Best Tube PreAmp under $500???

CH46E wrote: »

With this new Anthem tube pre, it uses 6922 tubes. I have some (6) 6SN7 tubes ( that I use in my Yaqin CD3 buffer) and found that the TubeDepot has some adapters so I can run the 6SN7 in a 6922 socket. Is this a bad idea? I will be buying some 6922s to play with along with the OEM tubes that JayCee is sending.

Just wanted some feedback about adapters.

It's as good idea as, say, popping the GM-supplied engine from your new Corvette & dropping in a Ford GT40 engine.

Why buy a preamp designed to run 6922s if you want to use 6SN7s? The 6SN7's triode sections are not identical to those in a 6922, so the operating points in your new preamp won't be ideal for the 6SN7s. You might like the sound, but wouldn't you be better off going for a 6SN7-based preamp if that's what you want? {This is a rhetorical question }

These are pretty nice and not too expensive. I was fairly impressed with one I had here for a day, courtesy of a local enthusiast.
http://www.tubes4hifi.com/SP14.htm



EDIT: Yeah, the heater current thing (which I wouldn't have even thought to check, which is a severe oversight on my part) is probably a deal breaker. You need to know how much current the filament windings of the power transformer in your Anthem is rated for.
Ask more of it than it is capable of, and the magic smoke will be loosed.

So... the 6922 has a 6.3V 300 mA filament.
The 12AU7/12AT7/12AX7 family all have a center-tapped 12.6V filament. Run the two halves of the filament in series, and the heater current's 150 mA @ 12.6V; run 'em in series, and the current's 300 mA @ 6.3V (Ohm's Law and all that).

The amplification factor of the 6922 is 33 ("medium mu"), which is kinda in between the 12AU7 (mu of 19.5 for triode section 1 and 17 for section 2) and 12AT7 (mu = 60 for each section). The high-mu12AX7 is similar to all of these, but with mu = 100 for each section.

http://www.tubebooks.org/tubedata/HB-3/Receiving-Type_Industrial_Tubes/6922.PDF
http://www.tubebooks.org/tubedata/HB-3/Receiving-Type_Industrial_Tubes/6681_12AX7.PDF
http://www.tubebooks.org/tubedata/HB-3/Receiving_Tubes_Part_2/12AU7-A.PDF
http://www.tubebooks.org/tubedata/HB-3/Receiving_Tubes_Part_2/12AT7.PDF

The 6SN7 is also a twin triode, but of an earlier (and, some hifi buffs would argue, better) kind -- descended from very early indirect heated filament triodes like the 27, 56 and 76 (which are also popular preamp tubes in some circles ).

The 6SN7 has an untapped 6.3 V filament that draws 600 mA (as pointed out by @invalid above) and two triode sections each of mu = 20
http://www.tubebooks.org/tubedata/HB-3/Receiving_Tubes_Part_2/6SN7-GTA.PDF

The 6SL7 is "like" a 6SN7 but with a 300 mA 6.3V filament and a mu of 70 (each triode section).
http://www.tubebooks.org/tubedata/HB-3/Receiving_Tubes_Part_2/6SL7-GT.PDF

The precise operating points of all of these tubes are "similar" but not identical. In many cases they can substitute for each other, but just dropping, say, a 12AT7 into a preamp tube socket designed to use a 12AX7 will not be optimum.

So -- can you do it (swap twin triodes willy-nilly?). In some, even many, cases, yes (and, obviously, depending upon the base configuration of the tubes in question --yeah, you can get "adaptors"). Is it a good idea? Usually, no.

But, of course: all generalizations are false.
Including this one.

Stick with what it was designed around the 6922/6DJ8. They are not too pricey and there are plenty out there in all price ranges. Trust me I understand as I too have a ton of 6sn7 from my buffer. In the last 6mo. I fell off the tube wagon and have had to invest in all different tubes 12at7, 5ar4, 5z4g, 12au7, 12ax7, 6bq5 and many of the equivalents for my last two pre-amps.

stick a fork in me I'm tube done.......famous last words

jdjohn wrote: »

mhardy6647 wrote: »

These are pretty nice and not too expensive. I was fairly impressed with one I had here for a day, courtesy of a local enthusiast.
http://www.tubes4hifi.com/SP14.htm

The Don Sachs line-stage pre-amp is based on the SP14: http://www.dsachsconsulting.com/custom line stage.html In fact, I think there's one for sale in our For Sale section. Yep, found it:
https://forum.polkaudio.com/discussion/192050/don-sachs-model-2-tube-preamp#latest

mhardy6647 wrote: »

Read all about the history of the 6SN7 at
http://vinylsavor.blogspot.com/2014/02/tube-of-month-6sn7.html

I'm surprised the article didn't mention the use of CV181 tubes as replacements for 6SN7. Well...maybe they're not. Here's some skinny on the CV181, or at least one popular version of it: https://www.tnt-audio.com/accessories/shuguang_treasures_cv181_e.html

The article didn't mention the CV181 because thomas knows they are not drop in replacements, but some preamps that use 6sn7 tubes have a transformer that can handle them.

Good info jaycee. I just noticed this preamp has a cathode follower, should be able to even use pretty long cable runs. Lot of preamp for the money.

Joey_V wrote: »

CH46E wrote: »

If money was no object I'd probably have the PS Audio Regenerater. But....$$$$ is an object for now.

You’re not missing much, tried it. Meh.

Respectfully disagree, for my system. Recently purchased the P15 and it's made a significant improvement.

Joey_V wrote: »

I’m sure some of it depends on the power you’re getting in the first place. I compared the ps audio regenerator I had before to something like a torus rm15, the PS product sounded thin and harsh by comparison, likely unable to keep up with instantaneous power delivery. Just my experience. But I’ll never go back to a regenerator.

There’s much more to the sound than just a “cleaner” sound.

Agree, cleaner doesn't always equate to better and the improvement I experience is in depth (front to back), improved bass and clearer/realistic vocals. The depth of soundstage was an eyeopener. Wouldn't call it "clean" or "sterile". Definitely more immersive. From my research, the current generators are a nice improvement over what they replaced.

Just curious. Did you use it with the Boulder or another amp? Which version PSA? I'd assume anything less than the P20 wouldn't do the Boulder justice and probably deserves a dedicated 20 amp line.

I'm not one to part with that much coin without return on investment. Unfortunately, for my wallet, the 30 day round trip didn't happen. Honestly, I'd hoped it wouldn't work out. LOL.

JayCee wrote: »

Joey_V wrote: »

I’m sure some of it depends on the power you’re getting in the first place. I compared the ps audio regenerator I had before to something like a torus rm15, the PS product sounded thin and harsh by comparison, likely unable to keep up with instantaneous power delivery. Just my experience. But I’ll never go back to a regenerator.

There’s much more to the sound than just a “cleaner” sound.

Agree, cleaner doesn't always equate to better and the improvement I experience is in depth (front to back), improved bass and clearer/realistic vocals. The depth of soundstage was an eyeopener. Wouldn't call it "clean" or "sterile". Definitely more immersive. From my research, the current generators are a nice improvement over what they replaced.

Just curious. Did you use it with the Boulder or another amp? Which version PSA? I'd assume anything less than the P20 wouldn't do the Boulder justice and probably deserves a dedicated 20 amp line.

I'm not one to part with that much coin without return on investment. Unfortunately, for my wallet, the 30 day round trip didn't happen. Honestly, I'd hoped it wouldn't work out. LOL.

I never run the amps through the conditioners or regenerators. Just an easy load aka source components. Preamp I don’t either.

I tried just last night, the boulder into the Torus. With the Boulder on, the Torus makes a hum. With it off, there is no hum within the unit of the Torus.

Listened. Cleaner but also I lost sense of forward soundstage.

Sad. Even the torus can’t handle the boulder.

I don't think the p20, ps audio's biggest regenerator doesn't have a transformer as big as the boulder 2060. I would want the transformer to be way bigger in the regenerator than the one in the amp.

invalid wrote: »

The p20 has a 2000 va transformer, my amp has a 5000 va transformer.

Krell ?

JayCee wrote: »

invalid wrote: »

I wouldn't run an amp off a regenerator, especially one that has a bigger power supply than even a p20.

My bottom line is, especially w/return policies that allow a trial period, I may only be out a shipping cost. Wife and I ordered Thai takeout last night. Sixty-five dollars later and I have nothing to show except a reason to workout. Skip takeout and try stereo equipment. LOL. I totally trust your and Joey's experience with your own gear but would caution other folks looking....to not take our collective experiences as gospel.

P.S. @CH46E, sorry for derailing your thread. We actually have a few good threads this would be more appropriate.

Skip take out
Try audio equipment

Yes sir. I agree!

I can relate to that.

I could never afford some of my gear new, but it becomes more affordable used.