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
donsachs's avatar
donsachs
282 posts
 

Yes, these amps sound very good after 10-15 minutes and are very consistent.  They sound the same every day.  I have the preamp and amps plugged into a Puritan supply, which does clean up grunge in the AC line.   Basically, you turn them on and they sound quite good as soon as they can play music in 30 secs or so, but in 15 minutes or so the tubes are all warm and then they are pretty much on song until you turn them off.  They may sound a wee bit better after 30+ minutes, but really 15 gets you almost all of it.  Plus they run quite cool.  You can leave your hand on the transformers or anywhere on the top panel even after the amps have been on for an hour.  No, it is not a class D amp that barely warms, but they run quite cool for a class A tube amp.

 

donsachs's avatar
donsachs
282 posts
 

This has been an interesting thread.  I didn't start it, nor did I expect it to have this long a life.  It is very clear that there are many ways to build amps and preamps.  I just want to restate my goal for this project.  I am semi-retired.  I wanted to build the best sounding preamp and amp combination that I could.  A setup that I can happily listen to the rest of my days and that will drive a reasonable subset of the speakers out there.   Within reason, I didn't care at all what it cost.  Once done it will be produced by a partner and priced according to what it actually costs to build plus enough to cover their labor and margin to stay in business.  It will be sold directly to customers though with no distributor markup.  But it costs what it costs to build because the main goal of the project was to produce the best sounding preamp and amp that was possible without have some four chassis amp or gold plated case and $50,000 starting point.  The thread has shown why we made the design choices we did and where it led us based on a combined (gasp) probably 70 years of experience with amplifier design and builds between Lynn and I.  He is the historian as well, and I have rebuilt literally hundreds upon hundreds of pieces of classic tube gear, so I guess that makes me sort of a hands on historian.  

At any rate, I thank everyone for their civility and free discussion of audio ideas that has made the thread enjoyable.  I hope to meet a few more of you next year at the Pacific Audio Fest when I will be there with actually production versions of these for you to hear.  Trust me, they are FAR better than the prototypes shown this past June.

gladmo's avatar
gladmo
363 posts
 

I want one

donsachs's avatar
donsachs
282 posts
 

@gladmo

Spatial Audio Lab will be making the amps and preamp.  All parts are ordered and I hope to be going to Salt Lake City in early November to train them on the builds:

https://www.spatialaudiolab.com/news/september-2023-update

If you have interest, then contact them.

 

stephenr
8 posts
 

I’ve been following … no … have been massively influenced by Lynn’s Karna amplifier and the reasons behind the topology. My first effort is on Lynn’s site as the PP813 Grand Aurora so I’ve been at this for about 20 years.

It has now morphed into all DHT with finals of GM70 so not part of the discussion in a 300B thread.

These types of amplifier are not easy to get right. Even though the signal path is ridiculously simple, it is still challenging and the supporting power supplies are anything but easy. Finally after all this time, I’ve succeeded in getting to the sound I was after.

Probably as I’m not in the position to commission a super IT and maybe as my current one is not so super, I’ve ended up DC coupling the 1st to the 2nd stage in a similar way to Kevin Carter’s method; choke loaded 1st stage.

Don mentions in the thread DC coupling was not an option for a commercial product, but I’m left wondering, was this method evaluated in the many permutations of coupling configurations for the front end?

I’ve also got a line stage, which again, is heavily influenced by Lynn’s designs; the Raven but using 12B4; initially used as a headphone amplifier. The system is better for it being in the chain than out despite having no gain.

Many thanks to Lynn for providing oodles of thought-provoking posts over the years to fuel the ideas leading to the success I’ve had.

 

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