a better midrange sound, and we will retain the D400 for higher power applications.
 
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#1,425
Any chance you will develop an outboard gain stage to be used with your low gain amps, a la Topping PA5? I wouldn't need unbalanced inputs but EMI filtering, easily-swappable (e.g. through-hole) resistors for gain, etc. should be available.

The assembled offerings from Neurochrome, Kaltecs, etc. are obviously well-designed but quite pricey, especially since they require a separate low-noise power supply. I would be interested in 1 or 2 of your TPA3251 boards if it was easy to boost the incoming line level (in a practically distortion-free manner) to maximize the power output.
 
#1,427
454Casull said:
Any chance you will develop an outboard gain stage to be used with your low gain amps, a la Topping PA5? I wouldn't need unbalanced inputs but EMI filtering, easily-swappable (e.g. through-hole) resistors for gain, etc. should be available.

The assembled offerings from Neurochrome, Kaltecs, etc. are obviously well-designed but quite pricey, especially since they require a separate low-noise power supply. I would be interested in 1 or 2 of your TPA3251 boards if it was easy to boost the incoming line level (in a practically distortion-free manner) to maximize the power output.
Click to expand...
Yes it is already planned but needs a few months to develop.

I have changed the input stage design on the upcoming Sylph-D400 (all SOIC ICs, separate gain + buffer stage, 4 layer design on the whole board), now the total gain is 16dB (6.3x voltage gain) so that a 4Vrms input signal can drive the output just below the clipping point. (ETA 3-5mos)

Presently for Sylph-D100, the buffer's gain can be reduced by changing 4pc 0805 resistors. (input stage currently at 3x, multiplied by PFFB gain at 1.367x for a total voltage gain of 4.1x)

I tried to increase the buffer's gain but on listening tests, I detected some "hardness" on the sound, so reduced it to 3x. Once the gain board is available, users can reduce the D100's buffer's gain to 1.46x for a total of (6dB) 2x voltage gain when PFFB is enabled. Or can be completely bypassed altogether.


1688815197985.png
 
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#1,431
454Casull said:
Hmm... rather than doing the gain on a discrete piece, would it be instead possible to revamp the preamp section on the amp itself to optimize its SINAD performance? Or is the physical proximity to the amp part of the issue?
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I didn't understand the question? In order to optimize the preamp section, it requires at least a 4 layer PCB and SOIC opamps.
With the current design of Sylph-D100 and D400, voltage gain of <= 3x for the preamp is a good compromise for SINAD performance.
 
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#1,433
SYLPH-D400
Without heatsink / Without bulk caps option is being tested as well before shipping out. Only the heatsink and bulk caps are required to make it an RTR module.

Compatible heatsink
ATS-TI1OP-519-C1-R3 or
ATS-TI1OP-519-C1-R0

Recommended cap (63V, 18mm diameter, 7.5mm LS)
EEU-FC1J182

JRC4565 is the default opamp going forward.
 

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#1,436
Yes the Sylph-D100 P02 uses a similar implementation. Also I know the same PFFB implementation even before it was posted.

Though Gamerpaddy exposed the 4layer PCB implementation, next level reverse engineering lol.
 
#1,438
454Casull said:
Interesting stuff going on here
Click to expand...
If you have gamerpaddy's module, just bypass the opamp section of D400 or D100 (solder a wire from the input terminals then solder it directly to input coupling caps, attached pic). It will perfectly work. Although you need OPA1612 and good 4 layer layout on an external module to get 106dB SINAD (5W 4R) on both D100 and D400.

The input section of D100 and D400 have a different implementation, but it should sound the same (if not better). So there's no point of bypassing the input section other than achieving higher SINAD (or higher gains)

connection.png

3.png
 
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#1,440
Sylph-D400

Power output before the LED clipping indicator lights up, no aggressive protection / shutdown even on hard clipping.
Should not go into protection mode even on 2Ω subwoofer duties.
4Ω 5W SINAD = 99dB

1kHz power measurements using 52V DC supply
  • 115W-8Ω
  • 219W-4Ω
  • 378W-2Ω
20Hz power measurements using 52V DC supply
  • 112W-8Ω
  • 215W-4Ω
  • 326W-2Ω
 
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