[batmanslc2]

I've had a few, this one in particular   FT audio LW

http://www.soundstage.com/revequip/ftaudio_lw1.htm

For the price it did a lot of things well, in the end the music has more "life" or aliveness with a good active design.
I would also like to try a  sonic euphoria, have read some very positive things....

[Quiet Earth]

I really enjoy my passive transformer volume control from diyhifisupply.  My power amplifiers have a lot of gain (250mV sensitivity) and my speakers are more efficient than average (greater than 95dB). That combination of high gain and high efficiency is the main reason to consider going with a passive pre.

I understand the "no meat on the bone" comment about passives because I had that experience the first time that I tried one. Yes, I heard all of the detail unleashed by removing the gain stage of my active pre amp, but I also lost all of the drive that it provided. At that time I didn't have a sensitive power amplifier or sensitive speakers. It was a poor solution for that system.

As for keeping a low source impedance and short cables, that guideline applies to using active pre amps too. All preamplifiers use a passive volume control. There's no practical way of getting around it.

[drphoto]

Someone here is selling a Sonic Euphoria for a very good price. Maybe gone by now. A trusted source (someone who is a very critical listener and know his stuff) raves over it. He says it is incredibly transparent but does not stuffer form some of the problems of other passive designs. (lack of dynamics at low volume, cable issues, etc)

Me? i've not heard it, but if I had a loose dollar to spend, I'd give it  try, based on the recommendation.

[Big Red Machine]

Someone here is selling a Sonic Euphoria for a very good price. Maybe gone by now. A trusted source (someone who is a very critical listener and know his stuff) raves over it. He says it is incredibly transparent but does not stuffer form some of the problems of other passive designs. (lack of dynamics at low volume, cable issues, etc)

Me? i've not heard it, but if I had a loose dollar to spend, I'd give it  try, based on the recommendation.

I owned one about 3 years ago.  It really didn't float my boat, neither did the Promethius I tried about that time.  Then I went active for years and wanted to know if any developments in passive topologies are worth investigating now.

[Mike Nomad]

I was a passive-pre user for years. I've got three in the house (Channel Islands VPC-1, Monolithic PA-1, and a Yamaha MVS-1). I'm using the Yamaha in a bedroom system because that's the one I don't have the box for.

+1 to the idea that impedance matching is critical.

The CI was the most forgiving across a number of different amps. The Monolithic stomps the CI, but only when it is paired with the "right" amp. The Yamaha is somewhat finicky, but it has a set of 5.1 I/O...

I was looking for simplicity (and a remote) and an amp with more grunt. So, I went integrated and got a Peachtree Nova. I don't regret the move at all.

[turkey]

I've tried both resistive and transfomer volume controls. The resistive ones tended to roll off the highs, and they never sounded as good as a regular preamp.

The TVC was attractive because it was dead quiet. However, it also never sounded quite right. (It was like it sucked all the dynamics out of the music.)

I'll stick with my preamp, thank you very much.

[earplay]

Sorry if this has been mentioned, but Nelson Pass' version of a passive pre was very positively reviewed recently by Enjoy the Music. The reviewer kept the review unit.

It sells for $1000 according to Enjoy the Music, but you can buy a kit for about $50 on eBay.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=320484651290&Category=3280&_trkparms=algo%3DLVI%26its%3DI%26otn%3D1

And if anyone knows how to insert a link into a word in the text, please PM me with the details.

[Jon L]

Sorry if this has been mentioned, but Nelson Pass' version of a passive pre was very positively reviewed recently by Enjoy the Music. The reviewer kept the review unit.

It sells for $1000 according to Enjoy the Music, but you can buy a kit for about $50 on eBay.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=320484651290&Category=3280&_trkparms=algo%3DLVI%26its%3DI%26otn%3D1

Thanks for the link.  Looks like it only requires 18V DC, meaning one could rig up something off power tools' 18V batteries

On the other hand, I didn't realize B-1 goes through 10uF coupling capacitors.  I'm not sure I want to subject my signal to 10uF capacitors, however "good."

[ctviggen]

Another possible way to improve the sound when using a SB is to get a buffer.  Whether you go with Wayne at Bolder or Gary at Dodd, I am confident that inserting one of these into the chain will make an improvement.

Only problem with the Dodd buffer is that it has no gain.  I went from using a Proceed preamp with my modded SB to using the SB directly into the amp.  The SB lost a lot, most of all volume.  Even full blast, the SB couldn't drive the amp high enough.  It also lost quite a bit of dynamics and liveliness.  The Dodd might get you the dynamics and liveliness, but it won't get the gain.

I bought a Dodd battery Pre instead of the buffer.  They were about the same price (the pre was used; the buffer new), but I needed the gain and also wanted HT bypass.

[Danny Richie]

I have tried a good handful of passive pre-amps over the years and most were lifeless, flat, and dead sounding as they relied on the drive and power supply of the source.

Two were different.

One was the Superphon. It had an active buffer stage.

The other was the Dodd Audio passive with tube buffer.

I guess there is a lot to be said for the impedance matching of the buffer system.

The Dodd is still in my system.

[DaveC113]

I've tried my system with and without preamps, and agree active is the way to go. I had an adcom 750, and now have an Anthem Pre1 6922 tube preamp. Both were good, but the Anthem improves the tone and soundstage to a greater degree. The preamp was a much more dramatic improvement driving a digital amp than my current el34 SET.

[konut]

I guess there is a lot to be said for the impedance matching of the buffer system.

 

This is the key to getting a passive to work correctly, buffer or not. Low capacitance, short, cables, source with extremely low output impedance, and amp with high gain and high input impedance. Otherwise, use an active.

[Ric Schultz]

Yes, using a passive can suck the life out of a system unless you:

1. Mount it at or inside the amp and you pay attention to make sure you have a low enough impedance source to drive it and enough source voltage to play as loud as you need.  I have used a shunt attenuator inside my amp for years and nothing can touch it.  Just a nude 10K Vishay series resistor and then I have a switch that switches resistors to ground.  All the bass and dynamics you could ask for (driving from low impedance solid state source).  I used to sell my Ultimate Attenuators in reverse, so they could mount on the source........but as soon as you put it on the send end of the cable then you lose bass, dynamics and transparency.  You really need it right at the load.  So, inside the amp rules.

2.  Use a great TVC....these things can have low output impedance.  A friend uses the the Audio-consulting Silver Rock and he shakes the house.

[NewBuyer]

...I used to sell my Ultimate Attenuators in reverse, so they could mount on the source........but as soon as you put it on the send end of the cable then you lose bass, dynamics and transparency.  You really need it right at the load.  So, inside the amp rules...

Is there an advantage to putting the stepped attenuators inside the amp, versus putting them directly onto the amp's input and trusting the short remaining signal path (e.g. operating like Scott Endler's Shotgun Attenuators do?  I have had terrific results with those Shotguns...

[TRADERXFAN]

I owned one about 3 years ago.  It really didn't float my boat, neither did the Promethius I tried about that time.  Then I went active for years and wanted to know if any developments in passive topologies are worth investigating now.

I have heard a sonic euphoria as well... and it was quite impressive. However, sometimes it doesn't agree with certain components. So its a bit of a crapshoot. Some will find nirvana, and others will be dissapointed.  I have the Dodd buffer, but I had considered buying this used one that was mentioned for a bit.  With the sub amps the buffer is probably better suited for my needs.

[roymail]

Guys, passives don't sound like anything!  Good ones allow you to hear what the source, source recording and amp are delivering to your speakers... and no more!  Synergy plays a significant roll as it always does.  Personal preference plays a big roll as it always does.  System matching plays a big roll as it always does.

This is what I did to convinced me that *I* (notice I didn't say you) wanted a passive in my modest single source system.

My modded cdp is my single source and outputs 1.75 volts.  I plugged it directly into the amp.  I put on some well recorded jazz (piano, bass and vocal) that wasn't too loud or rowdy.  What I heard was simply the best sound I'd ever heard from my system in my house. 

So I constructed a simple diy passive using a 20K stepped attenuator to see if I could get the same sound using this simple volume control.

The amp has 47K input impedance, source output is 1.75 volts, used short low cap cables (1.5').  The result had plenty of volume, dynamics (contrary to what some others have experienced) with my 91db speakers and is neutral and revealing.  Of course it's very source dependant.  Excellent recordings sound wonderful while I can't listen to many poor recordings.

I'll say it again... passives don't sound like anything!  Good ones allow you to hear what the source, source recording and amp are delivering to your speakers.

I'm convinced that many like their sound "warmed up" or whatever.  You may want to consider that amps can also have an effect on what you hear.  I know that tube preamps can "flavor the sound" hence... "tube rolling."

This is just my experience.  I like things clean and simple. 

[Niteshade]

Passives work well with Tripath and Class D amplifiers that have allot of gain. I like actives on linear solid state amps and tube amps work well with either, as long as their gain permits it.

[shep]

Might as well add my 2 cnts. I have an ice amp integrated with a very nice resistor pot. Cullens did a great mod for me, putting their buffer stage behind it. I guess I have the best of both worlds and certainly hear nothing of the negatives mentioned.

[ctviggen]

I have tried a good handful of passive pre-amps over the years and most were lifeless, flat, and dead sounding as they relied on the drive and power supply of the source.

Two were different.

One was the Superphon. It had an active buffer stage.

The other was the Dodd Audio passive with tube buffer.

I guess there is a lot to be said for the impedance matching of the buffer system.

The Dodd is still in my system.

In my mind, a device with a tube buffer isn't a "passive" device.  A passive simply selects between signals and does nothing else.  A tube device, even with no gain, is still really an amplifier with no gain. 

[Danny Richie]

In my mind, a device with a tube buffer isn't a "passive" device.  A passive simply selects between signals and does nothing else.  A tube device, even with no gain, is still really an amplifier with no gain. 

Nope, it's an impedance matching device with no gain. And the performance difference between it and a stepped attenuator is very significant.