mopar dave Posted May 15, 2003 Share Posted May 15, 2003 been tube rolling the past two weeks. craig was nice enough to loan me some tubes to try. my amp requires 4 el34's,4 6n1's,2 12ax7's. craig let me try ei el34 big bottle and svetlana's for the el 34's. i tried the ei's first, everything sounded clearer with more detail than the chinese tubes i have been using, but the bass was to boomy and mushy. i think they could sound very good with la scala's, but not on cornwall's with there lower bass notes. next i tried the svetlana's. boy, these tubes are excellent, clean,clear,dynamic and detailed, i like them. next i tried some 12ax7's that i also got from craig. first was a tube labled pro/comp. these were a no go. noisy and no dynamics. next was some tele's. these were much better, but although these had great detail, they were bright or forward sounding and not much for bass extention. so i ordered some svet 34's and some ei 12ax7's as well as some 6n1p's which i received 6h1n's i beleive to be the same tube from triode. first i installed the svet 34's than the 6h1n's. i could'nt tell much difference between the 6h1n and the chinese 6n1's, maybe a little more low end with the 6h1n's so i left them in. next tried the ei 12ax7's. these tubes cover the whole spectrum. great low,mid and high end, to high in my system, but very musical. i like the ei 12ax7's, they sound great at low and mid volume, but on the upper end (95db+) they do get bright or forward may be a better description. so i'm in searce of a better 12ax7. i think i'm going to try a vintage mullard 12ax7 next. can anyone give me suggestions on what to try in this chinese amp? thanks dave Quote Link to comment Share on other sites More sharing options...
AnalOg Posted May 15, 2003 Share Posted May 15, 2003 Mopar dave, If you can, see if Craig has some 12ax7 RCA's you can try, they scored high for me. Tom Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 16, 2003 Author Share Posted May 16, 2003 ok, i'll ask him. he did say he thought he had some mullards that i could try. i'll have to wait a couple weeks, he's very busy rebuilding amps. thanks dave Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 19, 2003 Share Posted May 19, 2003 Is that Audcom ap900 self-biasing, or are you setting bias with each change of tubes? Just wondering because i have the same amp and can't seem to get any info from the guy in LA where i bought it or anywhere else including the chinese home website. thanks, Brett... For all I know it's easily recognizable as to what type bias adjustments are on this amp and i simply don't know enough to see it... Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 20, 2003 Share Posted May 20, 2003 Brett, They give you no particulars on the settings of any of the adjustments under the chassis we tried. Some tech support !! Craig Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 20, 2003 Author Share Posted May 20, 2003 brett, craig's right. we tried getting info on the audcom with no good results. i emailed china and LA, as well as calling LA and florida, were it was purchased. LA told me all they had was a wiring diagram which i did get. other than that i have no other info. the tubes i have been using are matched sets. i have about 300hrs on this amp now and i'm very pleased with it. less than $500 to my door for a nice looking amp with great sonics really suprises me. as for the chinese tubes, i thought they sounded pretty darn good, but improvements can be made with tube changes. with the tubes i'm using now the biggest difference is the clearity. currently using svetlana for the el34's and 6n1's, and ei 12ax7's for pre amp tubes. still looking for a different pre amp tube, something more laid back, but with clearity and detail. what speakers are you using with your audcom? what is your honest opinion of the amp so far? if you find data on it please let me know and i will do the same. also if you do any tube rolling let me know the results. later dave Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 20, 2003 Share Posted May 20, 2003 Hey Dave, I'm currently running Paradigm Reference Studio 100 V2's with my Audcom. I've tried the Svetlana EL34's as well as currently using JJ/Tesla EL 34's. I was pleased with the diff between the stock tubes and the Svets and am just as pleased with the change from the Svets to the JJ/Teslas. I'm currently running Svet 12AX7's and Sovtek 6N1P's. I'm going to be trying various types 12AX7's in the near future as well as swapping around some different 6N1/6922/6DJ8 combos. Sure wish I could get the bias info so I don't damage any tubes if bias adjustment is actually a necessary thing on this amp. Did the bases (root beer colored) of your Svetlana EL34's start to turn a darker color, almost blackish from the heat and is that normal? Mine started to turn darker after only approx. 50 hrs. use. Oh well I just received a new set of Electro-Harmonix EL34's and can't wait to try them on this amp. I'm quite pleased with the sonics so far and as I listen more to the amp and get more accustomed to the overall sound I like what I am hearing. That combined with the fact that you must "burn in" the amp itself as well as the new tubes has been an experience I'm enjoying as the sonics with each seems to change as you put hours on them. I realize my Paradigms are probably not the best speaks (only 91db) for tube amps, but until I make a long term decision as to stay solely with tube equip or to hang on to some of my SS equip I'll hold off on tying up more $$ right now on more efficient speaks.Thanks for responding to my question, let's stay in touch on these Audcoms until we figure out the best respective tube setups etc. Brett Quote Link to comment Share on other sites More sharing options...
Dflip Posted May 20, 2003 Share Posted May 20, 2003 Depending on the power of the amp, you could also look for some triple mica, blackplate 5751's, either RCA Command, Sylvinia or GE. They are about 70% as efficient, so a 30 watt amp is nice. May be okay with a 20 watt, depending on the type of music you listen to and volume. I have a pair of 5751 blackplate GE's and prefer them over the Telefunken 12AX7's. More depth of sound and not as bright. It is a matter of choice. Quote Link to comment Share on other sites More sharing options...
leok Posted May 20, 2003 Share Posted May 20, 2003 E88CCs (6922), ECC88 (can't nemember the US equiv.) are very similar to the 6N1P (check the heater(s)) I know the E88CC has a single 6V heater connection that serves both sections in parallal (thus the 6xxx designation instead of 12xxx). Anyway, there are some very linear NOS E88CCs avail. from Philips, Mullard, and some others I can't remember. Prices vary. I use these in my pp amp, which has no feedback, so linearity is important. I found them to be much better than the 12AU7s that had been in there. leok Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 20, 2003 Author Share Posted May 20, 2003 brett, what are the sonic differences between the svet's and the jj's? yes the basses did turn darn. not for sure, but i think thats normal. stay in touch and let me know how the EH's sound as well as the different 12ax7's. when i get some extra cash i'm planning on trying the rca,mullard and the brimar 12ax7's. dflip, i will give those rca's a try. maybe just what i'm looking for. thanks dave Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 20, 2003 Share Posted May 20, 2003 The jj/teslas seem more open sounding to me than the svets. I've been listening to the EH's for approx 5 hrs. and they too sound more open and a bit brighter than the svets. The jj/teslas seem to control the bass more efficiently than the others as well. I'll have to "burn in" the EH's for a few more hours (overnight or so) to see if they change as much sonically as the jj's and svets did. So far very pleased with this amp, for the money it's surprisingly solid and well built, besides the fact that it sounds damn good, even with my Paradigm Studio 100 V2's rated at only 91db effiiciency. Can't wait until i can pick up a set of appropriately efficient speaks! Considering Klipsch Quartets,do you know anything about them? Beside the fact they're rated at 97 db they will fit nicely between my Paradigms and the balance of my equipment. Stay in touch. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2003 Share Posted May 21, 2003 Ranger, The Paradigm Studio 100 V2's will actually help that amp sound better. Its really on the bright side with Horns ! I got your message just been to busy to give you a jingle I will try today what is the best time to call ?? Craig Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 21, 2003 Share Posted May 21, 2003 Hello Craig, I didn't know the amp was "bright",doesn't appear to be on my setup. I have a good friend who has a mint pair of Cornwalls that I planned to try it on soon. In the meantime what can you tell me about Klipsch Quartets? The jj/teslas sound great on this amp on my speaks. I am trying a variety of things to try and get the best sound from this amp, one thing that troubles me is that no one semms to be able to provide biasing info on this amp. The Svets seemed to run "hot" whereas the JJ's and eh's along with the stock Chinese tubes don't seem to heat up the power tras quite as much? thanks for your help. Brett Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 21, 2003 Author Share Posted May 21, 2003 brett, my amp also runs warmer with the svets. not sure if thats a problem. where do you have the gain switch set at? i keep mine set to high for the best sound, but it makes it bright at high volume. i don't want any more brightness, so i have to be careful with tube selections. i did notice the brightness to subside when i tried the ei el34 fat bottles, but the bass was too boomy. i'd like to try the jj 34's, but not if they add brightness. i'm quite happy with the svet 34's for now. i will searce for a different 12ax7 and make another cable upgrade. later dave Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 21, 2003 Share Posted May 21, 2003 Hi Dave, The jj's don't necessasarily brighten the sound, didn't mean to mislead, simply more detail and openess, due to the fact of the additional clarity on details,(brass,cymbals,etc.) it could seem more bright to some. i believe the additional heat from the Svets could be due to biasing issues. in either case the Svets seem to "shroud" some of the detail in my particular application. I'm currently running Kimber Hero IC's with self-made 12ga. speaker cables. I'm running a Sony SACD player (SCD C222ES) as well as another CD transport with a Margules Audio D/A Enhancer. I may be trying some pure silver IC's as well as silver speaker wire in the future as I heard and read alot of people have good results with silver and tube setups. Stay in touch!, Brett Quote Link to comment Share on other sites More sharing options...
mopar dave Posted May 21, 2003 Author Share Posted May 21, 2003 brett, i'm also using a sony sacd player(scd ce775)and analysis to the cornwall's as well as inside of them. i'm currently thinking about upgrading to a better cable(analysis). i am currently using acoustic researce, a good cable for $12. when i switched over to the AR cable, i noticed quite a difference in the clearity of the music and the brightness was toned down alot. i was using the cable that came with the cd player. so i figure maybe i can improve again with $75 analysis cable over the $12 cable. i will do this before buying anymore tubes. i can't see having tubes laying around that i will never use. you have me thinking about those jj's though. i will search for the correct 12ax7 first. i'll probably try the 5751 rca's first, after the cable upgrade. thanks dave Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 21, 2003 Share Posted May 21, 2003 Hi Dave, Well, tonight I've come to a definitive conclusion about the "brightness" in my setup. After many different variations of music and equipment I'm certain that the Sony SACD player (SCD C222ES) is the source of the brightness. My other cd player (an AMC CD6B) eliminates all signs of brightness/harshness, heard with the Sony,without loss of detail or clarity. I've heard and read other people say the same thing about some of the Sony players,although on SACD format cd's it's not nearly as prominent, and the added bonus of the wonderful fullness of sound with SACDs'makes it worth it. So I guess I'll keep both and enjoy each of their respective good qualities! One of the nice things about the amp is you can listen to either with the mere flip of the source switch. If you haven't already tried I hear the Philips JAN 6922 NOS pre-amp output tubes work well for these bright conditions. BTW the EH EL34's are sounding quite nice too. Difficult choice to establish a clear favorite between the Svets,EH,or JJ/Teslas. I guess at some point I'll probably give the original Chinese EL34's another go as well. Until next time, listen closely,and enjoy that music! Brett Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2003 Share Posted May 21, 2003 Brett, You ready to sell the Sony for a great price ? Craig Quote Link to comment Share on other sites More sharing options...
rangeroo22 Posted May 21, 2003 Share Posted May 21, 2003 Hey Craig, When you say "great price" do you mean for you or me? LOL I tried to call you back today,,phone tag... Brett Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 22, 2003 Share Posted May 22, 2003 For me of coarse Quote Link to comment Share on other sites More sharing options...
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