2. amps-preamps
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300b lovers

I have been an owner of Don Sachs gear since he began, and he modified all my HK Citation gear before he came out with his own creations.  I bought a Willsenton 300b integrated amp and was smitten with the sound of it, inexpensive as it is.  Don told me that he was designing a 300b amp with the legendary Lynn Olson and lo and behold, I got one of his early pair of pre-production mono-blocks recently, driving Spatial Audio M5 Triode Masters.  

Now with a week on the amp, I am eager to say that these 300b amps are simply sensational, creating a sound that brings the musicians right into my listening room with a palpable presence.  They create the most open vidid presentation to the music -- they are neither warm nor cool, just uncannily true to the source of the music.  They replace his excellent Kootai KT88 which I was dubious about being bettered by anything, but these amps are just outstanding.  Don is nearing production of a successor to his highly regard DS2 preamp, which also will have a  unique circuitry to mate with his 300b monos via XLR connections.  Don explained the sonic benefits of this design and it went over my head, but clearly these designs are well though out.. my ears confirm it. 

I have been an audiophile for nearly 50 years having had a boatload of electronics during that time, but I personally have never heard such a realistic presentation to my music as I am hearing with these 300b monos in my system.  300b tubes lend themselves to realistic music reproduction as my Willsenton 300b integrated amps informed me, but Don's 300b amps are in a entirely different realm.  Of course, 300b amps favor efficient speakers so carefully component matching is paramount.

Don is working out a business arrangement to have his electronics built by an American audio firm so they will soon be more widely available to the public.  Don will be attending the Seattle Audio Show in June in the Spatial Audio room where the speakers will be driven by his 300b monos and his preamp, with digital conversion with the outstanding Lampizator Pacific tube DAC.  I will be there to hear what I expect to be an outstanding sonic presentation.  

To allay any questions about the cost of Don's 300b mono, I do not have an answer. 

 

 

whitestix
lynn_olson's avatar
lynn_olson
405 posts
 

Good, although brief, discussion of the 6EM7 on Thomas Meyers’s Vinyl Savor page. It looks like a TV tube, not designed for audio, so NOS examples might be somewhat variable (the application in the deflection circuits of a TV would only have moderate requirements for linearity).

No current production for obvious reasons ... vacuum tube TVs disappeared fifty-five years ago, along with the tubes that went into them. But there’s probably plenty of old stock.

Analog vacuum-tube TV’s, particularly the inexpensive B&W models, had pretty bad picture geometry. Once integrated circuits took over in the early Seventies, picture geometry got a lot better, and all of the many different service adjustments went away. NTSC and PAL color TV is a lot easier when all the complex signal processing is inside a single chip, instead of several tubes with many adjustments.

Collectors prize old 21" round-tube color TVs (1955 to 1967 vintage), but they are not easy to keep running (with many adjustments and 26 to 28 hot-running tubes) and CRT refurbishing services went out of business about ten years ago.

Would I use a TV-only part in a new design? No, I would not. Zero chance of LinLai or JJ putting it back in production.

lynn_olson's avatar
lynn_olson
405 posts
 

The tube Don, myself, and many other manufacturers would like to see go back in production would be a 45. NOS examples are astronomically expensive now, and surely production costs would be similar to, or less than, a 2A3. It’s basically a very simple tube, unlike a 6SN7 or a 6EM7, although "simple" is still plenty expensive relative to capacitor or transformer manufacturing.

In the meantime, we’ll be using triode-connected 6V6’s, which operate in the same power range as a 45 (275 volts at 32 mA = 8.8 watts), have the same (triode-connected) Rp = 1800 ohms, and have excellent performance. Many choices with NOS and current production.

Vacuum Tube Valley on the 6V6

45 Datasheet

 

lynn_olson's avatar
lynn_olson
405 posts
 

Good read on the 6L6, designed by the RCA team that also created the 6V6 a year later.

Vacuum Tube Valley on the 6L6

And of course the 45

Vacuum Tube Valley on the 45

 

charles1dad's avatar
charles1dad
10,250 posts
 

Thanks @lynn_olson

Here is a bit of information/listening impressions of the Roger Modjeski 6EM7 amplifier from a past Audio Circle thread.

https://www.audiocircle.com/index.php?topic=29587.0
Charles

donsachs's avatar
donsachs
309 posts
 

@charles1dad

I am sure it is a great amp.   Looks like my usual sources have 6EM7 for $15 a tube or so.  If you love the amp, you probably already have bought a few for the drawer.  If run conservatively I would expect them to last a long time, so a few spares will set you up for many years of listening.   As Lynn said, I just cannot design an amp around extinct tubes.   The exception are the various damper diodes and gas VR tubes.   But there are tons of these out there for under $10 each and they last many years.   When we ramp things up we will source a mass buy.   It is always risky to design gear around extinct tubes... a delicate dance.  You certainly don't use rare tubes.   I think your 6EM7 is reasonably available so you should be good for years. 

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