Anyone used a Benchmark ADC1? Reviews indicate it may sound close to the Ayre at about half the cost. |
I was also looking at this device for digitizing vinyl. What concerns me is the use of 5532 op amps at the analog input and output of the device. I have auditioned op-amps like this via the tape loop of my Spectral DMC-10 pre-amp and they definitely detract from the SQ when listening to a good vinyl source. I would prefer all Class A discrete circuitry (like the Spectral uses) instead of 50 cent op-amps.
Anyone know of a digital audio recorder using discrete class A circuits? I could look for op-amp substitutes, but the amps in this device are surface mount so they are not easy to replace with discrete device op amps, or even with dual/single op amp converters for the AD797 or OPA627 single amp surface mount ICs. |
DTC
The Ayre QA-9 you mention does have discrete (assumed class A) circuitry. It's easily double the cost of the Tascam and I am not sure if it's still available. Could not find any listed on 'Bay. The other issue is that the QA-9 requires a stand alone computer to formulate the final .WAV or .FLAC audio file, which is not that convenient. The TASCAM is a stand alone solution, which produces .WAV files on memory cards or USB media directly.
Did discover that Brown Dog does make a SO8 to SO8 surface mount adapter to allow two OPA627 op amps to replace a 5532 dual. In my tape loop listening tests with the Spectral, I have found the OPA627 to be pretty close to the vinyl source, with a small amount of loss of SQ. For recording of vinyl for casual listening playback, this may suffice, assuming the BD adapters don't create stability problems with the 627s. |
topten:
The TASCAM does not have the file size limitations of a "CD" recorder. You can build any size file if the media (USB thumb drive, HD, or memory card) is large enough (but will run into 2 GB file size partition issues since they use FAT file partitions).
Neither does the Ayre QA-6, because you stream USB digital to a computer.
Audio quality does become an issue, depending on how critical you are.
Fremer did a review of the Ayre QA-6 recently in March 2015 along with some other A/D converters such as the PS Audio Nuwave, Lynx Hilo, and M2Tech Joplin:
http://www.analogplanet.com/content/analog-digital-converter-files-identified-converters-profiled#wCSH81I66K8VFGXx.97 |
topten:
Also, MD (Sony mini-disc) is not a loss-less format. It is compressed, similar to MP-3. I also have mini-disc and would never equate this format with high end audio. So it would not surprise me that anything recorded to MD will sound flat and lacking in detail.
I have many recordings ripped from CD to Sony MD, and they don't even compare to the CD quality originals. I did it because MD is convenient on a portable device were I did not want the larger sized CD. I think it is better than MP-3. |
Topten:
I realize that, and was responding to your question about the use of a "CD" recorder for capturing vinyl LPs. CD media is limited to 700 MB. By CD recorder I am assuming you mean recorders that directly write to CD media.
Since most LPs are limited to < 20-25 minutes per side, you will only exceed this for a single 2 GB file for DSDIFF at the 5.6 MHz sampling rate! This is way overkill for LP recording, especially with IC opamp buffers in the input circuitry (they will limit the sound quality, not the digital capture conditions).
In fact, with 2 GB, you can record a 26 min .WAV file at 24bit, 192KHz. Since the longest single, uninterrupted song on a LP is usually under 20 min, there is no need to worry about splicing files larger than 2 GB together.
Also, those instructions are only for playback on the Tascam. I would convert the .WAV files to FLAC for playback on my music server and would never use the TASCAM for anything but the original A/D conversion. |
DTC
The QB-9 is the D/A. The QA-9 is the A/D.
I have yet to see a QA-9 for sale. I went ahead and bought a TASCAM 3000 on fleabay for $720 new. For that price I can afford to try some op amp mods. I think I can remove the 5532s and replace with OPA627s on a Brown Dog adapter. For my purposes, only the input buffer amps need to subbed out. Once I have the digital file, it will be played back in my Bryston BDP/BDA combo which uses Class A discrete analog stages.
If in the future a QA-9 becomes available, I'll consider it at that time, depending on the results I get with the Tascam. |
DTC
Did not look at the Korg 10R, but it does not appear to be significantly better than the Tascam 3000. It uses a different op amp (OPA1662) instead of the 5532, and has built in phono preamp (which I don't need or want, I'll use my Spectral DMC-10). Plus, it cannot record directly to digital media like a USB drive or memory card like the Tascam can. The Korg must be connected to a computer via a USB cable to save digital files. The Tascam is much more of a stand alone solution. I have not auditioned the OPA1662 vs the OPA627 so I cannot comment on that. |
Dtc:
I got my DA-3000 today. It has a large number of op amps, either 5532s or 2114s (JRCs version of the 5532). No matter. Sound quality is mediocre at best.
I did a test recording of Blind Faith "Had to cry today" because I have the UK vinyl LP and three different versions on CD (US Polydor 1986, German RSO 1986, and 2001 "deluxe edition"). The vinyl sounds better than any of the CD versions, so a faithful recording of the LP has a leg up. I recorded a 24 bit, 96K copy of the song direct from the outputs of the Spectral DMC-10 (what I listen to, not the tape monitor) and converted the .wav file to FLAC with dB Poweramp. I then A/B'd with all the CD versions and the LP playing directly.
The copy recording made with the 3000 could not hold a candle to the LP. Period. Not even close. It was not even as good as most of the CD versions (although these are all different sounding from the LP). Symbols, in particular, were "mushed" and distorted compared to the vinyl.
Actually quite disappointed. Swapping opamps is not really practical due to the large number. And what is worse, it appears all these amps are cap coupled with electrolytic caps. Without a schematic, modding is not even possible.
For making copies of rare, vinyl not released on CD, or maybe versions were the CD is unlistenable, maybe the DA-3000 will work. But don't expect that vinyl air and magic to come through in the recording.
And I also found out the DA-3000 will NOT record to USB drives, only CF or SD cards. It will not even function with USB HDs. It will only play back from a USB drive. So you have to record your files to an SD card and then convert it or transfer it to a USB drive on another computer. You can transfer files on the DA-3000 directly, but it very complex and slow. Better done on an outboard PC.
Looks like I'll be looking for an Ayre. |
jwm
There is nothing wrong with my system, except perhaps it is to good at resolving details.
All you have to do is hook up headphones to the Tascam to hear how bad it is. I also have an early production unit because the date programmed in was 6/28/2013! |
Rodge827
Unfortunately, the transformers only impact the output of the D/A stage, and have no impact on the input analog buffers (all those op amps) coupled to each other with electrolytic caps. Those buffers are between you signal source and what gets digitally recorded.
I can see their argument about the digital hardware only recording without the need for a computer. I may keep it just for that, but still use an Ayre or Benchmark to run digital into the Tascam bypassing its input stages. Although its kind of expensive substitute for a computer these days. |
DTC:
I suspect the Ayre will work fine. I am leaning toward keeping the Tascam for simply converting digital from an Ayre QA-9 or maybe a Benchmark ADC1 to .wav files, because the variables of the computer conversions of USB data streams are eliminated.
I think Audio Advisor carries Benchmark and maybe I can get one to try out. If it does not work, I'd be back to finding and (paying for) the Ayre. |
DTC:
Spoke with an engineer at Benchmark today. Extremely knowledgeable and very straightforward with me. When asked about the analog front end he told me they did extensive listening tests and originally settled on the AD797, but switched to LME49860 which was even better. He agreed the performance of the analog front end was critical to the sound quality. They use one electrolytic coupling capacitor in the entire chain, and it is triple bypassed with film caps and NPO ceramics (which is unusual due the cost of NPOs).
He mentioned that the 5532 is long outdated (fine in the 80's) but op amp development has left this part far behind.
He agreed that recording to the Tascam would be the preferred method, because some PCs with Windows OS can mess with the sampling frequency (using software driver frequency converters) and you may not even know it. There may also be hardware issues with the USB ports re data reliability. Remember that connecting a USB cable from a computer to an audio device enables high frequency noise an entrance to your audio device (unless you optically couple like Ayre does).
The Benchmark has a word clock output that can be hard wired to the Tascam word clock input to synchronize the clocks. The Ayre only has this on the uber expensive pro model.
So it looks like I may order one from Audio Advisors because I could return it if I don't like it. Not so lucky with the Tascam as the seller wants a 15% restocking fee, so I may keep it just as a hardware recorder.
Also, apologies to TOP TEN for high-jacking his thread. |
DTC:
I think Benchmark only outputs 24/96K via USB. It will output 176 and 192k via the AES/EBU and digital outputs (including optical). Another reason not to go USB (and record to the Tascam), if you want higher than 96K. However, I was told 96K may be the optimum sample rate and higher rates may not sound as good or better.
The other thing I discovered was the Benchmark has much more flexible input gain ranges. You can get up to 29 dB of gain, whereas the Tascam will give you a max of 12 dB. This was an issue due to the low output voltage of the Spectral with a MC cartridge, and the highest signal levels I could get were about -10 dBU at the peaks when recording an LP.
The gain is also set in the Benchmark via analog devices like switches, resistors, and pots. The Tascam uses digital methods as you enter the gain numerically in 0.5 dB steps via the LCD screen. |
JWM:
I guess we will just have to agree to disagree on the SQ.
When I get the Benchmark ADC1 USB and hook it up to the Tascam I'll report back. |
JWM
See the details under my post above on 11/8.
Yes, I recorded a cut from an LP at 24/96K in WAV on the Tascam. Converted to FLAC on my PC, but also listened to the raw WAV file as well. Compared directly to my system playing the identical vinyl LP and three other versions ripped from CD to 16/44.1K FLAC.
My playback system is Bryston BDP-1 to BDA-1 to Parasound JC2 for digital files; Phono is AT OC9/ii cart/SME IV arm/Technics 150 SLMKII turntable (modded with outboard PS)/Luxman MC transformer/Spectral DMC-10 phono preamp to Parasound JC2.
Significant detail in the phono was missing in the recorded digital file. It was obvious on an A/B comparison. |
Al:
I do have oscilliscopes and RF spectrum analyzers and I can assure you there is no RF leaving my Spectral preamp. The Spectral also has a special protection monitoring circuit that is designed to pick up RF leaving the amp. That circuit is not or has ever been active. Plus, I am pretty certain that RF feeding a JC2 would not result in good sound through the rest of my system.
Read my recent post on using the Benchmark ADC USB1. I won't repeat that other post here, but basically the Spectral was coupled to the Benchmark which fed digital AES/EBU to the Tascam. If Al is right, the same RF would have been transmitted to the Benchmark and the sonic results would have been the same.
But they were not. There was a dramatic improvement in sound quality (and yes, even through the headphones), so I am not buying the mystery signal theory.
Clearly, the Benchmark has a better designed and implemented analog front end than the Tascam, and one would expect it given the components used by Benchmark.
Components DO matter, and there is a general consensus that some opamps are better than others, and that copious capacitor coupling with electrolytic caps does impact the sound. Why else do people pay $300 for a Mundorf coupling film capacitor? It is also reasonably agreed that an AD797 will sound better than a NE5532.
There is no mystery here, and we don't need to make up theories of mystery RF signals to explain the observed differences. |
Al:
You do have a point, assuming that potential RF entering the Benchmark is somehow filtered differently so that it never gets into the digital bit stream.
I did notice my 60 Hz hum levels were lower when using the Benchmark. Same gain setting on the Spectral, same interconnects. I attribute this to a better common mode rejection in the Benchmark balanced input amplifiers, which may have an impact on your point above. |
JWM:
Let us know what you find out, particularly if you spring for an Ayre. |
