Bias issue for the 6L6 (GC) is resolved.. !
According to the techs at AV123 (in their reply to my Email) they have suggested that the Bias voltage remain the same as for the 5881 power output tubes. That Voltage is: 1.15VDC. Since the makeup of the 6L6 is basicly the same, and the output is at the same level, an increase in voltage would not be justified. Soooooooo... There we have it 1.15 Volts.
As a side note, I rec'd my JJ Electronics 6L6GC's and I immediatly stuffed them in the SP-3. I set the Bias Voltage for a Buck-Fifteen. I then waited for the explosion, molten glass slivers in my eyes and nasty noises from my schredded speakers. None of all that, BUT there was plenty of the "needle wabble" and "the Numbers Dance" that indicates a journey ito "Tube Ocillation". I just cant spell at all today... any day actually, but I am really having tough time with it today.
Hey Modereator...... SPELLCHECK (please).
Anyway, Out go the JJ's. I still have a Quad of China Electron 6L6's that came with the deal, so when I get my nad's back I'll give them a try.
All for now...
Tubby |
we will hope for the best Tubby but for some reason ...they are silent on this issue ????
let us know ... |
Bernard991,
I put the Bias question directly to AV123 this morning (by Email). I will relay their response. I also suggested that they take some time to follow our threads (here on Audiogon).
Tubby |
well no luck getting a response from Melody ....not sure what to make of it ? I was told that if a bias circuit was a 'good' design then it would not allow you to go past the point that it could not safely sustain ....but who knows what kind of a circuit we have ...?? |
I would like to think that there is a "magic" bowl that is always filled with new (and replacement) amps at AV123. As reality may have it, however, we are perhaps Guinney Pigs stuck in a tub of volts.
Being the dumb A that I am, I have the honor of using the "new and improved" version of "WebTV". It will not allow me to access the "Melody" website. ... Just about, but not quite. I "can" get on the "Euro." version, but it is in French (or something like it).
Melody (in it's own right) is big Doo-Da in Europe. Melody makes (or engineers) a gaggle of amps (plus some other candy). They must make amps over in Australia to keep their minds off the sharks. Although I have know some sharks that were Audiophiles (check under "Feedback").
I now have 2 quads of 6L6's coming in. One quad is from JJ and another a China Electron. I'll start at 1.15 Volts to 1.4/5 Volts. I will understand that the lower D Volt D higher D Ampre (say Ohm-me). I just don't want to take out the resister that is there (just waiting) for me to do that. |
totally agree Tubby !
maybe this might bring some much needed information to us re the BIASing issue .....
its hard to imagine how there are no schematics out there ...what happens if one actually breaks ? |
Can anyone find an "open door" (so to speak) to the techs or service at Melody Audio in Australia ? I believe that they would be the ones to have the most expertiese in the Bia's and limitations of the SP-3. My only hesitation would be a gentle "toe stepping" on AV123 or perhaps causing a potiential problem between Melody and them.
However:
It is important for us (the owners and potential owners) to know the operational parameters of this fine amp. The "known" is:
5881's, 6l6's and KT66' all have different bias voltages (as: 6550 vs KT88/KT90).
(just cant seem to spell today). Any-who, It is the fine folk's at AV123 that should be saddled up to the boys down under to find a answer to our madness.
Tubby |
Rhing ..yes you are correct I did post in AV123 ...I like the power of a forum .. a group think ;)
I lucked out and bought a few of the USA Amperex's from a guy in Viet Nam , they were left there ..brand new when the US pulled out in '73 what a treasure !
off the topic I have a Musichall CD25 that I bought as a transport ..the previous owner did surgery and disabled the onboard DAC ...it works fine for me as I have a Ack dac , I have just ordered the Tentlabs X02 clock /PS so I will do that first and listen to the SP3 as is then break open the solder ...and see where it goes
will post it all ..
I have ONE other question ...has anyone had experience using new power tubes other than 6L6GC's ???...I have heard rumors of people using KT66's but only that nothing conclusive ...it is difficult to get any tech info out of AV123 re biasing voltage potential on the SP3
cheers ! |
Tubby, you won't be disappointed with the Onix XCD-99 CD player. I own the XCD-88 which is virtually the same as the XCD-99 aside from cosmetic differences. I bought a B-stock unit from AV123 as I wanted something that would match the SP3's grey metal fascia. The B-stock unit was in excellent condition when I received it and it has been very satisfying to listen to. I plan to upgrade the unit through Underwood Hi Fi in the near future as AV123 will continue to honor the three year warranty even after Underwood Hi Fi's modifications. If you want to save some more money, call AV123 and ask if they have any B-stock XCD-99 or XCD-88 units available. They back up their B-stock units with the standard three year warranty. All-in-all, this CD player matches up very well with the SP3 integrated amp for a very musical combination.
Bernard991, please keep us informed about your mod plans. I think you've posted some information about this on the AV123 forum, correct? Anyway, your post has me searching for NOS tubes 6922's and 12AU7's. |
Is all this a sign that the meek will inherit (at the least) AudioGon ?
Tubby |
if I may wade in here ....I have the SP3 also , my first impression on hearing it was "great musical midrange it has potential " my Awe-phile pal ( with a harshly critical ear ..came over and listened , he also liked the mids ...but was not too impressed w/ the rest ..
when I suggested we roll a bit ...he said 'go ahead'
I removed the Chinese 12 AX7's and inserted a pair of older ...maybe late 60's bugleboys ( Holland) ...wow what a difference , he agreed , opened up the soundstage , definetely more musical ..we continued to listen
then I suggested another change ..'go ahead' he replied
this time I swapped out the stock 6922's for a very special pair of mid 60's Amperex PQ's (USA) ..Wow again another step in the right direction ..extension in all the extremities ...that was it we made a night of it ...great presentation ..really enjoyable is how my friend put it .
a couple of days later he said to me ..here tryy these as he gave me a little packet ..inside was a pr of old stock 12AU7's also bugleboys , but this time from England
I listened to the system w/out these ...some Ella F , not too bad ..then I put in the BB's ....it amazingly smoothed out the top end , sybillance was gone ..the cymbals shimmered ...WOW
my friend who has a very expensive Atma sphere set up ...confessed that before hearing the SP 3 he was convinced he would not like it ...remarked he cannot believe the value of this unit , it has no right to sound this good at the price !
I agree & have decided to do the "full monte" ...I have ordered all the Parts connexion level 1 components ( see underwood wallys A-Gon ad for Onix ) , hexfreds , bypass caps , new RCA's , silver wire , resistors as well as teflon V caps for the pre cplg. ....I have a vision that this cute little unit can go all the way ! |
I like Telefunken, Amrpex, or BRIMAR 12AX7's When it comes to the 5881 ( 6L6 ) I'm not a big fan of the Tung-Sol. Very sweet but at the same time, to mushy for me. I prefer some of the big bottle 5881's such as the GE or RCA. But it depends on the user I guess.....
But i agree with what was said above. Try changing the 12AX7 first. |
Thank's for the help Rhing. I will give Torres Engineering a call later today. They seem to be the ONLY ones with the GT 12AX7-M's. I'm still thinking stongly about "Cyro" tubes (for the 6L6's), but they are a bit pricey. On the other hand, they last an awful long time.
My speakers are ones that the SP-3 should not be able to drive, but they do. They are the Genesis 400's. They are about 6 years old, made just before the Gennesis break-up and not continued in their new (and less conventional looking) line. They are kinda the "forgoten Genesis" (along with the 300). A tough nut to drive. Their signature is a VERY smooth and OPEN sound, with ttttight bass and silky highs (the Genny tweeter is about the best around). Drum solo's will scare the normal mortal, and some audiophiles.
We are "low level" listeners in this house, so the need for power is not a tremendous issue. The SP-3 has work out just fine so far. I think with the added benifit of rolling the tubes to match the rest of the system, it may be a perfect match (for us anyway).
The next venture is an Onix XCD-99.
Tubby |
If you are still interested in getting the Groove Tubes 12AX7-Ms, you can get a pair from Torres Engineering in San Mateo, Califoria. Their Web site is: www.torresengineering.com. Their price is very reasonable and they also carry the SED 6l6GC power tubes. I haven't rolled any other tubes with my Onix SP3 yet, but I was thinking of trying out the Electro Harmonix 6922 and 12AU7 tubes next. I might even try NOS Jan Phillips 6922s. Just curious what speakers are you using Tubby? |
In a short answer to my own question, I dropped in a pair of NOS GE 6dj8 (6922)'s in the SP-3 and found a slight but very distinct difference. The GE's (similar in sound to the Philips imho) brought out a more "single ended" immediacy with a tad more "forward" presentation. The images are a bit more localized and a bit more transparent. Not whole bunch better, but a little. Combined w/ the 12ax7wb change, it is a lot. I'm sure that cost was a factor in selecting the stock tubes for the SP-3, but in all fairness, they did choose some musical ones. The stock tubes are very open and non-fatiguing, but they are in need of a bit of speed and texture (again imho).
Tubby |
Thanks for all info. .... Valuable and appreciated.
I didn't find anyone that had any of the GT 12ax7M tubes in stock (even Groove Tube is back ordered). I did try a pair of Sovtek 12ax7WB's (that I purchased from a music store close by). "BIG" difference (lower/tighter bottom and way more open). I'm getting the feeling that these ONIX SP-3's are VERY-VERY tube sensitive. What a plus !! I have had a few amps that "tube rolling" did just about nothing at all for them. Pleasant surprize indeed.
I will take your advise on the SED 6l6's as soon as I get a new CD player in (one expence after another, isn't it). "TubeDepot.com" has the "Cryo" SED-6L6GC's for about 120.00 (a Quad). I'm thinking seriously about doing that. Haven't tried the Cryo tubes before but have heard some good things.
Have you played around with the 6dj8/6922's at all yet or the 12AU7's ? I would think that the 12AU7's would not have too much effect ( not by my experiences anyway) but a NOS (or better than "stock") set of 6DJ8s might... I don't want to roll all the tubes at once but I am a bit anxious to hear "all" of this "little jewel" of an amp.
Tubby |
Tubby:
Check out this thread:
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1143225993&read&keyw&zzonix
Before you touch the 5881 tubes (which are basically the military version of the 6L6) in your new Onix SP3, do yourself a favor and install a pair of the Groove Tubes 12AX7-M "Mullard Reissues." You'll find the bass to better defined and the mids livelier without giving anything up in terms of detail and speed. The Chinese stock 5881s are decent, and you can get more mileage out of changing the 12AX7 preamp tubes.
If you have the itch to change the four power tubes, get a matched quad of the SED "Flying C" 6L6GC tubes, and adjust the bias of the tubes accordingly. |
The only 5881's I heard were Sovtek's so I can't judge. However, somewhere I read that your amp would take 6l6gc's. If that is so I would recommend the SED 6l6gc. Its a great tube, especially thru the mid range. |
I like the old stock Tung-Sol 5881's.
That being said, I've not tested that tube type in several years. |
