Schu Posted February 24, 2017 Share Posted February 24, 2017 I am looking to try a new preamp, and I am really intrigued by the 6sn7 as used by some pre's... since I am unfamiliar with all the circuits that are possible, is it advisable to choose (or help choose) a pre by the tubes it uses? is it merely a gain/output difference? 1 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 24, 2017 Share Posted February 24, 2017 2 hours ago, Schu said: I am looking to try a new preamp Are you into building a kit? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 24, 2017 Share Posted February 24, 2017 2 hours ago, Schu said: I am looking to try a new preamp, and I am really intrigued by the 6sn7 as used by some pre's... since I am unfamiliar with all the circuits that are possible, is it advisable to choose (or help choose) a pre by the tubes it uses? is it merely a gain/output difference? Okay. Are you wanting a tube pre-amplifier, which would have a phono-stage built into the unit, or another line-stage, like the Eastern Electric Minimax you have? Usually they won't call it a pre-amplifier if the unit doesn't have a phono stage. They'll call it a line stage. It's not like some rule or anything, but it just may help you in your search for another unit. 6SN7 is a good linear tube, but in line stage or pre-amplifier applications some can be rather microphonic. They will growl/hum when you get your hand near them, or in a worst case scenario start oscillating (sceaming/howling) in circuit. Don't let that scare you, these are worst case situations. Given the choice between a line stage with a 6SN7 or a 12AU7, I'll go with the 6SN7. But I never listened to 12AU7 in a line stage, just in a 6BQ5 PP amplifier. Usually, 12AX7 is a common pre-amplifier/line stage tube from what I can gather. I would take a big giant guess to say the 6SN7 is a more linear and less noisy tube compared to 12AX7 and 12AU7, once the microphonic issues are resolved. Gain/output differences? You want determine how much gain/output your system needs. I went with a stepped attenuator because I really don't need the extra gain from a line stage in a near-field arrangement. 1 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 24, 2017 Share Posted February 24, 2017 5 minutes ago, mike stehr said: But I never listened to 12AU7 in a line stage That's where I was going. Quote Link to comment Share on other sites More sharing options...
richieb Posted February 24, 2017 Share Posted February 24, 2017 Mike would you agree the 6sn7 might provide a more "tubey" vibe opposed to the nine pins? I've got both but quite honestly can't prove what I just asked! And with this question due you favor tube or SS rectifiers? Once again I am led to believe that an all tube system Must be tube rectified? I've got both as well and as stated can't prove or disprove either design. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 24, 2017 Share Posted February 24, 2017 55 minutes ago, richieb said: I've got both as well and as stated can't prove or disprove either design. I'd probably be the same, couldn't approve or disapprove. As long as it sounds good with nothing objectionable. Regarding a phono stage, I would think noise would be the main factor to be concerned about. A guy should be able to build a tube phono stage with solid state rectification, and possibly have a more quiet power supply with more filtering capacitance. But OTOH, the Scott LK48B integrated amplifier's phono stage I have is all tube. It's quiet...well, not perfectly but lashes rather up well with an old idler drive TT I have. Currently, I am in the process of re-purposing a 1959 Webster Electric (Racine,Wisconsin) ten tube RTR stereo head unit into a phono-stage. The stage used is the RCA 7025/12AX7 RIAA, the circuit is in one of the tube manuals. Then I can listen to the idler drive turntable with other amplifiers than just the Scott LK48B integrated. Eventually, the Webster may/could be built up to a full function pre-amp, with phono and auxiliary inputs. I just scrounged up some nice Grayhill selector switches to use...two position, four, and six position. I'll be using one of those... Quote Link to comment Share on other sites More sharing options...
Coytee Posted February 24, 2017 Share Posted February 24, 2017 4 hours ago, mike stehr said: Usually they won't call it a pre-amplifier if the unit doesn't have a phono stage. They'll call it a line stage. Never knew that, thanks! Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 I like to keep my phono stage/sut separate... I am possibly looking for just a line stage (as you put it). I am intrigued by a passive, because I dont think I need more than 8-12 good watts but I have never owned one and for a few hundred dollars I can get one almost anytime. My current pre is an eastern electric with 6x4 rec, and a 12au7 follower and output. I also need two rca outputs. Tube rolling has been fun, but really once I find that nice combination, I dont change except every now and again to confirm what it is I had been hearing. I really wanted to try that NBS that just passed the garage sale section but the timing wasn't right and the price is really pushing what I would ever spend. I would lovethe cost to be much closer to, or under, a grand Quote Link to comment Share on other sites More sharing options...
seti Posted February 25, 2017 Share Posted February 25, 2017 I'm using a Slagle AVC but I've found sometimes I want just a little boost for some digital sources. I'm going to build a 112A DHT preamp filaments will be dc via rod coleman boards. You can't go wrong with 6sn7 except for price. The 6J5GT is half a 6SN7 and a little cheaper but you need two. Bottlehead.com even has a 300B preamp and if you pay extra they build it for you. If you can find a juicy music merlin grab it. Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 Anyone ever heard of the Aikido Circuit? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 25, 2017 Share Posted February 25, 2017 Yes. I scratch built a pair of mono left and right Aikido linestages with 6SN7, using some old chassis' and parts. http://www.tubecad.com/2004/blog0011.htm Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 25, 2017 Share Posted February 25, 2017 The two best preamps I have ever had were both 6SN7 based. The "Dude" from Paul Weitzel of TRL (wonderful man, may he rest in peace) and a Cary SLP-05. I love the tube and it is a fun one to roll. Some damn fine ones out there. I will regret til the day I die ever letting go of my "Dude". What a friggin' mistake that was. If one has never heard one they would not understand and I cannot even begin to do it justice with an attempt at an explanation. Now Mr. Weitzel is gone and TRL is no more. Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 I read that page before... didnt know it was yours. It seems the Aikido circuit might be problematic if not paired correctly... there is a guy on ebay that builds that circuit. To order for not to much more than I want to spend... uses four 6sn7's. Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 1 minute ago, jorjen said: The two best preamps I have ever had were both 6SN7 based. The "Dude" from Paul Weitzel of TRL (wonderful man, may he rest in peace) and a Cary SLP-05. I will regret til the day I die ever letting go of my "Dude". What a friggin' mistake that was. If one has never heard one they would not understand and I cannot even begin to do it justice with an attempt at an explanation. Now Mr. Weitzel is gone and TRL is no more. Been looking at a cary... there is one available for about a grand, but I like to see the internals and have not on that model. Fwiw,my amp is a cary (sort of) Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 25, 2017 Share Posted February 25, 2017 3 minutes ago, Schu said: Been looking at a cary... there is one available for about a grand, but I like to see the internals and have not on that model. Fwiw,my amp is a cary (sort of) Which Cary Schu? Can't be an SLP-05 for that kind of scratch. Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 Im sorry... there is a constellation for sale on ebay... Quote Link to comment Share on other sites More sharing options...
richieb Posted February 25, 2017 Share Posted February 25, 2017 A small line stage that seems to get great reviews is the Cary subsidary at the time, AES, DJH version, 6sn7 based. Most likely a great match for your Had Inspire. Both the standard or DJH version are reasonably priced on the used market. O even better Shu, have Dennis build what you want around the tube you favor. From speaking with him I know he sometimes uses some rather obscure tube types that he raves about. I also agree with the comment on the JM Merlin. I'd likely buy another if the opportunity presents itself. I've had a Peach and BBerry and found both too noisy for my tastes. Not so the Merlin. Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 25, 2017 Share Posted February 25, 2017 7 hours ago, seti said: If you can find a juicy music merlin grab it. It is really one of the best things I have ever owned. I won't ever sell mine. Probably one of the few things I will take with me to the Philippines when I retire. I like it a lot more than the BBX I had. Bruce Quote Link to comment Share on other sites More sharing options...
Schu Posted February 25, 2017 Author Share Posted February 25, 2017 That 300b bottlehead line stage looks very nice... lots of upgrades going on in the forum, but there seems to be a lot of trouble with noise that is undiagnosed by end users. Quote Link to comment Share on other sites More sharing options...
richieb Posted February 26, 2017 Share Posted February 26, 2017 6 hours ago, Schu said: Been looking at a cary... there is one available for about a grand, but I like to see the internals and have not on that model. Fwiw,my amp is a cary (sort of) 6 hours ago, jorjen said: The two best preamps I have ever had were both 6SN7 based. The "Dude" from Paul Weitzel of TRL (wonderful man, may he rest in peace) and a Cary SLP-05. I love the tube and it is a fun one to roll. Some damn fine ones out there. I will regret til the day I die ever letting go of my "Dude". What a friggin' mistake that was. If one has never heard one they would not understand and I cannot even begin to do it justice with an attempt at an explanation. Now Mr. Weitzel is gone and TRL is no more. There is one of each of these current on US Audio. TRL Dude asking $4250 Dennis Had LP 2 asking $900 Quote Link to comment Share on other sites More sharing options...
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