Chasing perfection on the cheap

[newbie-]

TL;DR: Why am I doing this to myself? And do I really care at all about pots vs stepped attenuator?

Two weeks ago I purchased some Klipsch RF7-II speakers and a Marantz SR6013 to power them... and I caught the bug again. To be honest, I really liked the sound from the Marantz. It was smooth, warm, and I just didn't get tired of it. Music sounded I know sounded like I'm listening to it for the first time. So my curiosity went in to overdrive... what sorcery is this??? I picked up an Onkyo TX-SR393 at Best Buy for $250 and set it next to the Marantz and benchmarked the two for fun. The Onkyo has a very different sound... much, much brighter. That's interesting.

After reading the relatively poor reviews here on even the flagships from Marantz, I set out on my fools quest to try and beat their flagships. And as a challenge, do it for a small fraction of the price.

I don't need 11 channels of audio. I don't need THX, Dolby, etc... I just want excellent stereo. By day 2 I had made some decisions:

1. The budget should be around $600 total.
2. Must be at least 100w/channel in a stereo setup.
3. The best of (reasonably priced) "state of the art" class D chips: TPA3255EVM amplifier.
4. The very best of inexpensive DACs: WesionTEK Khadas Tone Board DAC.
5. Digital room EQ and calibration at the audio source.
6. Minimum number of electrical components.

I've got a problem here... there's no volume control in the circuit. So down the rabbit hole I go.

Preamps: Breaks my #5 rule. Too much crap in the signal path.
Stepped attenuator: $300 for volume control. Breaks rule #1.
Potentiometer: Take the poison... Possibly ALPS Stereo Potentiometer.

Let me be totally honest here. My source of entertainment is mostly Youtube and 60% "youtuber" amateur content, with a dab of Amazon Prime/Netflix, and Spotify music in the background... The audio source is already compromised.. Youtube at worst and compression on Spotify at best.

So should I really care enough to worry about the harms of a potentiometer?

 

[RayDunzl]

Potentiometer: Take the poison... Possibly ALPS Stereo Potentiometer.

I used a pair of pots for a long time to avoid any channel imbalance that a stereo pot might have (after using a stereo pot).

CD player and amplifier and speakers was the whole system.

Place it in the center, adjust by ear. It's easy enough.

 

[TimW]

Why not just get a DAC with volume control? Or use software volume control since you plan to use it for digital EQ anyway.

 

[newbie-]

Why not just get a DAC with volume control? Or use software volume control since you plan to use it for digital EQ anyway.

Adjusting software volume control (Windows) isn't an option as it affects sample rate and bit depth. Please correct me if I'm wrong on that

Any recommendations on a DAC with volume control? After browsing the list, the prices go up pretty quick to $450+ if it's even still for sale.

I could spend the money. But the point of this challenge is to keep it under a budget.

 

[RayDunzl]

Adjusting software volume control isn't an option as it affects sample rate and bit depth.

It doesn't change the sample rate.

You're unlikely to notice any degradation of the signal.

---

Visual example of Digital Attenuation:

Full digital volume vs -60dB waveform (24bit), or 1/1000th the original voltage level coming from a modern DAC.

Hint: -60dB is like going from normal level to near silence.

 

[newbie-]

It doesn't change the sample rate.

You're unlikely to notice any degradation of the signal.

Interesting. I'm following the advice here:
https://www.audiosciencereview.com/...th-or-reality-volume-control-in-windows.2031/

Specifically:

I don't know about it being worse than Mac or Linux but yes, using the volume control or the Windows stack will measurably degrade performance. I plan to show that in a future article.

Is this not true? Could be that a potentiometer is even worse than adjusting Windows volume.

 

[TimW]

SMSL Sanskrit 10th MKII

Volume control via included remote for $109.99 on Amazon right now.

 

[newbie-]

SMSL Sanskrit 10th MKII

Volume control via included remote for $109.99 on Amazon right now.

Purchased. Arrives Tuesday. Thanks for the heads up!

 

[RayDunzl]

Is this not true?

Measurably degraded and audibly degraded are not the same thing.

Purchased.

Well, yer done.

 

[TimW]

Hopefully you like the look of that SMSL because the Topping E30 is another great option for only $20 more.

 

[newbie-]

Ah looks are not a factor for this adventure

With the DAC sorted I am questioning my choice with the TPA3255EVM amp. This is a reference board from TI intended to demo their tech and provide a recommendation for design of the circuit.

The 3255 is a very well regarded chip... From my research, it's one of the best in its class. Hopefully the components on the reference board are pretty good.

http://www.ti.com/tool/TPA3255EVM

Are there any other Class D amps in the 2 x 100w range I should also consider? (In budget of course)

 

[TimW]

The TPA3251 is also pretty good. Check out this comparison to the TPA3255.

 

[newbie-]

For the TPA3251 this seems to be the one to get: https://www.ebay.com/itm/333125279929 Crazy how cheap these are. $65 and a power supply. What's the catch?

Since the DAC was so inexpensive I've got a pretty good budget for an amp. At least $400 more to spend to try and match or defeat the Marantz I've set as the benchmark. I've got the TPA3255 on the way to try first.

If I like the SMSL Sanskrit 10th MKII then I'll probably buy the SMSL M400 next.

If this works out... The next phase of this experiment may be to try and integrate surrounds for a 4 channel setup. I've got some Klipsch RP-500SA atmos speakers sitting around unused. But this is a problem for the future.

 

[Xombul]

For 600 $ and a pinch of DYI:

Smsl da-8 (or Audiophonics mpa s125 nc-but it is more expensive)
Umik 1 + rew
Raspberry PI 4 + Volumio + drc plugin
Audiophonics dac ak4493 (or ess 9038 q2m) board for raspberry or Khadas board.
Pionneer ps bs22 lr+ mod (or Philharmonic Audio Affordable Accuracy monitor)

 

[newbie-]

Alright! The DAC has arrived. I'm excited to plug it in and see what it can do. Unfortunately, my unit appears to be damaged. The display has a chip and scratches.

I've been itching to buy some of the more expensive S.M.S.L units. But my confidence in the brand is shaken and I'm not sure I'd recommend it to a friend... Hopefully the guts inside are on spec.

 

[somebodyelse]

As you've already linked to one of the 3E boards you should probably check out the complete amp they've recently released. No measurements so far, and I don't know how you feel about everything going through the onboard DSP's ADC and DAC. The web page seems to be a work in progress too.

 

[JeffS7444]

I picked up an Onkyo TX-SR393 at Best Buy for $250 and set it next to the Marantz and benchmarked the two for fun. The Onkyo has a very different sound... much, much brighter. That's interesting.

In case you haven't already done so and don't have a subwoofer installed, don't forget to configure the Onkyo to "Subwoofer: No" else it assumes 100 Hz crossover frequency!

 

[ernestcarl]

SMSL Sanskrit 10th MKII

Volume control via included remote for $109.99 on Amazon right now.

I have my eye on this as my Cambridge DAC 100 just recently died. Need a cheap replacement.

 

[ernestcarl]

Alright! The DAC has arrived. I'm excited to plug it in and see what it can do. Unfortunately, my unit appears to be damaged. The display has a chip and scratches.

I've been itching to buy some of the more expensive S.M.S.L units. But my confidence in the brand is shaken and I'm not sure I'd recommend it to a friend... Hopefully the guts inside are on spec.

View attachment 67868

View attachment 67869

Hopefully, it works alright. I've kept items shipped and received in worse conditions.

 

[newbie-]

As you've already linked to one of the 3E boards you should probably check out the complete amp they've recently released. No measurements so far, and I don't know how you feel about everything going through the onboard DSP's ADC and DAC. The web page seems to be a work in progress too.

Nice. Thanks for pointing that out. The 3255 version doesn't appear to be available to purchase.. At least I can't select it for checkout. But I'm glad to see a potential option.

How the heck is this under $100 with an integrated power supply... and I just paid $175 for a bare module board from TI.

I'm expecting the TI module to outperform since the power supply is isolated. But only time will tell