Sonic Frontiers SFL-2 Preamp

Northwinds

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#21
Dynamics require a high slew rate which tube stuff does not offer. You could try adding something like a Pioneer RG-9 which will give you more
 

braxus

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#22
I don't really want to muck up the sound quality by adding yet another piece in between the pre and amp. I talked to the stereo shop here and they suggested rolling tubes may help this situation. Plus possibly changing some internal capacitors and resistors to help out. I'm going to put the stereo on for a bit more after this to see if anything changes my opinion. I knew tube amps were slow, but I didn't think it would effect preamps as well.
 

braxus

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#23
Well I think I may have goofed with this purchase. It still squashing dynamics to some degree and I noticed its even rolling off the high end a little bit. And though there is a sense of air in the music, I'm not getting space around instruments like I was with the Rotel. Its like its making false space in the music by synthesizing air, yet I can't tell one sound from the next in terms of where it is placed. It still a nice sounding preamp, but I think I might relegate it to a secondary system instead and look for a YBA preamp. I know solid state is probably the sound I'm after, and I already have a YBA amp. So I should be happy with a YBA preamp. Now to figure out what they offered in preamps that isn't going to kill me on budget. I see the Passion as an example, but its way up there in price. I don't remember what preamp I was listening to in the 90s when I first heard YBA. I don't think tube rolling is going to fix my complaints with the pre, as others have pointed out- its the tube sound I don't like. Meaning slow, not dynamic, etc.
 

braxus

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#25
I'm just learning I don't like what tubes do to music. I liked the smoothness of tubes and the air they produce, but it also rolls off the extremes and squashes dynamics. Its too late to return the piece since it was a private sale, so I'll probably hold on to it anyway. Unless someone offers me 100% of my money back. I do have the boxes they were in. I don't know if modding this pre will help my concerns.

I'm finding out I'm very fussy when it comes to sound quality. I've gone through numerous pieces of gear over the years and rejected many of them. I'm finding I'm leaning back on to the sound I heard in my 20s in the 1990s.

I've placed a wanted ad for a YBA 2 preamp.
 
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Northwinds

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#27
RG-9 will not add anything unfavorable to your system, just variable dynamics. It has a very low s/n ratio also. You could also snag a ADC DSS-100 or dbx expander
 

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#29
Too bad, Scott. Hopefully, you"ll find the right combination.

Nando.
 

braxus

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#31
Checking into my options at the moment. Some people suggest my tubes may be worn out or too cheap. They are the $12 JJ tubes in this thing, so that could be part of the problem. I have a buyer coming over on Monday to check out the pre. If he takes it, I have options to see what pre I'll get next. There is another SFL-2 for sale, but that one has the upgrades and also newer tubes in it. I've asked that seller to answer my questions on dynamics with his pre. If it turns out that its only because the one I currently have it worn out, then maybe I'll get that other pre and try again. Unless I get the one seller to sell me his YBA 2 pre that he has currently in a package deal. So hopefully I'll make some decisions in the next few days. All depends on the answers I get.
 

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#32
Scott, I came up from an old Usenet newsgroup about antique radios and phonographs in the late 90s and like they taught me to be highly doubtful about 'reforming' capacitors, so too did they instill in me that tubes are tubes, they can last 60-80 years or die in a short time. The only way to know for sure is to TEST THEM.
 

braxus

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#33
Well if these tubes were in the pre for most of its life, or maybe the seller did a dirty and swapped in old tubes, taking out the good ones. Maybe then I have reason to doubt. These are cheap $12 JJ tubes, so they can't be very good in performance, or they wouldn't be so cheap. That said how much a difference the tubes I'm using would be compared to better newer tubes I don't know. These are the answers I'm currently doing research on. Hopefully that seller of the upgraded SFL-2 will chime in for me.
 

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#34
Are you going to keep the amp or sell it as is to someone who will fully understand what the situation is and will rectify it themselves?

The chances are good that somebody who answers your FS posting already knows what it's about and may be willing to tackle that themselves.

It's not a used car type situation in this case. You might even take a small hit but I'm sure you can even find a trade if you look hard enough. Give Canuck Audio Mart and USA Audio Mart a good browsing and it shouldn't be hard.
 

braxus

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#35
Are you going to keep the amp or sell it as is to someone who will fully understand what the situation is and will rectify it themselves?

The chances are good that somebody who answers your FS posting already knows what it's about and may be willing to tackle that themselves.

It's not a used car type situation in this case. You might even take a small hit but I'm sure you can even find a trade if you look hard enough. Give Canuck Audio Mart and USA Audio Mart a good browsing and it shouldn't be hard.
My thoughts are this. For $400 more I can get an upgraded SFL-2 with newer better tubes. I can't do that price on the same mods for my current pre. If the SFL-2 pre, even upgraded, doesn't sound the way I like, then I still have the money from the sale to get a different pre. Assuming this pre does sell next week. I don't fully know these pres to know how they are supposed to sound, so whether the one I have at the moment is truly faulty or just operating as it was supposed to stock, I'm not sure.
 

orange

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#36
It's not worth it, Scott. Put the money into improving your car situation and let us help you out with the pre.
 

braxus

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#38
Here is the response by the seller with the upgraded SFL-2 pre:

"When I received the SFL-2, the tubes were JJ 6922 tubes which the previous owner already put a lot of mileage on it. My initial experience - the SFL-2 is very quiet; does not sound like any tube preamp I had before...very neutral and very dynamic. When compared to my passive preamp (I have quite a few on hand), the neutrality of sound is actual on par when compared to my Luminous Audio's Axiom Signature passive preamp (with Walker's Mod). That says a lot about the neutral sound of the SFL-2. But it beats my Axiom passive preamp with loads of dynamic and the mid bass is a lot more realistic than all the passive preamps I have on hand.

About a year ago, I came across another gentlemen in the States who was selling his eight NIB Amperex Bugle 6DJ8s and I got them all. I then phoned Chris Johnson and asked for his advice on where (and how many) should I put the 6DJ8 with the best results. Chris mentioned that, to be most cost effective, only 2 tubes will make the most difference (I believe he mentioned LV1 and V1). But he also mentioned that all tubes are interrelated in the circuitry and and the other tubes put into the SFL-2 will also affect the overall sound of it. As such, I replaced the eight JJ 6922 tubes with my Bugle Boy 6DJ8 tubes. Since I am not an expert in fine tuning the SFL-2, I brought the preamp to Partsconnexion in Oakville and the technician over there adjust the preamp to the manufacture's specs. I also have them installed eight brand new Pearl Tube Coolers before I picked them up.

The sound after retubed with eight 6DJ8s.....I would say the dynamic is a bit more enhanced and more quiet. The biggest improvement is in the soundstage arena. I cannot say the soundstage is wider but definitely the sound stage is much deeper (the sound stage is not wider probably due to my Sanders 10C electrostatic loudspeakers).

So you mentioned that your experience with the SFL-2 was not that favourable, sort of mellow.....that is not my experience at all, could that be your friend's setup at that time? As I mentioned, the dynamic (to me) is one of SFL-2 strength and the sound is very neutral...not the classic tube sound at all."
 

Northwinds

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#39
The 2 is a totally different animal, you might like it but remember the hassle of biasing all 8 tubes when you replace them. This is why I personally like a no hassle higher quality SS preamp. You just turn it on and it does the job. I like tubes for guitar amps, not so much for home audio. Some people say a tube preamp sounds great w/ a SS amp but my Perreaux slaps the shit out of any tube preamp (I have only had a Fisher and a McIntosh tube preamp so I have no experience with the boutique stuff. The Acurus SS is the other one popular here. I keep an eye out for one w/ the phono mod, maybe someday
 
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braxus

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#40
I've read in more then a few comments this pre is supposed to be very dynamic. So it seems to me like I got crappy tubes in this thing causing my sound quality issues. Getting good 6922 tubes would be a problem, as they are becoming harder to find. This pre needs hearty tubes to last. And usually when installing new tubes, this pre needs to be rebiased. So now I have some thinking to do. If my pre sells on Monday, I think I'll get the modded one for sale. If it doesn't sell, I'll just get mine fixed with new tubes and possibly a few mods.
 
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