What tubes doe the Audible Illusions Mod 3 use?

[JPM]

I have the Mod 3 that was stashed away but I want to use it again. The tubes need to be replaced but what tubes do they use? Also 'phase inversion', I hear you should invert the phase, what does that mean? Many thanks.:exciting:

 

[joeinid]

If you can open it up and look at the tubes that would help, but if I remember correctly it has four 6DJ8/6922 tubes—two for the phono section and two for the line-stage.

http://www.audibleillusions.com/products/l3-line-stage-preamplifier/l3-linestage-specifications/

http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/6H23n-EB-6922

L3A TECHNICAL SPECIFICATIONS

Gain: 30dB, Tape & S/S Processor 0dB
Distortion: .10% at 1.5V rms, 20-20kHz, into 50kOhm. Less than .12% at 1V out 20-20kHz into IHF load
Frequency Response: Within +/-1dB 2Hz to 100kHz measured w 1-1 probe/50 kOhms,100pf
Signal to Noise: 90dB below 1.5V rms output wideband
Max Input: 9V rms
Signal Phase: Main Out-Inverting, Tape and S/S Processor-Non Inverting
Input Impedance: 50kOhm – all
Output Impedance: Main-1.2 kOhms Tape, S/S Processor-150 Ohms
Muting: 45 second warm-up and automatic brown-out protection
Tube Compliment: 2-6H23EB twin-triodes, graded & matched
Power Requirements: 115-125VAC, 60Hz 45 watt maximum. 6 foot IEC Line Cord-Supplied.
Optional 100, 220, 230, 240 50-60Hz transformers.
Dimensions: 19″W x 3.5″H standard rack mount
Chassis is 17″W x 11″D x 3″H
Power Supply, 6″W x 10″D x 5″H
Weight: 19.5 lbs, 24 lbs (shipping wt.)

 

[Jack]

The Audible Illusions earlier preamps were notoriously hard on tubes so the recommended tube for them is usually the Russian 6h23-EB.
Most of the earlier stock from the 60-70's pretty much gone unless you get lucky on Ebay.

http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/6H23n-EB-6922

 

[audio.bill]

Joe is correct on the tube compliment. One piece of advice I can offer you from first hand experience with several versions of AI Modulus preamps is that the circuit used is VERY hard on tubes. Many varieties of fine quality tubes will sound fine for a short time but often then become noisy and/or microphonic. They're known for that, and as such many tube sellers won't even sell their tubes to users of AI Modulus preamps and specify such in their listings. So be careful with your selection of tubes and hopefully get advice from the seller of a specific brand that is known to be well suited for use in that specific preamp. They do sound good though and provide a real value when matched with appropriate tubes.

 

[joeinid]

The NOS 6H23P-EB (Premium) tube is a very noticeable upgrade over the Sovtek 6922 tube and Electro Harmonix 6922 tube. They are incredibly durable and can handle the punishment of modern pre-amps, including those made by Audible Illusions. They excel in detail, speed, and soundstage. The highs have air and sound natural.

This premium Russian built NOS 6922 tube replacement is also known by various Russian names, including 6N23n-EB, 6H23N-EB and 6N23. These are the hard to find NOS (new old stock) of premium quality in both sound and construction.

The 6922 / 6DJ8 tube type is equivalent to the European ECC88 / E88CC tube and can be used in any 6922, 6DJ8 or ECC88 circuit.

 

[Jack]

JPM

This may be just about as good a deal as you will find on these tubes from a US based seller.

http://www.ebay.com/itm/NOS-6H23-6N...306570?hash=item440185904a:g:GkgAAOSwHptY~4zf

What amp are you going to match the AI with?

 

[JPM]

The preamp is the Audible Illusions Mod 3A which I believe is their last model. I will be putting it on my VTL Renaissance S 70/70 to my Spendor SP 100s speakers.

 

[gareneau]

JPM
From Dick Olsher's review of the L3A in 2016:

Then, in the mid-1980s, Art discovered the Russian 6H23n-EB, really a premium version of the 6922. Not only is it a good-sounding triode, but it also happens to be rugged, exceptionally linear, low in microphonics, and, according to Art, very stable in his zero-feedback tube designs. Subsequently, all of AI’s Series 3 preamps since 1989 have this Russian tube installed in the linestage. Note that AI no longer recommends Russian-branded (e.g., Sovtek) 6922s due to poor quality control. AI will continue to use NOS Russian-military 6H23n-EB tubes until AI’s Russian distributor can no longer supply them, at which time Art says he will probably switch to the Russian 6H30 tube.

If I read Dick right, the NOS Russian-military 6H23n-EB tubes are STOCK in the AI gear (since 1989), so I'm not understanding recommendations here to look for them to do some tube rolling.

 

[joeinid]

Welcome to the forum gareneau, thank you for joining.

 

[gareneau]

Happy to be here, Joe, and thanks for the nice greeting. Do I have it right, that the tube rolling recommendation is moot as the 6H23n-EB tube comes as stock? Or am I missing something? I own the AI M3B and am looking to get a little more emotion out of the preamp, consequently my interest in the thread.

 

[joeinid]

Happy to have you here.

According to the website, Tube Compliment: 2-6H23EB twin-triodes, graded & matched, come standard. I hope someone else will join in and make any recommendations for substitutes. I think you don't have many options as the preamp seems hard on tubes.

Happy to be here, Joe, and thanks for the nice greeting. Do I have it right, that the tube rolling recommendation is moot as the 6H23n-EB tube comes as stock? Or am I missing something? I own the AI M3B and am looking to get a little more emotion out of the preamp, consequently my interest in the thread.

 

[Stoutblock]

Mullard CV2493 tubes if you can find them and/or afford them. About the toughest/sound quality 6DJ8/6922/7308 tube I have ever found.