Which Preamp Audio Research LS3B or Sonic Frontiers SFL-1

Right you are adg101. 

Kitch29 I think is referring to the LS2 rather than the LS3. The LS3 was a solid state unit as the LS2 was a hybrid design. I'd for sure pick a LS2 over the LS3 but expect to spend a bit more?  Both the standard LS2 and LS3 where singled ended; the B designation behind the model number was the balance version. I believe the balance versions were a $500 option and not sure they were a true balance design but just added XLR connections.

A tube preamp, even a hybrid is going to give you the option to roll tubes in and out to flavor the sound to your liking; whereas the LS3 it is what it is unless you do some cap modding which could be hit and miss and you better know what you're doing... plus it likely will devalue it some. You'd spend more on great caps than it's likely worth. Better just to move up to a better preamp than spend money on a LS3 if you're thinking of modding it.

Again the LS3 is a nice preamp for the money. Sure you could go out and spend a little more for something like a Parasound P5 with a lot more options and full remote control, but I bet the old ARC LS3 is more neutral. I've not compared the two side by side but I've heard the P5 plenty and for the money with all its options it's a very nice unit, but I'd take the old Sonic Frontiers or ARC over the P5 if I only needed a line stage. Only negative with the older units is no remote.

Also remember with a hybrid preamp you'll have the tube maintenance cost which is not bad; nothing like power amps. Some rare NOS tubes can get spendy. Tubes will last a long time with normal use. Just don't leave the unit on and forget about it. The SF SFL-1 only has a single tube so it's affordable to run.

My SFL-1 with a Telefunken 12AT7 was a very neutral, good sounding unit. That's a years ago memory, though. 

The ARC LS-3 I recall, also years ago, was a balanced version of the LS-1 which was the Line Stage of the SP-9. I performed the "accepted" mods to m y LS-1 removing all the white by-pass film caps, replacing the 100uF electrolytic in the power supply, upgrading the output caps to Obbligato oils, and using an Amperex 7308. 
Those mods improved the soundstage, tone and texture but it really came alive when I shoe-horned a TKD volume pot in place of the Alps.
I miss that unit... Damn this hobby!

I auditioned the LS3 against an Audible Illusion 3a, Conrad Johnson Pv2, and a First Sound Passive.  It's all subjective and depends on the system, but I thought the Audible Illusion pumped up the sound too much, the Conrad Johnson was too soft, the First Sound was kinda lifeless, and the LS3 seemed to get things right, delivered clarity, kept the meat on the bones, and got out of the way.  I eventually kept a Pass AlephP, but didn't think it blew away the LS3.

SF SFL-1 $500 +/- 
SF SFL-1 Signature $700
ARC LS3 $700 +/-
Herron VTSP-1 $1400 +/-

Never listened to the Herron pieces but have read many great things about them. Won't argue its likely the better prramp but it's going to be maybe twice the money I think.

Any of these preamps are going to be a nice step up from the Nak. I think you started with you can get a great deal trading your Nak towards a SF or ARC. If your friend with the ARC is local try it first. I still would take the SF over the ARC but you can't demo it unless the other person is local too. 

Forgot to to mention prior to my SFL-1 I had a ARC LS7. The LS7 never did it for me. The SFL-1 was musical and I enjoyed it. For what I sold it for I should have just kept it.

Is that "minimal sum" more than a better performing used Herron VTSP-1 cost? 

@edenton925 ... just FYI, the original Sunfire 300 is not a fully balanced amplifier. (Years 1996-2000)

If your amp has "300 - two" printed on the lower left faceplate, then it has a balanced design. (Year 2004, aka the Sunfire 300 x 2)
Input sensitivity for rated output
Unbalanced: 1.64 Vrms
Balanced: 0.82 Vrms

http://www.thecarversite.com/manuals/mandir/Sunfire%20300X2%20600X2%20owner%20manual.pdf

If you can trade you Nak CA5 for a ARC LS3B straight across I'd do it. If he'll let you take it home to see how it sounds on your system do that first. I had a friend who had a CA5 and I'm pretty sure the LS3 will outperform the CA5. The LS3 was a nice preamp but very revealing so if your system is a little bright or thin the LS3 might not be the right choice. The Naks going to be less extended on top which will appear to be warming sounding. 

Be be curious to hear your opinion if you can compare the two in your system.

i wouldn't discount the SFL-1. With the right NOS Mullard in it will compete with anything in its price range if you buy it right. I owned one so if anyone thinks you can do better I'm curious what it is. Yes... if you can spend $400 or more I'd go back to the ModWright SWL 9.0 SE. Your first two choices are nice preamps if you buy them right. Trading straight across for the ARC is a no brainier in my opinion; at least drag it home to compare.

Cheers

atmasphere- Yeah probably--but one guy now (with the SF-SFL1) just wants to trade for the Nakamichi as it has phono inputs--and I have a friend who is willing to sell his ARC LS3B for a minimal sum. Why-- what do you suggest?

japhant-- My serial/production number starts with 97--why?

Edward-
is your Sunfire amp the 1st gen from the mid-90's ?

Is there any particular reason you are looking at these two preamps? IMO there are a lot of preamps out there that might do you better for the same money.

adg101--

Thanks for giving such detailed  and sound advice. I really appreciate it. 

All the best,

Edward

I once owned the SF SFL-1 and it was a nice piece for the money. Funny you post this because when I had the SFL-1 I dragged it over to my dads system to compare it to his ARC LS3. Guess what? He ended up selling the LS3 and bought a SF Line 1. Now the Line 1 is a better pre of the three and has remote, and six tubes in all. 

The LS3 was a great SS preamp in its day -Stereophile A rated I recall. The issue was it was very neutral and on SS amps it could sound a little lean and bright. SS amps at the time weren't anywhere where they are today. On a tube amp is where this pre belongs and I bet it would be nice.

The hybrid SFL-1 was a really nice pre but the single tube does make a difference and with a modern tube it was ok but throw in a NOS tube and it was another story. I really enjoyed mine.
If you're looking for a fat tube sounds it's not that. I bet with your Sunfire amp the SFL-1 will be a more pleasing sound.

A ModWright SWL 9.0 SE will hands down smoke the LS3 and SFL-1 and it has remote. SF Line 1 is another great preamp and it say is more in the league of the SWL 9.0. 

Back on topic; if you want to listen for hours buy the SFL-1 and enjoy the music. If you want to analyze the best 20 seconds of a song to compare the difference between this interconnect and that and not enjoy the full song, buy the LS3. The LS3 is a nice pre but I'm not sure I'd throw it on a big SS amp.

Good luck