i just did what you mentioned. But the real huge difference is getting a good preamp like the LA4 to go with it. It doesn’t add ‘ magic’, it just sounds bigger and way better.
You have to pay attention to the connector types and operating levels. Depending on the specifications of the source and sink, you could have very low signal level or overload. If you are mixing balanced and unbalanced equipment, you will lose any benefit from balanced operation.
Thanks! Looks like most folks are running consumer XLR and RCA into the LA4 and adjusting the boost accordingly. I was thinking of using the Chord Quest (unbalance outputs only) with the LA4 and ABH2. I think this just means I need to boost by about 16dB +/- ( 15.8dB the default boost for unbalanced, according to the LA4 manual) and that's it. If I use a short RCA cable, say 3 feet, this should not be performance limited, correct? @Tone? I think your thread is about to cause me to spend a lot of money. =D I was originally considering Purifi-based power amp like the NAD C298 before finding this thread. Did you demo any other amps before you tried the ABH2? Also how is the low level listening performance?
What do you mean here? Do you mean noise and interference characteristics due to the cable itself or is there a larger implication across the chain? That's right, I think the default boost for unbalanced is 15.8dB and then you can adjust if needed.
A balanced system involves differential circuits to counteract common noise signals picked up in transmission. The measure of how good a differential circuit performs is the Common-mode Rejection Ratio (CMRR): Common-mode rejection ratio - Wikipedia In an ideal balanced system, you would see: V(+ve) + Noise on one input and V(-ve) + Noise on the other input, where V(-ve) = -V(+ve) The ideal differential circuit will then create the output as V(out) = V(+ve) + Noise - {V(-ve) + Noise} V(out) = V(+ve) + Noise -V(-ve) - Noise V(out) = V(+ve) + V(+ve), since two minuses make a plus So, all the common noise is removed, and we are left with only the signal. Unbalanced circuits do not have this ability to counteract the noise, so when you mix balanced and unbalanced you are effectively undoing the benefit of balanced operation. In practice, differential circuits are NOT ideal, so some small portion of the noise will remain (and the CMRR is a measure of this). This is why (a) all balanced circuits are not created equal, and you have to pay attention to the quality of the implementation, and (b) in low-noise environments, unbalanced operation could be better!
Yep, I’m running both XLR inputs from Marantz SACD player and RCA inputs from an Amazon Fire Stick (running separate HDMI to RCA converter) into the LA4 and they are both working great. Low-level listening is great and response is very linear. Also, there are so many steps in the LA4’s gain control that you can always find the right volume.
Thanks for the detailed answer, this hobby is turning into a night school course. Apparently the LA4 tries to mitigate the problem, according to the manual: "The unbalanced RCA inputs on the LA4 are connected to balanced receivers. These balanced receivers provide significant immunity to ground loop induced hum and buzz. This topology provides the RCA inputs with some of the advantages of fully-balanced interfaces." I think the best I can do, besides considering a different DAC, is keep the RCA cables as short possible.
Hi @Helom, I am considering the Freya+ and the Benchmark ABH2, did you try Differential buffer mode on the Freya+ when you were comparing against the LA4? What did you think of it (I know that was a while ago)?
I didn’t compare them back to back. However, of all the Freya+ operating modes, I liked the buffer the least. It’s best in passive mode, but then you have zero gain (buffer provides hardly any gain also). The Bel Canto Pre5 was clearly better than the Freya+ in any of its modes, and the LA4 is marginally better than the Pre5. If I were to buy a Freya, I would buy the S since it has discrete nested feedback similar to my Topping A90D.
Thanks, The Bel Canto Pre5 wasn't on my radar but I'll check it out. As for gain, it's pretty clear what the Freya S/+ gain settings are but it's a bit confusing what the LA4 gain settings are (maybe this is a topic of another thread). Did you end up keeping both the LA4 and ABH2?
Does anyone know the gain on the LA4? I tried to find some info on its gain and couldn’t. Does it use gain in place of volume?
I think it uses gain and not volume. If you use unbalanced inputs it will by default boost the level by 15.8dB and they say that equivalent of rotating the volume control. On the website they specifically refer to a 256 step gain control. I'm a bit confused as to how this works relative to the 128-step relay-switched volume control in the Schiit Freya S/+.
The max gain is 15dB. “0” on the panel is unity gain. I’ve moved on from the Benchmark products because I found an amplifier I prefer to the AHB2. I sold the LA4 to free up some cash after getting a Topping Pre90. They are great products but in my opinion most speakers benefit greatly from power beyond 100/200 WPC, 8 ohm /4 ohm amps. If you’re in a small room with fairly efficient speakers then one AHB2 will suffice. It is attenuating the source until it reaches levels above “0,” at which point it is amplifying the signal. Fifteen decibels (30 0.5dB steps) is the max gain beyond the output of the source component. Because the LA4 has twice the volume increments/resolution of the Freya. Other than a couple suggestions on the ASR forum that the Freya S is a budget LA4, I don’t get why these two preamps are so often compared. They are in different leagues, both in operation and in sonic performance. Only in pipe dreams is the Freya a worthy substitute for an LA4. Those wanting LA4 sound on a budget should get the Topping Pre90. But it limits you to single-ended operation since the input impedance of the Pre90’s balanced inputs makes them practically useless. Luckily the single-ended operation of the Pre90 is plenty good.
Thanks! I didn't see this in the manuals or anywhere in the specifications but I could have missed it. You are right it's probably wishful thinking. This is true in my case along with the desire to experiment with tubs on the Freya+ to get a bigger soundstage. I think I'll have to put that idea to bed if I want to take full advantage of the AHB2.
Has anyone tried Benchmark speaker cable with their Benchmark amp? https://benchmarkmedia.com/collections/cables/products/benchmark-speaker-cable-nl2-to-banana-2-pole or tried Benchmark XRL cables between their balanced preamp and the Benchmark amp? https://benchmarkmedia.com/collections/cables/products/benchmark-starquad-analog-xlr-cable If so, what were your thoughts on either or both of them?
Not speaker cable but I do have there XLR cables between amp and pre and they sound fine. Haven’t really tried any other XLR cables so I haven’t made comparisons. but they’re well made Canare star quad cables.
I use Benchmark XLRs between the DAC3B, HPA4 and AHB2. I previously used Shunyata Venom XLRs between a RME ADI2FS and the AHB2, but when I added the DAC and pre I decided to build the whole stack with Benchmark gear, cables and all. No complaints at all, haven’t even been tempted to swap the Shunyata back in to experiment. No experience with the Benchmark speaker cable.
