Passive Vs. Active Linestage?

Re: Passive Vs. Active Linestage?, posted on March 17, 1999 at 10:40:58
Jack G	Its a personal choice. Some poeple swear by passives, others do not. I've used them in the past, and they are very transparent, but not as musical IMO as a good active pre. Sometimes you loose dynamics and fullness with passives. I assume your CDP doesn't have a volume control? Jack

Re: Passive Vs. Active Linestage?, posted on March 17, 1999 at 10:43:23

DAVID

This will depend on your amp. Amps that are a good match with passives should have a high input impedance (75k and up), good voltage gain (maybe 28db and up), and a fairly low needed input voltage to drive it to full output. As an example, my McCormack has 100k of input impedance, like 31db of gain and only needs 1v of input to drive it to its rated 180w of output. Most CD player output 2v.
Soundwise, my former pre. was the Audio Research LS-7. Great pre. but compared to the Halcyon passive I went to it had a more restricted soundstage and had a decisive added hardness to the mids and treble. I never actually noticed this 'til I directly compared it to the Halcyon.
I hope this helps.

Re: Passive Vs. Active Linestage?, posted on March 17, 1999 at 10:51:10

J.P.

At this moment I have taken home a used Precision Line Interface Model 2000 passive preamp. I made inquiry about this preamp on this website, so far I got no responce, thus assuming nobody knows anything about them. I have just begun aditioning it before I decide to buy it. I have taken the cover off for inspection, -to discover there was almost nothing inside. There was the output, four inputs which were wired directly to the front panel with four input switches, and one volumn pot with the label "PENNY+GILES STUDIO EQUIPMENT" made in the UK, batch no. 10-90. There was also a ground wire soulderd to the cover plate. All wireing appeared to be silver wire. People who talk about passive preamps mention Vishay resistors, -I didn't notice any resistors in this unit. At the bottem of the chassis there apeared to be a pc board, but there didn't appear to be anything on it.
I have auditioned it briefly and can give you only a first impression. There was a slight clarity in the CD performance, -maybe the highend was a little too bright and etched.
I played it through my new Rega 25/RB-600/Clearaudio Aurum beta S mm. cart. and AcousTech PH-1 phono-stage, -IT WAS WONDERFULL !!! Talk about transparency, detail, immediacy, and space, -this had it!!!.
Now to your question, if this passive preamp is a typical example, and if your going to play only CD's, perhaps an active preamp is best for you. On the other hand if you are playing LP's, a passive unit can be wonderful.
I still would like to know if anyone has ever heard of or used a Precision Line Interface Model 2000 passive preamp,and how they stack up against other passive units. I was told the new price was about $1000.00. I would be gettting if for about $350.00

The good news is......, posted on March 17, 1999 at 11:32:11

Dave B

The P&G potentiometer is one of the most costly. It is so good, that it can be used in video control mixers and used to do fade in & out without loss of signal(video quality). This is impressive. It also should have a very nice feel to it. What did you expect to be in a passive pre?? Think: Less is Better. Be glad that the designer chose to use that pot and hopefully the wire and connectors are as top notch as the pot.

Re: Passive Vs. Active Linestage?, posted on March 17, 1999 at 16:34:47
Tazsmonn	I'm using 2, a QED & an ADCOM.There both lower priced models. sounds better than any preamp I've had !

Yes but....., posted on March 17, 1999 at 16:46:01
Bryan F.	....an attenuator using resistor's like the expensive Vishay or even the more affordable Holco will out perform even the mighty Penny and Gills potentiometers. Especially if it is a L-pad(Ladder type attenuator). As this is truly the simpliest of volume controls.

One more thing...., posted on March 17, 1999 at 16:50:05
Bryan F.	....a passive will usually beat an active in terms of transperancy, detail, and openness amongst other things against an active below about $2800-3000. However after this actives usually begin to come to life. Though some will still prefer a passive. However this just goes to prove that a good active does cost mucho bucks.

What about buffered?, posted on March 17, 1999 at 16:51:05
Bryan F.	Hey, you might as well consider all three forms of linestages....

Re: One more thing...., posted on March 17, 1999 at 18:27:43

DAVID

Yeah, that's why I stick to buying used products these days. Also, with all the talk of how to improve a particular systems sound I found that, by far, the biggest change/improvement in my systems sound came when I replaced a $350 Carver preamp with the Audio Research. All the other changes: amp, speakers cables etc. did not change the sound nearly as much as going from a cheap pre to a fairly good one. I would love to hear one of the really good and expensive ones!

Re: Passive Vs. Active Linestage?, posted on March 17, 1999 at 18:53:18

Hyperion

It depends on your power amp, your cabling, your priorities and your budget.

First, is your power amp receptive to passive drive? It has to have high input impedance (preferably 100Kohms) and medium to high gain (25 dB or more). The cable should not sound bright or lean as this will tend to exacerbate the slight loss of fullness with passives.

Do you really like the sound of your cd player? Does it sound warm or full enough? Is it dynamically wimpy? Does it have deficiencies that you think must be compensated for by an active pre? Are you a soundstaging freak? How much is your budget? Tubed active preamps can sound transparent but usually only after a certain price point. Affordable transparent active preamps are as rare as hen's teeth. (and I have a funny feeling that the elusive beast must have a tubed psu, and short path hardwired components to achieve transparency hehehe)

As a dyed-in-the-wool passive line stage attenuator user for 5 years, I recently took home 4 preamps. (CJ PFR, PF2, Premier 14 and ARC LS15) Initially all of em sound tonally okay, all the CJs sound warm and golden as expected, although the two ss preamps had traces of grit and grain in the treble. The LS15 sounded sweet and delicate (surprising for an ARC product!). However, let me cut to the point. I was utterly disappointed by how noisy these units are. Music seems to emerging from a layer of grunge instead of silence, as if the sonically deleterious grills of my speakers were suddenly in place even though they were not! The ambiance and all important microdynamic nuances all got buried under the noisefloor ... Music seems generic, with limited tonal colors and shading with these preamps (most notable with the ARC unit). All these actives provided a meatier (but less extended bass, probably due to finite capacitor coupling) and more defined (albeit less tuneful) bass. The actives also has better dynamic peaks (no surprise there) but worse dynamic contrasts. The dynamic shading appear to be very coarse making music sound mechanical in nature - this especially true for the 2 ss preamps.

I don't think so but....., posted on March 17, 1999 at 19:00:39

Dave B

give me your rationale, anyway.

This will be interesting.

Re: I don't think so but....., posted on March 17, 1999 at 22:27:44

Bryan F.

First of all an L-pad means expensive construction. Usually an L-Pad starts at around $250 per stereo pair with Holco and can reach as high as $2200 w/all Vishays(yes for two tiny attenuators). The biggest plus is that one resistor is in the signal path at all times. As you step up or step down attenuation a single resistor resides in each spot. Thus only one resistor is in the signal path. Not all as with a series attenuator. Where as the whole potentiometer is in the signal path. However the biggest advantage is not only the use of high quility resistors resulting in a better overall sound but is that it is able to achieve a constant input impedance and only the output impedance varies(of course). Potentiometers don't have a constant input impedance to my knowledge. It is simply the best choice where a constant load is desired. Being that the unit is passive one needs a constant input impedance.

Of course you could always try an L-pad. As if you think a P&G potentiometer is the best replace them with a stepped attenuator(s). Though L-Pads have drawbacks. In that they don't offer remote control and if you are using a pair of them you have to change volume with on both. Though a few companies have designed dual mono volume controls. Though they lack remote. Only Placette offers a remote to my knowledge but he does it a different way that I am unsure of. As he doesn't use attenuators to my knowledge. Remember that a volume knob does have a huge sonic impact on the final sound.

Second Day of Auditioning, posted on March 17, 1999 at 22:34:02

J.P.

This is the second day of auditioning the Precision Line Interface. The first day I was somewhat reserved about CD's on this passive preamp. Today I tried Cassandra Wilson on Blue Note CD's, wow!! -She was right in front of me in person. I've come to the conclusion that if your going to have a passive preamp, boy, you had better have first class recordings because their going to reveal all the glory or all the grundge. "The Emporer Has No Clothes!!!"

Re: Balanced Line Stages etc., posted on March 18, 1999 at 00:01:49

Steve

>>I was utterly disappointed by how noisy these units are. Music seems to emerge from a layer of grunge instead of silence, as if the sonically deleterious grills of my speakers were suddenly in place even though they
were not! The ambiance and all important microdynamic nuances all got buried under the noisefloor ... Music seems generic,
with limited tonal colors and shading with these preamps (most notable with the ARC unit)<<

Exactly! and the raison d'etre for a well designed balanced linestage. The differences are subtle but mega important. Most people however would not hear the ARC pre for example as noisy, but compared to a highly transparent passive, many SE active line stages mask a part of the signal which gives music its colour, vibrancy and life. A lot of the noise you heard is introduced by the mains. A high quality balanced PLC like Equi=Tech will remove a considerable amount of the hash. Ensuring that the linestage is fully isolated from its surroundings (on a Seismic Sink Stand for example) and very well supported to reduce chassis vibration goes a long way to remove the rest (though not all).

BTW, I'm going to be visiting Singapore from 11th to 15th April and maybe able to break free from meetings etc. Any chance of getting together? Maybe we could go audition some AH's if they've arrived!!

Let me know

Rebuttal....., posted on March 18, 1999 at 11:46:59

Dave B

Bryan,

I'll give you my perspective on this issue.

>>$250 per stereo pair with Holco and can reach as high as $2200 w/all Vishays(yes for two tiny attenuators)<< this is ludicrous, I mean we are talking metal film resistors here, either tin or antimony oxides, there is no logical reason these should be so expensive. Even Vishay/Dale metal films are not expensive, in reasonable quantities, probably 1 cent a piece for 1%'ers.

>>It is simply the best choice where a constant load is desired. Being that the unit is passive one needs a constant input impedance<< I don't believe this is relevant or correct for typical home use. Only if you were driving several amplifiers simultaneously from the passive pre would an L pad be an advantage to prevent interaction.

>>The biggest plus is that one resistor is in the signal path at all times<< This is true for the pot but I think you'll find that it's more than one resistor for any given setting in the Ladder Network.

>>As you step up or step down attenuation a single resistor resides in each spot<< again, not true...I think if you research this, you'll find that it is a 'network' of resistors in the path(meaning 2 or more) and you are ignoring the switch contacts in your reasoning for the L pad. The P&G pot is one continuous resistive film with the position being user adjustable and a very high quality wiper contact. This results in many fewer solder joints, discrete resistors and a pair of switch contacts. This doesn't even address the fixed steps in the L pads settings whereas a pot is totally variable.

Finally, my point to the original poster was that the P&G is world renowned for it's quality and lack of impact to the signal it is processing. The fact that the designer chose the P&G is a good sign. L-Pads are useful for certain things, they are not necessarily better than a good potentiometer.

I'd like to think that it is obvious now, that under reasonable conditions, one implementation is not better than the other and that the choice of a good pot is merely a good thing.

Re: Rebuttal....., posted on March 18, 1999 at 14:15:33
J.P.	I would like to thank everybody with this discussion. I ended up buying it, after the comments on this website, and my auditions. Since it was used, it cost me only $300.00 in the end, so what could I loose. I think it will be a very good passive preamp with silver wireing and the famous P+G potentiometer. Again thank you, I think it was a real find !!

Re: Rebuttal....., posted on March 18, 1999 at 14:24:36

Bryan F.

P&G are awesome potentiometers....I'll agree to this. The ease of use also makes them more attractive. They are not the best period though.

Price is justified. As Vishays are build differently using high quility materials to exacting tolerences. If you can find a blown up view of a Vishay cut away diagram and note several things that set them apart from the rest of the rat pack.

Also price is justified because if you used say a Shallco rotary switch you would need 92(184 a pair) resistors per switch. Ummm...that gets expensive. But the Shallco's have 47 steps. You could save money by using Holco's in the lower and higher positions and Vishays in the positions used most. As most people only use a few steps. Also you could cut cost by using a 24 step Elma.

>>>again, not true...I think if you research this,
you'll find that it is a 'network' of resistors in the path(meaning 2 or more)<<<

Yes a "network" is correct. I think of it as one big resistor. Actually I will be politically correct and say few resistors depending on the step. Read below for more info. on this.

I have done my research. As a LADDER PAD or L-PAD features a switchable series and shunt resistor for each position so the audio signal passes through only a SINGLE series element no matter how many db of attenuation. This is the type I am referring to.

Now a SERIES ATTENUATOR works differently. In that with each step UP of attenuation another resistor is added to the signal path. So yes there are a network of resistors in the signal path in a SERIES ATTENUATOR. However I didn't refer to a SERIES ATTENUATOR.

>>>and you are ignoring the switch contacts in your reasoning for the L pad<<<

Nope, I'm not ignoring them. As in a L-Pad only one is in the signal path. If you are using say a Shallco the contacts are solid silver. If using an Elma the contacts are 10um silver coated. If using a GrayHill the contacts are Silver/Gold plated.

In the end P&G potentiometers are the best pots. They also are better than cheaper attenuators. They also are more flexible in use. However any of the above attenuators will sound better than the P&G IMHO and in a lot of others peoples opinions also. If you can live with an attenuator try them and hear for yourself. I wish I was wrong as P&G's offer more flexibility.

J.P., posted on March 18, 1999 at 14:28:26
Bryan F.	Please realize that for $300 you can't go wrong and you got a deal. We are argueing attenuators and potentiometers in general...well high quility ones at least! Happy Listening!

different route, posted on March 18, 1999 at 15:34:06

Dave B

>>If you can live with an attenuator try them and hear for yourself. I wish I was wrong as P&G's offer more flexibility<<

personally, none of them are as good as no analog preamp, IMHO.

I chose the Z-Systems rdp-1 and use it's digital volume control implementation between my xport and dac. The dac is very high quality and drive balanced cables to my m/b's. The auditioning I did between some $5k-10k pre's and the rdp-1 was no contest, plus I got eq to boot. All the pre's I listened to sounded veiled by comparison, so, for the sound I was looking for the choice was a no-brainer. To each, his own.

Z-Systems

Re: different route, posted on March 18, 1999 at 16:03:54
Bryan F.	Hmmmmmm...nice piece but I prefer tubed stuff. Though my speakers use an active eq so..........who cares as long as it sounds good. Thanks for the little war. HEEHEEHEE it was fun to spin off the original post.

final thoughts, posted on March 18, 1999 at 18:50:14

Dave B

There is nothing wrong with spirited debate, as long as the focus is on the issue and not the individual. In fact, this forum would be BORING if everybody agreed on everything.

Preferences are individual and as long as the choices are well thought out and the end result is pleasing to that individual, thats all that matters. It's okay for us to not agree on preferences. This hobby is non-absolute...and some people don't understand this.

Signal path, posted on March 18, 1999 at 23:19:54

Werner

The only true signal path is the one that contributes
to transforming the input signal into the output signal.

In the simple case of an attenuator this always comprises
of the series AND the shunt resistors, all contacts,
all ground tracks, ...

Perceiving the series elements only as the signal path
is wrong.

Visions in Audio

Werner, you monster! That's beautiful! (nt), posted on March 19, 1999 at 05:00:04
dy/dx	ooooohh, baby! But please, turn the record over now.

Werner...., posted on March 19, 1999 at 05:12:13

Bryan F.

You know it is impossible to please everyone in wording everything in a politically correct manner. I was just trying to state that there is less in the signal path. With contact(pair of course positive and negative as what would the other end of the resistor be connected to if - and + didn't exist) being of high quility and the "series" meaning small or singular. A 47 step Shallco uses 92 resistors. Thus in some positions the series is bigger however small in comparison.

you mean....., posted on March 19, 1999 at 05:17:52

Bryan F.

........there are no absolutes in audio.........but but but it's the ninties man......you mean no a single transducer can recreate exactly what is recorded? Oh, man......you mean everything has a sonic charactor....I agree with you. Though we have far to come the truth (or close to it) is out there if one listens to ones ears and somehow forgets markerting ploys and pride of ownership as their soul shopping tool (s). We were born with the best pair of decision making devices invented and audio is designed around them. Happy Listening.

Re: you mean....., posted on March 19, 1999 at 07:00:06

Dave B

>>Though we have far to come the truth (or close to it) is out there if one listens to ones ears<<

The truth is in each and every one of our pointy little heads and it is sure to be different, more often, than it is the same. Again, personal preference. As long as ones choices are well thought out and have an intended purpose and achieve a desired goal. It's a beautiful thing.

IF YOUR GOING TO PROMOTE IT......, posted on March 19, 1999 at 08:47:38
WHAT IS IT'S PRICE ????	nt

$1995 for a MKIII, posted on March 19, 1999 at 10:55:09

Bryan F.

I am considering the GyroDec as we speak. It retails for $1995 with dustcover and base and no tone arm and the Gyro SE retails for $1595 which is the same table and platter as the GyroDec only it has no dustcover and base(of course no tone arm also) saving you a little cash! Below is a link to J.A. Mitchell...just click the link and on the left side click J.A. Mitchell.

J.A. Mitchell Eng.

Or $4200 for the....., posted on March 19, 1999 at 10:58:58
Bryan F.	...Orbe which Werner has pictured. I just took a second look. I thought it was his GyroDec in the picture then realized it was black and had an awwww so thick platter!

Just my point!(nt), posted on March 19, 1999 at 11:00:33
Bryan F.	!

Re: The good news is......, posted on March 21, 1999 at 08:35:30

Mike

Does P&G make a moterized volume pot? Does anyone know of a retail source for P&G parts in the US?

Thanks.

Latest Audition of the Precision Line Passive Preamp, posted on March 21, 1999 at 17:24:08

J.P.

Last night I put on "Stereophile Test CD -3". I turned out the lights and listened to the track where the guy walks around a church santuary, banging on a kettle with a spoon, explaining where he is located in the santuary, -excellent track for determining how good your soundfield is, both width and depth. I was flabbergasted!! When the fellow announce he was in the far right, he wasn't only far right, but far beyond the outer boundries of the right speaker an into the next room. You could actually hear him crisscross the the santuary and go behind your back, without rear speakers even. This was with a VTL Renasance 70 amp on Spendor SP-100's.
Previously I had a VTL maxline pre. but it was never like this.
Does this mean that active preamps restrict the capabilities of the amp., since passive pre's aren't suppose to do anything eccept get out of the way, and that the amp is actually doing what it is capable of doing??
Actually I had auditioned a small McCormick passive preamp., I didn't like it because I felt the sound field was bunched up and ennimec, although transparent and detailed, -it was nothing like this.
I am still interested in knowing if Precision Line makes other products, because if they do, it's well worthwhile checking them out.

General Asylum

Passive Vs. Active Linestage?

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