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Or is it just my imagination. I recently replaced my previous preamp that I used mostly in passive mode with another that is active. I can't compare them directly because I sold the old one before I got the new, however I have the distinct impression that I'm liking the new, active preamp better. The improvements I think I hear are (i) stronger dynamics, (ii) more musical highs, (iii) a more natural, perhaps deeper, soundstage.The factors I can think of are the following:
First, passive impedance matching issues: I'm thinking this is NOT factor. My pass pre had output impedance of 1200 ohms and my power amps have input impedance of 100,000 ohms, viz. 1/83.
Second, my new preamp has fully balanced outputs; this is what my power amps prefer according to the manufacturer. Perhaps this accounts for the better dynamics. (My passive preamp did not provide fully balanced outputs when used driven by single-ended inputs.)
Third, my new preamp is tube. Can passing the signal through tubes actually improve the sound? How could that be?
My equipment:
- Old, passive preamp: Adcom GFP-750, used in passive mode.
- New, active preamp: Sonic Frontiers LINE 1, tube.
- Power amps: Monarchy SM-70 Pro's, solid state, used as monoblocks and connect to both preamps via 6 foot XLR cable.Bill Bailey
___________________________________________
See my stereo config
Follow Ups:
I have heard only one passive that lived up to the billing of "passive" and could go toe to toe with the best active pres I have heard. It is made by a German company called Purist and surprisingly it is a resistor based control not TVC. I was skeptical, having tried several passives that didn't live up to claims but this was really invisible and had no apparent loss of dynamics.That being said there are many preamps that can be had which are significantly better sounding than the SF line 1.
... to have such a conclusion, what system you used, what source etc.properly set TVCs are sonically superior products to any active preamp within a similar price range.
"properly set TVCs are sonically superior products to any active preamp within a similar price range"What tests have you conducted to conclude this? Which actives did you compare them to?
I have used the Sonic Euphoria TVC and numerous resistor based ones. I have some colleagues that have experience with the S&B based TVCs and they reach the same conclusions with similar active devices. Only the Purist resistor based one I have tried so far gives satisfactory results but it is also not cheap.
I'm a fan of yours and your opinions are always well appreciated by me.My choice of the SF Line 1 was very much influenced by a low budget and the desire for balanced outputs in a tube preamp. If you have suggestions that that meet those criteria, I'd love to hear them.
Bill Bailey
___________________________________________
See my stereo config
What is your budget?
Alas, I won't have a lot to spend any time soon. Assuming I could sell the SF for what I paid exclusive of shipping, (US$900), I can't manage more the $1000 plus shpping, etc., (or a little more from a Canadian seller if I can find one).
Bill Bailey
___________________________________________
See my stereo config
For around $600 (for the kit) the Transcendent sound Grounded Grid preamp is very good (even better with a couple of simple mods). This includes the very nice 24 position stepped attenuator (pain to solder all those resistors but worth it). It creamed my Audible Illusions M3A for example.
As I posted a few days ago, I recently purchased the Conrad Johnson CA200 control amp, which is a 185 wpc ss integrated based on the Premier 350 power amp with a passive linestage.I extensively home auditioned it against my MF2250 power amp with a Premier 18LS ss preamp and the new CT6 tube preamp (essentially the 17LS's replacement).
No question the 18LS / MF2250 had a much more forward presentation and the CT6 / MF2250 had a rounder, fatter presentation. In comparison, the CA200 is leaner. A bit less lively than the 18LS and less warm than the CT6. But the CA200 is much more transparent and neutral and detailed, while still maintaining a sweetness. I had no idea how much noise the other two preamps were adding until I compared them to the CA200. The 18LS and CT6 seemed to color the sound, although not unpleasantly. The CA200 really cleared things up though, and not in an unpleasant or analytical way.
Of course this is all CJ stuff, and a small universe of it at that, but I think I now understand a bit what is good about passive and what is good about active.
Hi Bill,It is very interesting. When I loaned you the SM70-Pro and the LW-1 for home trial, you did not even bother to connect the LW-1 and thought your Hoffmann was pretty good preamp. And now fast forward you tried the Adcom and back to an active, sounds like a merry-go-round to me. Since you are using a SF line stage now, you may be interested in the review of our LW-1 by Soundstage because the reviewer compared it with his heavily upgraded SFL-2. It would give you an idea what a properly designed passive sounds like.
I don't think I can post link here but it is not difficult to find from the site.
Hope all is well with you back on the prairies!You're right: it's been a long, tortuous route. I do consider the Apt Holman a great preamp, (they are a real steal on the used market). I traded to the Adcom a much for the remote control as thing else, although it is at least the equal of the Apt in passive mode, although it is too bright in active mode.
I traded to the SF Line 1 because (1) I wanted balanced outputs -- the Adcom provided balanced outputs but only in active mode, and (2) because I wanted to try tubes.
Whereas the LW-1 might sound great, it wasn't and isn't what I was looking for. As you know, the SM-70 Pro's prefer balanced inputs. BTW, I am kind of sorry I didn't get them from you back then since they are a great amp. On the other hand, I eventually got they directly from Monarchy as factory seconds for less than you were able to sell them for. I know: the market sucks :-(
Bill Bailey
___________________________________________
See my stereo config
Its really too bad that the Monarchy M24 DAC/pre doesn't have balanced outputs because it is one smokin hot DAC/pre. I use it now and love it.
As part of my wonderlust quest to figure out how an active could better a passive, discovered active tubestages can do things passives can’t. Depending upon your definition of better, the “improvements” maybe the results of active circuits correcting something (like somesort of impedance issue, etc.) or simply the addition of valves offering some sort of coloration that seems to be more "musical".Passives do degrade slightly on the subtractive side and can’t help or add anything. Unfortunately, most actives just get in the way (adding a layer haze or veiling) and / or mucking with the signal (trading something like warmth for articulation, liquidity for pace, etc). The only actives that could provide a strong enough argument in its own favor by creating the body, life and realism that only tubes seem to be able to provide with the least amount of loss in transparency over my passive are pretty far up the food chain.
If you found some that works better leave it alone, but the only way I know for sure to tell exactly what a preamp is doing is to compare it to a direct connection. DON’T TRY THIS IF YOU ARE UNSURE OF WHAT YOU ARE DOING….BAD THINGS LIKE YOUR SPEAKERS OR AMP COULD BLOW UP. Having no volume control is not practical and DANGEROUS, but connecting a cd player directly to an amp “commando style” with no volume control device in the loop yields the truest signal.
This is over my head, but active advocates feel…The input/output buffering circuits found in most active and buffered-passive preamps offer an advantage in is it’s ability to lower the output impedance to just a few ohms and provide a constant output impedance for the power amp to work against. Without a buffer stage, passive device may sound its best in a very small portion of the passive unit's control range where voltage and current requirements are met. Secondly, the filtering act like ac conditioners that may condition the low-level source signal from digital sources resulting in more - more drive, more heft, more body, greater dynamic peaks.
Firstly, the Adcom GFP-750 is good but not great in passive mode, in my opinion. I owned one.So, there are many preamps both passive and active that can sound better than your present passive setup. When I ran the Adcom GFP-750 in passive mode it softened the dynamics making the overall presentation a bit dull compared to active. This did not happen with the Placette passive unit. In other words, the Placette didn't kill the dynamics like the Adcom. And the Placette was significantly more transparent too. I would take the Placette passive any day over the Adcom GFP-750 in passive mode.
Many active preamps will veil the sound slightly compared to an excellent passive. On the other hand a good active can sound more robust and "alive". I especially liked the Cary SLP-05 vacuum tube preamp.
Just my 2-cents worth.
I'm always glad to hear your suggestions.The Adcom is gone now and I'm using the Sonic Frontiers. Overall I prefer the SF. Given I was looking for tubes and fully balanced output on a very constrained budget, I had relatively few options. The SF fit the bill: I'm not disappointed.
Bill Bailey
___________________________________________
See my stereo config
I agree Abe. This is the guy who bought your SLP-05. If you liked the Cary, you should hear a Audio Research LS 26! The Cary has long been sold.
Start another thread and give us a review of the LS26! I thought the SLP-05 was wonderful. How does the LS26 differ? We want more. ;-)
nt
> > passing the signal through tubes actually improve the sound < <Tubes may improve the beauty of presentaion but not necessarily the accuracy.
Agreed, but it sure sounds nice!!!
"David! You can KILL a man with a chopstick!" -Keith Charles, Six Feet Under
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