interesting audio thread......

TroyD

OK, here we go......

BACK to the passive preamp thing......

Russ and I did some fairly extensive demo's of the ADCOM SLC-505 this past weekend using a Carver m400a cube amp, various speaks (big ol' Sansuis, Polk, B&W bookshelves), old ADC CD player, good interconnects and basic lampchord wire.

I think that we both agree that a passive preamp lives up to what we, or at least I, thought that it would. It adds nothing. It detracts nothing. I feel that it eliminates extraneous (good or bad) coloration and gets you closer to the original intent of the recording.

If your sources suck, the passive preamp will make this fairly obvious. It won't put a happy face on it for you.

OK guys, here is your chance to chime in with your thoughts and comments and have an interesting audio thread.


Big Dumb Troy.....

RuSsMaN

I agree a passive is the way to go. Sonically it does not add/color at all..... (I also thought we were gonna keep this on the down low until I could find one dumbass )

Question I pose is this, why would one want an active pre? What does it bring to the table? (other than maybe a built in phono-stage)

Not personal preference, ie : 'I like the way my McIntosh pre sounds', but more from a music purity standpoint....your source, your amp, your speakers- as little possibility of coloration as possible.....

I notice some high end Wadia and Krell basically have a similar setup, by having a cd/transport/dac WITH volume control.

Cheers,
Russ

mantis

sound's like a good time.Preamp's do different thing's to your sound, but at the end of the day,you really don't want any change at all.Sometime change is good like when you use a Audio Research Tube preamp and makes you sound warmer, and more dynamic.Preamps also are at the mercey of the interconnect.Balanced or not.Then the gain issue if the preamp can drive the amp to disired level's without distorting.
Does the given speaker's sound really good with this setup?What about speaker wire?Can it keep up with the amp that feed's it?Is the source matched correctly with the rest of the system???????
TEST TEST TEST TEST.........then enjoy for a while then TEST TEST TEST..........LIKE A MADMAN.

TroyD

Man, sorry about that Russ, however I doubt that there is going to be a mad rush for a passive preamp......

Again, this is the way I look at it..........I want to hear the intent of the original recording with as little extraneous coloration as possible. Coloration is just another term for distortion.

Again, my thought is, if your amp, speaks, cables, source etc.....suck, it shouldn't be up to the preamp to hide it. Which I wonder just how much a regular pre could do anyway.

We did, what 12 hrs give or take demo time with pretty common gear and I think the results are outstanding....

C'mon guys, step up, you want an interesting debate, well here you go.

Big Dumb Troy

rskarvan

Ok... shoot me.
I bought a krell kav250a. 250wpc clean sound.
I ran it from my Denon 3801.
The sound was relatively clean; but, my goal is to someday
obtain a quality two channel rig.
So, one day, I found the krell kav250p preamp.
I splurged and bought it.
The krell preamp is both a resistive network (passive)
preamp AND also has an active portion.
The reason that I bought the matching krell preamp
was so the electronics in the preamp would exactly MATCH
the electronics in the amp.

You need some activeness in the preamp if you are going
to drive the source LOUD. Anyway, both are balanced and I've
read that krell balanced is much better than running unbalanced.

Now, the results....
The krell preamp does NOTHING to the sound.
It doesn't change it - at all.
The Denon3801 as a preamp was alright... but, it colored
the sound of the cd player and added a little (minute) hiss.
The krell preamp - NOTHING. ABSOLUTELY NOTHING.
Buying a high quality preamp is kinda disappointing.
The better the preamp... the LESS NOTICEABLE IT IS.

The krell preamp has a theatre thru-put mode that I use with
the Denon3801 for watching movies. That works fine - nice
feature actually.

My goal, eventually is to dump the SRS SDA 3.1TL's and replace
them with a nice set of USED Thiel 3.6's - I think.
My goal is extreme clarity and accuracy. The polks have reached their limit.

I played around with powering my Monitor10 series 2 with my krell setup. IT ROCKED. I've never heard a monitor 10 sound thump like that. WOW ! ! !

Enough rambling for now. Bye.

TroyD

...I'm just looking for some debate and further explanation here. Certainly not knocking anyones choice of gear or what they like. This subject just fascinates me.

I will flat out disagree that a passive can't drive a system to uncomfortable listening levels. Heard it with my own two ears. But how do you KNOW that the active pre adds nothing? Assuming that is true, essentially then, the way I look at it, if the active and passive portions sound EXACTLY the same, why have both? Other than for a phono stage.

The whole balance thing, that I don't know about.

I agree with the statement that the better a preamp is, the less it adds to the sound. Which begs the original question why not just have a passive pre. Simpler and cheaper.

I'm not trying to bust anyones chops here but I have GOT to be missing something.

Big Dumb Troy

madmax

Some times you need gain. That is the original reasoning for a pre-amp. I think it depends on the rest of your system. At one point I started using an active pre-amp because the sound was very dull. Once I upgraded a bit the active only colored the sound. I guess the new CD player had a higher output or the new amp required less input. Or both. In any case if you go totally passive and build around it you will have a cleaner signal path. My last set of Jolida's are integrated amplifiers and I think I like it that way for the tube stuff. At least so far. All of the components are wired close together and you don't have to worry whether an interconnect is messing with you. Of course you end up with the same supply driving both section so who knows... Test, listen, test, test, change, listen. It never ends.
madmax

TroyD

....just to add.....if anyone has or knows where there is a passive preamp to be had, reasonable price, let me know. I'll suck it up just to keep Russ jealous.

BDT

RuSsMaN

I do recall that when we were running the Carver m400a with the B&W601's, that the 'gain' (or lack thereof) knob on the Adcom passive pre, was turned 'up' fairly high.

Actually, most of the time we had it half-way or better. If that little cube is 201wpc rms capable, and the 601's are 125wrms capable....we should have been near the breaking point on them, yet they didn't budge. And short of the William Tell Overture, we didn't even see the Carver light up much.....

Man, what I am trying to say is it seemed like we had the pre turned up noticeably more than I intially thought we would have.

Going back to what Skarvan said, maybe that is a '+' to having an active pre..... Perhaps it has better ability to drive the amp, if that makes sense.

Cheers,
Russ

TroyD

.....didn't it seem though that it was very dependent on the recording?? Maybe I was just hammered. I dunno.

I know for a fact though, that we were never close to pulling anywhere near that kind of juice from the carver though.....I need some edu-ma-cation on all this.

I should have the rig all fired up this afternoon. I'll report my findings.

BDT

wangotango68

look at your car stereo head units alot of them boast about
having 2,3 and 4 volts output on the preamp side.


scott:cool:

Aaron

I don't have any experience with passive pre's, but I could see cases where you'd need the gain. If you have really inefficient speakers and a source component with a low output, you might need it. When you brought this topic up the first time, someone said that an active pre helps to impedence match components. It seems like an active pre will work with a wider range of components. Like I said before, if you're horny for a passive pre, check out the Adcom GFP-750. You get both an active and passive preamp in one box that changes with the flip of the switch. At $1500 it's not exactly cheap, but it's not terribly expensive either, especially for a Stereophile Class A component (cheapest pre by far to receive the Class A rating).

Aaron

TroyD

I been thinking about the speaker efficiency thing all morning to be honest.....that may definately be a cogent point. Seeing that the DQ-10's are about as inefficient as speakers get. When we hooked up the Sansui's (very efficient) as opposed to the B&W's it seemed that the knob didn't need to be turned up nearly as much.....

I've already got a passive pre (Adcom SLC-505) so I am not looking for one. Although I think Russ might be.

Anyway.....good stuff here guys, keep it flowing. Also, please don't think that I am knocking the active pre's you guys have, just looking to educate myself.

Big DUMB Troy