[Nick Dangerous]

John Curl of Parasound, Inc. is famous for designing equipment that performs admirably yet isn't priced into the stratosphere. The new Halo line from Parasound features this preamp/headphone amp ($795):

Parasound Halo P3 preamp press release page

Yessir, that's XLR balanced input/output, unbalanced input/output, 6 inputs (with phono), remote, headphone jack, ground lift switch, and huge warranty. Plus, it looks really cool.

Gotta try this one!

 

[darkclouds]

Damn Nick,
Haven't we all spent enough money yet?

 

[kelly]

I've read good things about Parasound products in general, but their failure to talk to the headphone section specifically in the press release may be a telling sign that it is an afterthough as it is on must preamps and receivers.

I'm surprised you would opt for a solid state preamp too, Nick.

 

[Nick Dangerous]

The Oris 200 Project uses a passive preamp!

Tubed headphone amps are one thing, but quite another matter if speakers will be the output device. You gotta spend around $2000 (!) to get a decent tubed preamp for a speaker system. Cheap tube preamps usually muddy up the signal rather than enhance it. This effect is less obvious on inexpensive speakers, but with ultrasensitive speakers such as Lowthers or AER's you'll hear it every time.

The best preamp is usually NO preamp.

In most cases it's better to stay passive (or go with a solid state preamp if absolutely required). Tube sweetness can be ideally added later at the amp stage. Some people like to add tube sweetness at the preamp stage, but why complicate the signal with additional electronics if your source already pumps out enough power?

Passive -> Tube amp -> Speaker = Less is more.

Melos SHA-1 is a good case in point. It's a wonderful headphone amp but is only OK as a tube preamp for speakers. A/B the Melos against a passive and hear it for yourself.

 

[kelly]

Nick
I recommend you audition the EAR 834L.

 

[MirandaX]

Quote:

Originally posted by Nick Dangerous The best preamp is usually NO preamp. In most cases it's better to stay passive (or go with a solid state preamp if absolutely required).

Sorry Nick, but got to absolutely disagree with you here. I see this argument all the time; passive is better than active. I think this belief stems from the "if we can eliminate as much as possible from the signal path, it must be good" belief. Scientific minded types (scientists, computer people, etc.) tend to really gravitate towards this belief, IMHO, because it seems wonderfully pure. But once you think about it logically, it's false. Without an active preamp, you're making your power amp work many, many times harder. You need a dramatically better power amp to compensate for this, one that's many times more expensive than a good preamp. A low-powered triode tube power amp cannot handle this job. Think about it:
case 1:
passive preamp gain: 0 db
amp gain required to get 80db of loudness: 80db

case 2:
active preamp gain: 20 db
amp gain required: 60 db

That extra 20 db in the first case means your power amp needs to work more than six times harder! Unless you have a wildly powerful solid state power amp, do yourself a favor and try an active preamp.

Most people dislike active preamps because they "deaden" the sound. If you feel this way (I absolutely do; it's because solid state designs typically have up to 70db of negative feedback), go for a tube design with zero (or minimal) negative feedback. You'll change your mind. Personally I would never use a solid state preamp.

 

[Jim R]

I agree with Nick. With a budget of $1k or less, in most cases a passive preamp has been much better in my experiences than active tube preamps of similiar price. On the other hand, if you can get up into the $2-3k range then actives often sound better.

By the way Nick, someday you should try some of the higher quality passives (I am assuming you are using the Creek as in your profile). I switched from the Creek to a Placette passive and found it to be in another league. Another great passive is the FT Audio LW-1 and it is cheaper but no remote.

 

[Nick Dangerous]

I did. I compared a tweaked out active preamp (Bottlehead Foreplay w/NOS RCA Cleartop 12AU7's and Auricap output caps) versus no preamp (straight into the poweramp w/volume attenuators). The result?

Skip the preamp!

Bypassing the active preamp resulted in better sound in every imaginable way. Deeper bass, higher extension, more detail, etc, etc, etc. So... out goes the Foreplay!

I'm open to trying another active preamp, but I'm fairly skeptical at this point.

Jim R: The Placette is on my shopping list. I see a lot of people upgrading to it from the OBH-12!

 

[MirandaX]

In all fairness (no insult to the wonderful Doc intended), the Bottlehead Foreplay is a $99 preamp at heart, even with another $150 in upgrades.

It's probably not fair to make global judgments about all active preamps based on just experience with the Foreplay.

The Mapletree Ear probably isn't a fair comparison either, given the crosstalk numbers Lloyd provides. (Does anyone know why they're so high? Is it related to the parallel feed?) The SHA-1 is a decent preamp, if you don't count the low-end performance (this is presumably what they improved for the SHA-Gold).

Compare a modest (say, $500) passive preamp with a similarly priced tube preamp, and I think you might change your mind.

(Also, the output of the ART DI/O you're using is so hot that it's in effect acting as a small active preamp.)

 

[Nick Dangerous]

Have a $500 tube preamp in mind to go against the Creek OBH-12?

BTW, I didn't use the ART's output for the test. It was standard CDP line out.

 

[Dusty Chalk]

Quote:

Originally posted by Nick Dangerous I did. I compared a tweaked out active preamp (Bottlehead Foreplay w/NOS RCA Cleartop 12AU7's and Auricap output caps) versus no preamp (straight into the poweramp w/volume attenuators). The result? Skip the preamp!

Which attenuators did you use?

 

[Nick Dangerous]

The Parasound HCA-1000A has them built in. Very handy.

 

[kelly]

Thanks for all the technical explanation, guys. That sheds a little more light on why I liked the EAR 834L with McCormack amps so much. Active vs Passive preamps have been a big mystery to me and I still don't really have the entire concept down but this thread helped immensely.

Nick,
Here's a project another HeadFi'er built that I thought might be up your alley: http://www.welbornelabs.com/rev2.htm

 

[Nick Dangerous]

I was considering Ron's passive, but it has no remote.

 

[kelly]

I don't think anything has both a remote and a stepped attenuator. I'm not sure how do-able that is--seems like it's one of those trade off kind of things.