Is your AVR digitizing your analogue signals? It probably is!

Just thought i would post this up as i made a few posts in a thread about entry level turntables recently and a few people were surprised by this, as was i when i first found out about it.

If you are using an AVR with your turntable there is a very high chance it is running all analogue signals through an ADC DAC (analogue>digital>analogue) process in the volume control, therefore ruining your turntables signal.

Even expensive units with a phono input will do this, only some high end models with a bypass function actually keep the signal analogue (i know a few marantz models offer this and yamaha).

There are a few ways to check this i will detail below:

* Play your TT then try to turn on dolby pro logic or Neo6 etc, if it still makes sound then your signal is being digitized

* Open your unit and look at the area behind the volume control, if its a standard volume pot theres a chance it is keeping it analogue (run the test above), if theres no volume pot its digitizing your signal

* If you can control the volume by remote that is a sign but not a giveaway sign, some units are controllable by remote but use a motor to turn an actual pot inside the unit, other units (Rega integrateds, i dont know if higher priced AVRs do this) use a set of stepped resistors that are selectable by remote but keep the signal analogue

Basically if you are running an AVR check these things and in 99% of cases i think you will be disappointed, even higher priced units will do this, my $1k Harman Kardon AVR digitizes all inputs, my old late 90s Kenwood also digitized all inputs.

I think this is a very important bit of info that a lot of people getting into analogue dont know about and its very hard to find info about.

If you are running a budget system and find out that your AVR is in fact digitizing, go and buy a cheap integrated stereo unit and this will solve your problem, i have listed a few options at modest price points below.

Rotel RA02, RA01, RA931 MKI or MKII, older RA820s and 930ax units, all of these you can find between $50 and $200. You may even be able to get an older Rotel Pre/Power separate system at around $400 - $500. Marantz and NAD also have very good cheap options at the same price points but im not familiar with their models. Next step up would be one of the older Rega amps, Brio/Mira/Elex clamshell, Brio 2000/Brio 3/Mira 2000/Mira 3 (Mira 3 starting to get up a little in price). The Rega units will be between $200 and $500. The sweet spot is the Brio 3 price/performance wise, $250 - $350 and a step up on other models although ive not heard a clamshell elex but it might be up there. Mira 3 i feel is a good step up in detail and is a little more refined than a Brio 3 and will cost $400 ish. I for the moment have chosen to stick with the Mira 3, for $450 used i dont think you can do better. The Rotels are rather clinical sounding great detail with forward mids/treble, bass is good and fast but doesnt dig as low as most Marantz and i think NAD offerings. However Marantz has a darker less clinical sound, NAD i cant give an acurate opinion on. If you can find one then a Musical Fidelity A100X may indeed be the best option if you prefer a warmer even boarding on tube like sound as they are almost entirely class A and they also offer MM and MC phono inputs, be warned though they run crazy hot and finding a non cooked used one is a lottery.

Cheers.

 

I have a Pioneer Elite SC-25 I run with my turntable. The Pioneer will only access these sound modes with digital connections. I run my turntable in Analog Direct Mode.

 

True i should make it clearer in my post. If your AVR doesnt have a HT Bypass button (or analogue direct various brands call it different things) then the 3 options i listed above are valid, if it does have HT bypass then you are all good. Most people getting into turntables who already have a surround system probably arnt aware of this however.

 

I've been using an Anthem MRX-710 or, currently, a Statement D2 pre/pro. If you want subs (bass management) and room correction, it has to digitize the input. It has an "analog direct" mode but it simply passes full range to the mains at that point.

In my experience, having had an "all analog" frontend for about a year before I consolidated down to the 710 (which is now moved upstairs, replaced by the D2), I wouldn't go without "digitization" as it were. At least in my specific case, the conversion to 24/192 internally has done nothing to make analog sound "different." It does no harm, in other words. Now, in all fairness, the D2 does a better job than the 710 but I chalk that up to better quality DAC and a much, much better analog section than the 710. The benefits of bass management and room correction were an absolute revelation in my small room, so it'll stay this way.

I also realize I'm talking about fairly highend "receivers" here but to be fair, I bought both used and really didn't pay all that much for either, in the grand scheme of things.

 

Don't most of these devices have an analog direct option to bypass processing? My cheap Sony 5.2 receiver has that option.

 

Many do and in my post above yours I explain one use case where that isn't an option.

 

I should have read the whole thread before posting . That Sony Avr does a good job with tv, but I'm sure glad I now have a rega mira for my turntable.

 

The Anthem receivers bring EVERYTHING into the digital domain, but still sound great. They insist that whatever the conversion does, the ARC more than makes up for it. No multichannel inputs offered as a result. I can't speak to the D2 though.

 

Given that SACDs put through a 44.1kHz digitizing ADC->DAC loop couldn't be ABX identified with statistical probability from the original, I think you're making a bit of an overstatement.
Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback pdf

The receiver may have both a direct path and a processed path (including digital time correction, EQ, crossovers - things that make your turntable sound better) and allow you to choose the former. Often this is a "pure direct" type switch.

Digitization on digital outs is expected, otherwise many consumers would be put off by silence when using them; it is not an indication of equipment's analog-analog purity.

 

No. Analogue direct is not the same as HT bypass. The former still routes the signal through the volume control while the latter does not.

 

A couple of other points worth noting. If your AVR does not have an analogue direct option it may have 5.1 or 7.1 analogue inputs. If it does then you can use the left and right inputs only for a phono preamp or other analogue input. Also most of my AVRs and the unit I currently use in my theatre (an Anthem AVM 50) also had an option to cut power to all the unnecessary circuits for analalogue direct (eg. Video, DSPs). I find this can also improve the sound.

As I have said before on this forum, IMO a used Anthem AVM 50 can be one of the best values out there for those who want to I expensively combine home theatre and 2 channel listening. Heck it also makes a darn fine 2 channel preamp with AD conversion and DA conversion available when you need or want it. It has one fully balanced analogue direct input and fully balanced outputs too. We can find these up in Canada on the used market for around 700 bucks. If you have a blu-ray player that will internally decode the newer hi-rez multi-channel soundtracks and output them as linear PCM then it is ready for those formats too.

 

LOL whether the volume control is an analog potentiometer or not doesn't determine whether your receiver is digitizing signals or not.

If your AVR sounds good and is using transparent AD-DA conversion (most of them are - often at high resolutions) then don't worry about whether the signal is being digitized (for bass management, EQ, room correction, etc.).

As with everything in home audio, the old axiom "If it sounds good it is good" applies here.

 

I've always used bypass with my TT input. But then I've never tested/compared that input being digitized. No reason to since my mains are full range. I first tested bypass mode(s) when SACDs hit the market in the early 2000s and realized the contrast - at least on my gear. So I've not messed around with it since. I will only buy a pre/pro that has some type of pure analog direct mode.

 

I use a late 70's Hitachi receiver for LP playback, so I highly doubt there's anything digital about it.

 

Unless you don't know what you don't know. I can't count the number of times I thought "it sounds good" until I heard better.

 

I still say that if you need an AVR, the best of both worlds is a dedicated power amp for the mains, and a 2 channel preamp with HT bypass for your audio.

 

Can't you tell by listening? If it sounds digital, then it must be digital.

 

I have an upper tier Pioneer Elite AVR but I just use it as a pass-through for my Spectral pre-amp. 90% of the time I use Pure Analog Direct, but I often have fun using some of the digital surround modes as an option.

 

I use a CJ ET3 SE for music and pass through to a Krell Showcase preamp for movies. Works great for me.

 

I don't think my Pioneer SC LX-76 A/V receiver digitizes input signals when Pure Direct is on, just a clean analog path and amplification, no room correction, no bass management, no sellectable digital filters, nothing more than volume control and source sellection.

 

Same here with my 6-channel Onkyo, it has built in DACs but I'm pretty sure the phono input is all analog, it sounds it.

 

If the AVR includes good room correction DSP and the listening room acoustics cause a lot of imbalances to the frequency response of speakers, then AD conversion shouldn't be worried about. That's because the DSP is worth the extra AD/DA-conversion chain because balanced frequency response sounds much better than imbalanced one. Also if one uses subwoofer to enhance and balance the bass response (AVRs use DSP high & low-pass filters) then the AD/DA is justified too.

Most of the DSPs (at least found in consumer electronics) function at fixed sample rate. That means that all the other sample rates are re-sampled (down or up) to that specific sample rate. Also if the AVR has digital volume control there is a possibility to loose bits from the incoming digital signal. Inner-processing usually though operates in high bit depths so that's not usually an issue. But just to remind that the complete digital signal chain isn't always so trouble-free either.

 

If I was not certain that my AVR was keeping my phono signal in an all analog domain, I could never trust it for needle dropping LPs.

It is a question I've previously thought about. And there must be a way to test the output signal. Perhaps an oscilloscope can reveal this?

 

Beware, an A/V receiver can digitize even the phono input, my Pioneer can do it. With ALL modes engaged included DIRECT it digitizes all analog, including Phono, inputs, it's with PURE DIRECT when it DOESN'T digitaze inputs, as as I said before, no room correction, no bass management, no digital filters sellectable, all this can be done with DIRECT mode, but not with PURE DIRECT, which briefly shows the input source on screen and the displays ANALOG DIRECT. When on any of the "directs" modes on your receiver, check for the one while playing music (better if bass heavy) that MUTES your subwoofer.

 

What if your AVR has a digital output for recording that you use for your needle drops? If it does very high quality A-D conversion then you can plug that into any recording device or computer and get great quality needle drops.