|
Home | Forums | Rules | Articles | diyAudio Store | Blogs | Gallery | Wiki | Register | Donations | FAQ | Calendar | Search | Today's Posts | Mark Forums Read | Search |
Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum |
|
Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving |
![]() |
|
Thread Tools | Search this Thread |
![]() |
#1 |
diyAudio Member
Join Date: Feb 2005
|
![]()
I have gotten an old AI dual mono preamplifier which was i think the very first preamp from AI designed by Mr. Bruce Moore. My problem is that in the absence of manuals, I cannot distinguish as to which tubes are to be installed where. Checking the AI site made me more confused as the history says the AI dual mono has only 3 tubes per channel (1-12AX7 and 2-6DJ8). Mine has 4 tubes per channel. AI technical page right here:
http://www.audibleillusions.com/tech...PREAMP_HISTORY I have already contacted AI but I do not have answers from them yet. Ill appreciate kind folks out here who can direct me to where I can purchase a copy of the manual or a tube placement diagram. I hope there are other AI dual mono owners here too. Thanks. |
![]() |
![]() |
#2 |
diyAudio Member
Join Date: Dec 2003
Location: The Wilds Of Canada
|
12ax7 TEND to be phono pre, as a pair, in Mr. Moore's designs, and the 6DJ8's TEND to be the 'drive' or output section. So the ones near the phono inputs are likely the12ax7 pair and the the others, well, the others. the 6DJ8 positions. These are the overall, standard application for these tube types.
Can you follow the wiring at all? If I had to guess, and being wrong would be death (as in a gun to my head) I would unhesitatingly go for the above mentioned scenario. If the above AA unit came with tubes in it, and is functioning, then the look of the innards of the tubes will make it excruciatingly simple! Simply compare..or... Go to 'the tube store' and select 12ax7, and then 6dj8 tubes, and you will note that in the pictures of the innards, they are strikingly different. This is generic to the tube type, not the brand. A 12ax7 will always look like the ones in the photos, and the 6dj8, will always look like the ones in the photos.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan. Sometimes the claims aren't extraordinary. Sometimes the weakness of men's minds are the culprit. Mass mentality has nothing to do with obviousness or truths. |
![]() |
![]() |
#3 |
diyAudio Member
Join Date: Feb 2005
|
the pre is functioning alright. the tubes installed is 1-12AX7 and 1 unidentified tube not similar to a 12AX7. These 2 I am sure are for the phonostage. The linestage tubes was 1-7308 (which looks like a 7199) and another 7199. This brings the total number of tubes of my AI pre to 4 per channel. Whilst Im sure the arrangement is similar to what you have outlined, I still want to have a copy of the manual and verify. Thanks KBK for that input of yours. appreciate it.
|
![]() |
![]() |
#4 |
diyAudio Member
Join Date: Dec 2003
Location: The Wilds Of Canada
|
Moore has some designs using a 12AT7 as a buffer on the output of the phono section, which is usually 12AX7 type tubes. This is similar to the Magus series of MFA preamps.
The 12AT7 has innards similar to the 12ax7, but are smaller. It could also be 6An8 tubes in use, which look similar to the 7199. also, it could be ..I'm trying to remember 6EU7, I think, which was in the old heathkit preamps. Little triode-pentode tubes. Pin arrangement can be assayed, compared to the spec for these three different tubes, and then it can be figured out what tube is what.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan. Sometimes the claims aren't extraordinary. Sometimes the weakness of men's minds are the culprit. Mass mentality has nothing to do with obviousness or truths. |
![]() |
![]() |
#5 |
diyAudio Member
Join Date: Feb 2005
|
thanks KBK. will certainly evaluate those tubes
|
![]() |
![]() |
#6 |
diyAudio Member
Join Date: Oct 2009
|
Hello.I´bought one AI m3(is not new).It´s broken.It´not original.sam compoment is changet.I need the electrical circuit to repair.Sorry my inglish is bad.thanks
|
![]() |
![]() |
#7 |
diyAudio Member
Join Date: Jan 2010
Location: auckland
|
You can fix the amp first then fix the english later when able. lol. I'm just kidding. Hope its fixed now hence you've posted 2 yrs ago.. cheers
|
![]() |
![]() |
Thread Tools | Search this Thread |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Reducing gain on Audible Illusions M3A | no xo | Tubes / Valves | 4 | 27th August 2007 05:27 PM |
Audible Illusions Modulus faulty? | st2_998 | Tubes / Valves | 4 | 25th August 2007 02:20 PM |
audible illusions dual mono preamp | firecox | Tubes / Valves | 4 | 28th December 2006 08:46 AM |
input caps in an Audible Illusions M3 | funnyjoe | Digital Source | 0 | 24th October 2004 05:58 AM |
60 Hz noise in modified Audible Illusions M2B | mas | Tubes / Valves | 1 | 14th May 2004 03:59 PM |
New To Site? | Need Help? |