rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jun 22, 2006 21:31:49 GMT
I have a pair of vintage "rebranded" Stax cans that for what they do well they do very well (acoustic music) and am fishing for suggestions on an amp to drive them. Anyone here build this amp ? www.dddac.de/tp08.htmPresently I use the Gilmore "All Triode" amp in the cap coupled version ( with a totally different front end and driver ) and am mostly happy with it headwize.com/projects/showfile.php?file=gilmore_prj.htmHappy but a bit restless......... ;D other candidates : Gilmore blue Hawaii,can get a bit pricey but pretty close to the STAX reference amps which tend to be even more pricey not to mention all that real estate it takes up headwize.com/projects/showfile.php?file=gilmore4_prj.htmTube CAD article-potentially a starting point for a scratch build all original design www.tubecad.com/november99/page6.htmlwww.tubecad.com/december99/page2.htmlthere is this,something I have a real urge to make for a while but never have (yet ),mostly because there is no pressing need saince I have a fully operational amp already www.bonavolta.ch/hobby/en/audio/hdgsta.htmCouple of others floating around but truth is I am hard pressed to beat the original trafos interface coupled to a good 20WPC Class-A amp and the cost of building an ES specific headphone amp making little sense if what I have is not only better but less costly than the alternatives. Open to comments
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Sept 15, 2006 19:20:14 GMT
Well I am now "ampless" due to my canibalising the Gilmore ES amp for another project I did this mainly to force myself into whipping up something new and have norrowed down my choices to two : 1-Single Ended 6BX7 Output- www.audiodesignguide.com/my/stax_amp2.html2-Push-pull EL34 Output- www.bonavolta.ch/hobby/en/audio/hdgsta.htmI am a big fan of single ended sound but one thing I know about Stax Headphones is they do like the juice ! Hit them with under powered amps and the sonics suffer so while the single ended amp apeals to my senses on one level my "head" tells me the PP EL34 amp would likely be a better match. Changes to the schema shown ? 1-Maybe realise the entire front end with Octals,maybe even solid state (Class-A mosfet ?) or maybe not.Likely do a modular breadboard build and plug in the various front ends then evaluate for best personal satisfaction level 2-modify the bias to "low bias" instead of "pro bias" due to my cans being an older/re-branded Stax model 3-"Mogo Power" section.Hybrid rectifier (big fan of the hyrid rectifier lately ),choke input filter section,possibly regulated (tube reg).This is where the cost will rise in a dramatic curve compared to the actual audio circuit and will bring it close to the Ciuffoli 6BX7 in cost (all that Lundahl iron is not cheap !) So in the "pencil to paper" stage of re-working my electrostatic headphone system.For now it is back to the Nelson Pass 20W Class-A Amp and the transformer energizer since all my other amps are way underpowered for driving the Stax combo properly.This combo is pretty good and the one I use for evaluating other electronics because it I so damn accurate I can pick out minute details and identify problems/areas of concern that would be glossed over if using loudspeakers in an open area where room colorations add to the overall sonic profile.....and that is the problem with the combo ! It is so literal as to be close to bland so needs a front end preamp that tends to the lush/romantic rather than dead accurate for any shot at enjoying music.This is cool on "system -2" only if used totally with the Pass/Stax combo but since it is not and the "intentional coloring" is not only not needed but is a detriment when listening to other transducers (dynamic headphones,speakers) and no way i justify running two preamps so something gotta give here and it is not me ! Oh yeah,there IS an option #3 : build a straight power amp using EL34 or 6L6GT in "PP" with a Triode/Pentode switch,update the ancient Stax transformer interface box with better/modern transformers and an improve HVPS (Hexfreds) and just hang it on the output and call it a day ;D I HATE decisions like this when the final project cost will be so high making the initial decisions more important.Whipping out a simple little opamp/buffer headphone amp or even a discrete transistor headphone amp then deciding it sucks means I am only out $20 or so but making a wrong choice here means eating $200-$300 just in hardware if the decision a bad one.There is nothing cheap about high voltage audio work and worse when it is for headphones where everything is magnified by the close ear/transducer couple.
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xerxes
Been here a while!
Posts: 1,115
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Post by xerxes on Sept 15, 2006 21:40:26 GMT
Whichever one you build, be sure and get a box big enough to fit all the insides INSIDE.
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Sept 15, 2006 21:53:27 GMT
"ooooh,a wise guy"Woob...woob.....woob woob woob woob woobNyuck
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Post by southpaw on Sept 15, 2006 22:32:56 GMT
I'd love to be able to add something useful Rick. I ve only had one valve amp (El34's) so I couldn't comment on the difference. But from reading the macho post the 6bx7 one dosen't quite look macho enough. Question is could you beef it up?
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Sept 15, 2006 23:38:22 GMT
PSE connected output device (Parallel Single Ended) but likely not optimal. Wanting to go single ended somtimes needs to take a back seat to reality and in this case about the best that can be expected is 1 Watt or so for a single 6BX7 which you can effectively double for PSE operation though the transformer would need to be changed to reflect the lower impedance on the output so would be a new animal. This is not strictly about sheer power like when electrostats are used with a transformer interface and power amp (like my Pass/stax setup) or my Gilmore would have sucked and it did not www.headwize.com/projects/gilmore_prj.htmbut I always felt I was missing something in the dynamics department while having a suspician it was not headphones being the limiting factor even though they are a bit dated and are low bias unlike the modern Stax cans. Also there is the Stax Corporation itself.every single stat amp I know of named "Stax" is a push-pull class-A design and that no matter if the ss or tube designs.If anyone knows what drives the cans best it would be the manufacturer of those cans right ? So along those lines the simplistic purity of SE likely should give way to the the reality of the symmetrical drive and a serious output stage.Likely it is all about dynamic headroom in the top of the line stax amps and not just playability though just a guess on my part until the actual "bloodshed" of a Rickmeister "rip-off"...um...I mean "clone" amp time to start gethering more parts I guess ;D
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