Benchmark LA4 vs Bryston BR20 (Stereophile vs Sounstage measurements)

[Rischa]

Comparing the Bryston BR20 preamplifier and Benchmark LA4, I noticed that Stereophile measured the LA4’s a-weighted SNR as 105.5dB vs manufacturers spec of 137 dB, while Soundstage measured the Bryston BR20 A-weighted SNR at 109 dB vs manufacturer spec of 110. Would this indicate that Soundstage’s measurements are more accurate, or that Benchmark’s specs are inflated?

Links to the test results:

Stereophile LA4: https://www.stereophile.com/content/benchmark-la4-line-preamplifier-measurements

Soundstage BR20: https://www.soundstagenetwork.com/i...atid=433:preamplifier-measurements&Itemid=142

For further context, I’m cross-shopping the LA4 with the Bryston BP19 preamp, which is a BR20 without streamer and DAC. I was originally planning to just get the LA4 but noticed the Bryston specs are comparable, and used BP19s are about the same price as a new LA4.

 

[Kal Rubinson]

This means nothing without a common control.

 

[Martini]

I can tell you the Benchmark LA4 is stellar. I can't tell you the Bryston is not.

 

[Rischa]

This means nothing without a common control.

Yeah I understand. I’m just trying to understand the available info on these two preamplifiers so I can make the best decision. The discrepancy between the benchmark measurements and manufacturer specs stood out to me, but there could be something I’m misunderstanding in the measurements or how they were performed. I’m a beginner to objective audio but trying to learn.

 

[NTK]

For the Stereophile measurement of the LA4, the differences are that Stereophile (John Atkinson) measured the SNR at 1 V output and the 105.5 dB number was unweighted. Benchmark's spec is for full output of 20 V and A-weighted. The signal level difference of 20x will account for a difference of 26 dB. JA's measured A-weighted SNR was 108.7 dB. Accounting for the 26 dB level difference, it should raise the LA4 SNR to 135 dB (= 109 + 26), which is only 2 dB short of Benchmark's spec.

Benchmark Spec:

Stereophile measurements:

 

[Martini]

Amir, reviewed the HPA4 which is a LA4 w/Headphone amp. The review covers both Pre-amp and Headphone-amp, so you can skip-over reading the Headphone measurement results, if you what. Bottom line though is, both sections are superlative.
https://www.audiosciencereview.com/...nts-of-benchmark-hpa4-headphone-amp-pre.8141/

 

[MAB]

I tested an old Bryston BP-25, using the same dashboard Amir uses. My analyzer isn't as good as Amir's.

That being said, the preamp tests better than the spec sheet it was shipped with ~30 years ago. That's because the analyzer Bryston used back in 1990 was worse than mine is.

All of this is immaterial since the preamp still tests really well.

Either the LA4 or the BR20 are going to be nice. Benchmark is certainly one of the leaders in noise and distortion. Bryston has a great reputation too, especially reliability and after-sales support.

I really can't see how you could go wrong between the two, unless you have some very specific I/O needs. Or just like one vs. the other.

 

[EL_PW]

I tested an old Bryston BP-25, using the same dashboard Amir uses. My analyzer isn't as good as Amir's.

That being said, the preamp tests better than the spec sheet it was shipped with ~30 years ago. That's because the analyzer Bryston used back in 1990 was worse than mine is.

All of this is immaterial since the preamp still tests really well.

Either the LA4 or the BR20 are going to be nice. Benchmark is certainly one of the leaders in noise and distortion. Bryston has a great reputation too, especially reliability and after-sales support.

I really can't see how you could go wrong between the two, unless you have some very specific I/O needs. Or just like one vs. the other.

I would be ecstatically happy to own either one. Or both.

 

[Rischa]

I went with the LA4 to match my DAC3 B. Not only the best measuring dac and pre I’ve owned, but, subjectively, the best sounding. They drive my also new Buckeye 2-channel Purifi amp.

When I started in this hobby about 15 years ago, my first “high-end” gear was a 2wpc single-ended tube amp and Tekton speakers (purchased on advice from the kind folks in the Audiogon forums). I convinced myself it sounded great, lol. If I knew then…