Revised preamp wish list...

Rob Babcock · « **on:** 27 Jul 2003, 10:07 pm »

Well, just thinking/dreaming a little more about the "perfect" multichannel preamp. My thinking is that it would be basically like a Sabai, but where the Sabai has a 2 Ch HT passthru, my dream preamp would have one 5.1 Ch HT passthru and one 5.1 channel line level preamp input. Additionally I'd like to see at least three or four stereo input too. No video switching would be necessary.

My thinking is that those of us with HT Recievers/Pre Pros that we're happy with could run those into the HT Passthru and use it that way for movies and regular TV sources, with a nice Hi Res source (like a universal player) connected to the line level 5.1 input. Add inputs for a CD player, a record loop, and an aux for those that use those funny looking big black platter thingies

and you'd be all set!

This would pretty much let the full glory of MC shine thru while allowing us to keep current on new HT formats by keeping a midpriced receiver with preouts.

I realize adding the ladder resisters to the extra channels would run the price up, but it would allow more precise channel balancing and keep the front face a lot cleaner (less knobs, just buttons for channel balance- and it could be made to work easily with the remote that way).

Well, that's the dream. Any chance something like this could/would actually be produced by IRD?

Preferably soon?

Thanks for listening to my rantings, Curt.

Curt · « **Reply #1 on:** 27 Aug 2003, 04:16 pm »

Hi Rob,

Interesting but not for a while. I'm more into 2ch than multi. That don't mean after I finish what's on my plate I won't look at this again

Now I'm thinking a DAC in a 2ch preamp...

Rob Babcock · « **Reply #2 on:** 27 Aug 2003, 06:50 pm »

Oooh, that sounds pretty cool, too. Anyway, just checking.

jbgcpa · « **Reply #3 on:** 27 Aug 2003, 08:04 pm »

Quote

Now I'm thinking a DAC in a 2ch preamp...

Curt,

Is this DAC project in addition to or instead of a stand-alone DAC that you have made some reference to in the past?

Thanks,
Jack

Curt · « **Reply #4 on:** 27 Aug 2003, 08:23 pm »

Hi Jack,

Nice to hear from you, hope all's well.

Yes, this is the same tube DAC. It could be offered standalone and in a preamp.

Just think one digital input and four analog inputs, choose with the selector switch. I like this idea, what do you think? Still rather have a standalone?

MaxCast · « **Reply #5 on:** 27 Aug 2003, 08:30 pm »

If I buy one of your preamps and like the DAC, I would like it stand alone.

Curt · « **Reply #6 on:** 27 Aug 2003, 09:30 pm »

Max,

Yes, your system is more flexible that way, but it does costs a little more. Probably worth it if you like to change gear a lot like most audiophiles.

jbgcpa · « **Reply #7 on:** 28 Aug 2003, 01:51 pm »

Curt,

Thanks for the quick response. I've been eagerly awaiting the release of the remaining E1 series products.

The notion of having the DAC within the preamp is something I haven't thought about. I had the mind set that I was waiting for my Sabai and then your DAC.

If you don't have to compromise the performance of either component, then combined would be fine. I think you may have told me in the past that the DAC is where the music is - I'm not an engineer or have any technical background, but it has been my experience that a device designed with a single function usually performs the best when it is not integrated into a multi-purpose device.

Perhaps you could begin a thread/survey designed to elicit thoughts of the many knowlegable AC'ers. A retail client once told me, "if the customer likes it - I love it".

Jack

JoshK · « **Reply #8 on:** 28 Aug 2003, 02:03 pm »

I have always thought that adding a DAC and a preamp together would make for the simplest and potentially best performing component do to shortest signal length and lack of extra connections. Of course there are issues involved in supply power to the digital and analog functions and keeping it all seperate. Would the digital and analog section, in your current thinking, have seperate power supplies? That would seemingly rock!

You are right in that it isn't the most flexible for the ever-unsatisfied-audiophile, but for those who just want the easiest and simplest system, this would be it.

Curt · « **Reply #9 on:** 28 Aug 2003, 04:00 pm »

Yes, the digital power supply would be completely seperate.

nathanm · « **Reply #10 on:** 28 Aug 2003, 05:54 pm »

I'd like a circuit that compensated for the fletcher-munson curves for less boring listening at low average in-room SPLs ie 50-60db and also different room ambiences. I don't want to say what this device actually is, because it's a dirty, foul, sinful swear word and should not be spoken or written in polite company. In fact, even hinting at it is grounds for ridicule. I am sorry to have even brought it up...My apologies.

Curt · « **Reply #11 on:** 3 Sep 2003, 06:35 pm »

Loudness control

Want balance and tone controls too?

Actually there is nothing wrong with these devices if their implemented correctly, sometimes they can help out a bad recording or room condition.

That said... it does seem they are a not too popular topic. Anyone else got a comment?

nathanm · « **Reply #12 on:** 1 Oct 2003, 09:04 pm »

Quote

Actually there is nothing wrong with these devices if they're implemented correctly

Wow, could it be?

That DACT balance control (+\- 3db in .25db steps I think) on the 'ol LLC-A would be an extremely useful feature. Precision control is imperative here and since that doohickey's got the stepped resistor magic happening there'll be no heart-wrenching sobs about "icky pots" I would hope.

While I'm at it a Mono switch would be nice too.

What better way to make sure your sound is dead nuts centered, eh?

Rob Babcock · « **Reply #13 on:** 1 Oct 2003, 09:09 pm »

A mono switch be cool. As for the other, I have found it handy to compensate for the Fletcher-Munson Curve by rotating the gain knob clockwise until the sound smooths out and the bass sounds good.

Oh, you mean for times you can't crank it?

Marbles · « **Reply #14 on:** 1 Oct 2003, 09:52 pm »

Quote from: Curt

Loudness control Want balance and tone controls too?

Actually there is nothing wrong with these devices if their implemented correctly, sometimes they can help out a bad recording or room condition.

That said... it does seem they are a not too popular topic. Anyone else got a comment?

Curt,

Did you find a way to implement these correctly?

Curt · « **Reply #15 on:** 2 Oct 2003, 02:50 pm »

Quote from: Marbles

Curt,

Did you find a way to implement these correctly?

Well, now that's a real hot potato

We all know if you don't need these controls it's best not to add them. But, for a poor recording, a listening room problem, or a problem spot in the loudspeakers response (after all nothing is perfect) they may save the day.

You can add these controls, in moderation, offering only subtle changes which won't screw up the music any more than the defect your fixing with them. And you can design in a "defeat" that removes the controls from the signal path when not required.

I haven't used tone controls for a long time, bass boost can be nice for mood music at night, balance can help when the sweetspot needs to be slightly off center for some room placement reason.

I see most of these as issues that might arise in a secondary audio system, not a main reference system. So what does that mean? Add these controls to a preamp? Or perhaps an integrated that will many times be used in secondary systems...

It would be interesting to hear from some people who now use or would like to have tone, loudness, and balance controls.

BTW : Rob what do you use mono for? I like it for testing sometimes but haven't run across that feature in a while either.

Rob Babcock · « **Reply #16 on:** 2 Oct 2003, 02:54 pm »

I don't really use it much. I do of course listen to some mono stuff (eg Beach Boys) but wouldn't need a mono switch. It's handy for testing, and sometimes good for running sine sweeps and test tones when calibrating stuff. I wouldn't need it, but if it didn't add much to the price it would be fun to play with.

Sure would rather have a MC preamp, though, than a stereo one with a mono switch & tone controls...

nathanm · « **Reply #17 on:** 2 Oct 2003, 03:09 pm »

To me it seems as though the point of the "Audiophile" preamp is that it has more features than the "Purist". So I guess if a person feels these type of controls corrupt the sound, that's cool - then buy the Purist. I personally would like the additional controls on a different, more expensive model. I mean, if there's a pink noise function on there for 'diagnostic purposes' it would make sense to also have a balance control or a mono switch etc. Those kinds of things are also diagnostic controls.

In my current system I think the amplifier or CD player has a slight imbalance and I have no way of doing anything about it. A little tweak to the other side is all it would need. When listening to vocal stuff especially you can tell if the voice is not centered.

I know that people get their knickers in a bunch about tone controls, but if they can make transparent, high quality EQs for mastering consoles that we're all listening to anyway, what's to prevent an equally well-done circuit on an end user's preamp? Don't give us too much rope to hang ourselves, but a "tilt" here and there would be great to have. Otherwise we're at the mercy of the recording.

So in my opinion it isn't an issue about 'ruining' audio purity with these controls, (I doubt they would anyway) because IRD already makes a product for that type of customer.

Thump553 · « **Reply #18 on:** 2 Oct 2003, 03:22 pm »

Remote control volume. Its remarkable to me how few decent pieces of equipment have this. Am I the only one who loves to raise or lower the volume level several times during a song? (I already know my wife's thoughts on this matter-it usually involves a rolling of the eyes).

I play a lot of "technically deficient" CDs (amateur recorded concerts) so tone controls aren't a crazy idea to me. But loudness control is the button I switch off after the kids have driven the minivan.

nathanm · « **Reply #19 on:** 2 Oct 2003, 03:33 pm »

Isn't a Loudness control just a preset EQ curve? Does anyone know where one could actually see a graphic plot of what they do?

My NAD 3225PE has the best tone controls I've ever heard. I really feel they do not screw up the sound, they add some sizzle on the top and some warmth in the bass, that's about it. Very subtle.

The truly full-ass thing would be to gang the volume control with a variable-state Fletcher Munson compensator EQ circuit so that there would be no Loudness control, but rather that the EQ boost was married to the gain. You'd have to have a way to calibrate it so that you'd get out your SPL meter and measure 70db or whatever and then set the controls to say, 'okay at THIS position we're getting 70db in the room, so therefore the EQ curve should be set like THIS...' Something like that. So basically after a certain point the EQ boost would be switched out completely and the volume control run straight through.