sunnysal Posted October 31, 2003 Share Posted October 31, 2003 Well the amplifier finally got out of customs today (A little bribery, etc. et voila!) and I came home early from work just to get it back into my system. I decided to give a listen to the outgoing dynaco MkIVs one last time before putting back the JFL amplifier. Just to try once again to see what, and how much difference, there actually was between the amps. I played selected cuts from four or five of my favorite and best known tunes. They sounded very nice...good detail, good dynamics, extension, slam, imaging, whathaveyou. I said to myself, these are great amps I wonder if the JFLs really sound THAT much better? So I then proceeded to install the JFL amp again...Fired it up with my hand hovering over the power switch (just in case), after about five minutes I decided fire was not impending and left the amp running for about fifteen minutues with input but at low volume. I returned after the fifteen minute "break-in" period (LOL!) and sat down to listen to the same cuts... WOW! forget the dynaco, it is going in a closet never to see the light of day again! (anyone want one?) I do not know if Jeff did something to these amps while they were back in Canada or if I had just forgotten how great they sound BUT...in every single measure of what excites me about music the JFLs blew away (I mean it) my dynacos. Depth and width of soundstage, warmth/sweetness of sound, detail retrieval, I mean there was no comparison. I haven´t even begun to tube roll any of my holy grail 6SN7s in yet! The Dynaco MkIVs are arguably the pinnacle of Dynaco´s tube development (at least that is what Dynaco themselves said when they produced it) and I would say many would place it up on a pedestal as one of the best examples of EL34 PP amps. Well FORGETABOUTIT. Dump´em...Sell them...Sell whatever you have to and get yourself a DHT PP amp. Please no flames, I am not suggesting that any of your amps suck or that you are wrong when you say you love the sound of your respective amps. I am just simply relating my experience when switching from one of my past favorite amps to this new amp. I hope my experience might be of some use to those of you looking for amp nirvana. I have found mine. Well gotta go, got a date with Susan Tedeschi, she´s playin´ in my living room now dont´cha´know and she is GLORIOUS. my best regards to all of you, enjoy your weekends, I know I will! Tony Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted October 31, 2003 Share Posted October 31, 2003 Hi Tony, I'm glad you still like the amp! Let say that this beast traveled than 90% of the people on earth. Changes done were few. I did put dual JJ 100 uF caps in replacement of the dual JJ 47 uF. The blown Black Gate cathode bypass cap was replaced. The wrecked copper top plate was replaced by a brass top plate so it shouldn't have change much soundwise. The Hammond 374BX power transformer was replaced by a 300BX so again, nothing much here. If ever you ship it back here, be sure to write in bold letters on the crate "Mr. Canadian custom officer... I swear there is no dope in that wood crate". The idiots at the customs opened everything down to the amp itself, without putting anything back together. Needless to say it sounded loose inside when I recieved the thing. For those interested in jumping in the DIY train, I posted the schematic a while ago here (http://forums.klipsch.com/idealbb/files/2A3PP.jpg). The amp sound pretty good. Sorry guys, it's not an ultralinear but hey!... nothing's perfect... Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted October 31, 2003 Share Posted October 31, 2003 Good to see you back, Jeff. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted October 31, 2003 Share Posted October 31, 2003 Hi Guy, It was just a hit and run... I still have to go through the administrative stuff for my thesis and prepare my PhD defense. At the same time I'm building a PP EL84 as a wedding gift for a friend and I am still working on my own pair of PP2A3 monoblocs (which should be pretty unusual thanks to Mike Lafevre Peerless OPT reissue and Gary Pimm state of the art constant current sources). Oh yeah... I also sold my condo and bought a house... All that in two weeks. Forums are incredible time waster. Quote Link to comment Share on other sites More sharing options...
Deang Posted October 31, 2003 Share Posted October 31, 2003 Tony, are your MKIVs stock or modified? Quote Link to comment Share on other sites More sharing options...
sunnysal Posted November 1, 2003 Author Share Posted November 1, 2003 dean, the dynaco´s are slightly modified, in that old caps were replaced (with sprague orange drops), decent rca input jacks mounted and newer bindging posts (only for 4 and 8 ohms, dumped the 16 ohm) nothing fancy, just decent plastic ones that grip my big cables better than those little screws on the original plate. lastly I wired them for triode strapped operation BUT placed a toggle switch inside (NOT outside since you cannot switch on the fly) to switch between pentode and triode modes. I was semi joking when I asked if anyone wanted them...mostly because I do not think it really is pratical to sell them to anyone since shipping from here would be so damn expensive (it cost me a few hundred dollars to get the up to Jeff in Canada via lowest cost transport) but if you really are interested in them perhaps we could find a way. I have thought of a closet cleaning where somehow I take all my unused electronics to my father´s house in the USA and from there begin the give/trade away. maybe that will happen soon, if so I will let me buds here at the board know about it first. I am currently tube rolling 6SN7s in the JFL amp...after last nights session with the EH6SN7s (amazing sound from a new russian tube!) I started the morning with my 1947 tungsol blackwraps...juicy baby! JUICY! but slightly less extension on top than the EHs, now I am on the Mullard ECC33s, too early to define exactly what I am hearing there, later will come my various sylvanias from the 50´s and 60´s. I am determined today to select a "final" 6SN7, a backup and the rest go into deep storage. I also have settled on the Mullard GZ37 as the rectifier. the U52 and the brimar 5U4G still sound a little better to me BUT after the last meltdown I promised Jeff to use the 5AR4 and variants only from now on. Lastly those sovtek gold grid 2A3s sure do sound good! warm regards from musical el salvador, tony Quote Link to comment Share on other sites More sharing options...
leok Posted November 1, 2003 Share Posted November 1, 2003 Tony, Glad to hear about the amps. I'd love to hear them. I've been very happy with the sound of triode, no feedback, pp. I'd sure like to hear the difference 2A3s would make. Jeff, I just looked at the schematic .. must have missed it the first time around. You made a pp amp that looks simpler than a SET. I gues one thing that is simpler is pp removes all the bias flux from the output xfmr, so no need for fancy parafeed construction. Nice design. leo Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted November 1, 2003 Share Posted November 1, 2003 Tony, congrats on the return of your amp. It sounds like you are really enjoying your music now and probably rediscover some favorite tracks - a bit similar to my situation with the new SVS sub - so enjoy yourself. Wolfram Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 1, 2003 Share Posted November 1, 2003 Hi Leo, Thanks. Yep, it's pretty hard to come up with something simpler than this. Actually I forgot to put on the schematics that I did put some grid stopper resistors. The key of this amp is the IT phase splitter. The Lundahl 1660 does a pretty good job as a phase splitter. Even if it is simple, the number of transformers and choke makes for a crowdy chassis. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 1, 2003 Share Posted November 1, 2003 Jeff, I'm slightly confused by the picture compared to the schematic . The picture shows two transformers for the 2A3 heaters but the schematic only shows one. Why would there be a need for two ? Craig Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 1, 2003 Share Posted November 1, 2003 There is one transformer per pair of 2A3. It's not indicated on the schematic. You could use one transformer provided you have a dual secondary. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted November 1, 2003 Author Share Posted November 1, 2003 I think simplicity results in cleaner, more dynamic sound Anyone in my "neck of the woods" should feel free to drop by for some music and a BBQ feast! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 1, 2003 Share Posted November 1, 2003 Ahh that was the point I was missing the schematic is for one PP channel. But really PS wise the only thing doubled is the 2.5V heater transformers. Craig Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 1, 2003 Share Posted November 1, 2003 ---------------- On 11/1/2003 4:42:47 PM NOSValves wrote: Ahh that was the point I was missing the schematic is for one PP channel. But really PS wise the only thing doubled is the 2.5V heater transformers. ---------------- Yep... If I would to build it now, I would use the Permalloy SA-240-A from Magnequest. They are somewhat costly but these are superb OPTs. Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 1, 2003 Share Posted November 1, 2003 What is with that PP piece of junk! heh... kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 1, 2003 Share Posted November 1, 2003 What's the cost of them from Mike ? I can figure the discount Also could this design be easily adapted to 300B ? Quote Link to comment Share on other sites More sharing options...
sunnysal Posted November 1, 2003 Author Share Posted November 1, 2003 Permalloy SA-240-A from Magnequest? don´t tell me about no darn Permalloy SA-240-A from Magnequest! tony Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 1, 2003 Share Posted November 1, 2003 Jeff, You mentioned the grid stopper resistors -- are they between the Lundahl 1660 and the 2a3 grids? What value are they? Marvel Quote Link to comment Share on other sites More sharing options...
Deang Posted November 1, 2003 Share Posted November 1, 2003 Don't get yourself too worked up Tony. The only people in the neighborhood that would be able tell the difference are the cats and dogs. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 1, 2003 Share Posted November 1, 2003 Marvel: The grid resistors are 1K. Craig: I wouldn't use this configuration for a 300B PP amp. Dean: Meow! Quote Link to comment Share on other sites More sharing options...
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