I can't imagine the harshness you describe is coming from your Audible Illusions preamp. The best person to talk with regarding tubes for your preamp is Art Ferris, the guy that designed it.
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Well ... harsh may not be the right word, but maybe due to some of the recording, some song has very strong glare ... I don't know if it is the right word also. Usually when hearing female vocals. The bottom line is, got fatigue after hearing for a while. Some recordings are ok. Anyway ... just want to try out some other tube to see if it will improve the sound to my taste.
You could try older 6h23eb (the ones with the rocket logo) if they are still around. They are a bit softer sounding than the ones made @ Refektor (sp).
I used Siemens 7dj8 in the phono section of a Mod 3a, but never tried them in the line section. Maybe someone here has?
The 7dj8 was durable in the application and had a nice smooth/liquid sound (akin to old production Mullard and Amperex 6dj8's).
You will get much smoother sound with NOS 6922 like Amperex etc. As you are probably aware however, these preamps are tough on tubes and it is not cost effective having to replace NOS tubes every 6-12 months.You might consider some Herbie's Audio Labs tube halos and some different footers. These tweaks can smooth the sound out some.
Thanks. I am reading Joe's tube Lore page. He also recommend the Amperex white label PQ 6922. I found a couple posting on eBay, but it is not matched pair and are expensive, average to be $180. =(
I am very new to tube. So, all those Amperex tubes are old, and can only get from eBay? I tried search the tube store, but can't see any of them.
I am reading Joe's tube Lore page. He also recommend the Amperex white label PQ 6922. I found a couple posting on eBay, but it is not matched pair and are expensive, average to be $180. =(
Not for the AI
Special warning to Audible Illusions preamp users:http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html#6DJ8
I am very confused. So, the Amperex 6922 is not good? From the AI FAQ, it says:
"Only "mil-spec, low-noise" 6922, 6DJ8, 7308 or European E88CC tubes are recommended for use in Modulus preamplifiers.
Previous production Modulus M2, M3, M3a and L1 preamplifiers used Russian 6922 tubes. While quality and sonic performance of these tubes were excellent for several years it is unfortunate that current-production from the Sovtec/Reflector factory does not have the same sonic identity and a high percentage prematurely fail.
Current production Modulus M3a and L2 Preamplifiers use a Russian Military Type 6922 with "Grey Plates" and have excellent sonics and reliability.
Similar tubes which have different technical specs should not be used.
7DJ8 tubes require higher filament voltage and performance is marginal.
6NIP tubes should not be substituted as they require additional filament current and their use will compromise performance."
So, the 7D8J and 6N1P conflict with Joe's comment. And Joe said 6922 is not suitable? ... So, the remaining choice are:
6h23n, 6DJ8, 7308, E288CC ?
Previous production Modulus M2, M3, M3a and L1 preamplifiers used Russian 6922 tubes.
You have the L1 correct?
09-24-10: AudioconnectionSounds like good advice.
09-24-10: ThedukeAlso good advice
A good rugged tube.
The 6DJ8, 6922 and 7308 are a family of tubes that are interchangeable in most audio applications. The E88CC is the European name for the 6922. The 7DJ8 is a little higher voltage version of the 6DJ8. Unfortunately NOS versions of these tubes are expensive and will probably not last very long in your preamp.
This discussion is only going to get more confusing. Get in touch with one of the tube sellers recommended here or in other threads and take his advice. That is the cheapest and easiest way for you to find tubes that will give you the best sound you can get at a price you can afford.
thanks for the advice. I will try turn on the cap. It is currently turn off based on recommendation from AI. It won't hurt to try turn it back on. Actually, what is that cap thing?
Also, the Electro-Harmonix-6922 seems worth a try. Not expensive, and it says it may help to remove some of the harshness.
My friend came over and he have a better word to describe other than harsh. It is "dry". It is hard to describe, but when he said this word, I feel it describes the sound.
I have been using an L1 for the past 3 years and currently have the 6h23neb tubes installed and they sound fine to me. I have had them installed for about a year. Before that, when I bought my L1 it came with RCA brand 6DJ8 tubes (made in Germany)which were supposedly made by Siemens in the 60's or 70's. I changed them after 2 years of listening (a lot)just to try something different. I really can't say one is better than the other but they both sound great to me.
Some people on these forums like to indicate that any and all preamps made by AI eat tubes. In my case I certainly haven't found that to be the case so yours may be like mine and not go through tubes.
When you say the sound is dry, I'm surprised no one asked what source, amplifier, and speakers you were using as this could make a lot of difference. One thing about the AI preamps that is different from many others is the fact that they are phase inverting. This means (according to the AI owners manual)that you should switch the red and black speaker cables at your speakers so the red cable is connected to black speaker connector and the black cable is connected to the red speaker connector. Doing this may help but only do it with everything turned off so you don't inadvertantly touch them together and damage you amplifier.
I assume you don't have an owners manual for your preamp. I bought one from AI after I bought my L1 and it took F O R E V E R to get it. If you would like a copy, send me an e-mail with your mailing address and I will send you a copy. It's pretty simple and may help answer some of your questions.
Only tried 7dj8's in the phono section (1983 Reflektor 6h23's were used in the line stage).
The phono was more open/liquid sounding with 7dj8's VS 6h23's.
Someone in the forums suggested this combo/placement.
Try searching here and @ audioasylum to see if anyone is using 7dj8's in an L1, or in the line section of a 3 or 3A.
If so, I would go with the Euro Philips @ Upscale as the price is OK and they are smoother sounding than Siemens, and Tunsram.
I tried Telefunken 7dj8 as well, but suspect they were not good examples of the tube.
What amp and cd player speakers are you using
the dip switches for Caps on should sound more neutral
have you done this yet?
Its easy don't worry you cant hurt anything
just mute the pre amp when you do it
Did you invert both speakers Plus with the Minus as in the manual?
Please let us know what you hear.
Try using the "Aux" input and see if you can hear a difference. I think the other inputs have a series resistor in the signal path.
You might also want to try "Main Out #2" which has a 470 ohm resistor in series. To quote the manual "This corrects for anomalies i.e., tube "glare" that are exhibited in some brands of tubes. If you are running a long length (over 15 feet) of interconnect, it is best to use Main Out #1"
I use the "Aux" input for CDs, "Main Out #1", and the capacitor DIP switches are set to OFF.
I currently have a pair of 6H23P-EB tubes that Upscale Audio calls "Type 3" that sound really nice. I've also used a pair of Matsushita 6DJ8 that sounded pretty good that I bought from Andy at Vintage Tube Services.
Of course, what you are hearing might be a system matching issue.
Here is my system:
Sony Blu ray player, Maverick audio DAC (not using the tube buffer), AI L1 preamp, McCormack DNA-1 deluxe amp, B&W CDM9NT speaker.
I am using the Aux input, and Main 1 output. I will try using the Main 2 to see if there is any different.
Also, I have the speaker wire inverted. I have the caps turn off before as recommended by many others. I tried to switch them on last night. I agree that it is more neutral and easier on ears. I will try turning it back on and Main out 2 to see who it sound.
I tried different combination.
Caps on with Main 1 out - harsh or dry
Caps off with Main 1 out - sounds thin, less musical, but easier on listening
Caps on with Main 2 out - it seems it improves the situation a bit, not as harsh. Or according to the manual, it removes tube glare.
I prefer to have caps on and Main 2.
Per the previous owner, the tube is Russia military grade 6h23neb with less than 50 hrs.
I also tried switching the left and right tube, but the buzzing noise is still louder on the left channel, so, it is not because of the tube. It is not a big deal, can't hear it at the sofa.
I am egar to try out the 6922 and see how it sound.
Thanks for the advice. I don't think it is because of the interconnect though. I got the noise since the first day I got this preamp, then I upgrade the interconnect, and the noise is still there. Maybe some capacitor are old? Inside, there is a sticker says it is checked in 96. So, it is a 14 years unit. Is it about time to have a service and replace some capacitor?
I did some more listening, the Main 2 out seems work for me. It remains musical with good sound stage, and the harshness or glare is improved.
I have had L-1 for about 7 years. One day the tubes went bad it made a harsh static kind of sound. I replaced the tubes and all was fine. On the Audible Illusions site they recommend tubes to use and not use. I had a set of brand new Svetlana tubes which I used. I then went on ebay and got some cheap mullards. When I replaced the Svetlana tubes with the Mullard tubes there was a noticeable increase in fullness and base. Also I notice that the highs were less fatiging
I tried plug and unplug several times, and it is still there. And it is not intermittent anymore, it is a continuous hissing sound. I also switch the left and right tube, and the hissing sound move with the tube. By this, I can confirm one of the tube failed. The other is still ok. So, usually, a tube won't fail this fast, is this covered under any warranty?