Tube DIY Asylum: Re: Facts, etc. by cheap-Jack

Hi Gary.

Thanks for your info on 6CJ3 which is pretty cheap to buy.
I read the Amity HV power supply circuit which is full wave rectification using 2 x 6CJ3. Can I use just one for half wave?

Building tube amps without power transformers? I have had years' experience in it. One of my DIY triode SET amp I am using is a no-power-transformer design, with 1.5-watt output per channnel. Not much power but it sounds fine to my very picky ears.

Again Gary, you missed my point. I said all iron goods got their own sonic signatures, cheap ones even worse. That's why Sakuma-san needs to specify only one make of irons to ensure getting the sound he likes. Likewise, Lynn specifies the make he finds fit for his sonic requirement. I never said or even hinted Lynn needs to follow Takuma-san, or whoever's pattern of design or use of parts!

Me too, I like vibrant & powerful, but also detailed, transparent, & neutral sound. I have auditioned so many hi-end brandnames in the past, & I believe only all-triode OTL-OCL design can deliver ALL these virtues.

SET is fine but in most situation, lacking the muscle to deliver forceful climaxes, like Beethoven's & Mahler's complex symphonic works, or over 100-dB SPL heart-throbbing pop band music, like Michel Jonez's "Le temp passe" (a pretty popular demo CD used in many audio boutiques.) I tried so many SET brandnames, which crapped right out with demanding music at live levels.

I have spent enough time in reserach for 'my' amps commercially available in the market which fits my design philosophy - straight line concept. Eventually, I have come to my conclusion: all-triode OTL-OCL power amp. I auditioned the makes like GRAAF of Italy, Atma-Sphere of USA, which builds & sells 'Hall-of-the-Fame' & awards winning OTL-OCL tube-only amps for the last 25 years, & the latest contender: Tenor Audio of Canada.

The winner is? Tenor 75WI 75-watt OTL-OCL monoblock (retailed for 'just' USD20,000 a stereo pair). When mated with Hyperions speakers, a 6-ft tall 550-lb fiberglass 'monster', individually handcrafted by Rockport Technologies of USA (retailed for 'only' USD85,000 a pair!), this combination won the "Best Stereo System" nomination by a critic of the Absolute Sound journal in its July 2002 issue.

I spent a few afternoons listening to these set-up in their distributor's demo room & I had to find back my jaw where I dropped it - bigtime! So lifelike & real, & yet so tender & detailed!

After this unforgettable sonic experience, I started to search for the right circuit for my new DIY all-triode OTL-OCL project, which, unlike SET designs, is popular only in Japan. Thanks to the invaluable insight of John Broskie, owner & designer of GlassWare Audio Design Software, I have completed the circuit of my 40-watt all-triode OTL-OCL monoblock, basing on Futterman's variation.

The output power tubes will be 2x6C33B-C, the same output tubes used by Tenor 75WI (which used 4 tubes)! I am now 'simplifying' its HV & LV power circuits to go without power transformer, hopefully! There will be a solidstate HV shunt regulator for the Mullard 12AU7 driver stages, & switch-on time delay + speaker protection circuit, too. Well, let see.

That is what I say new millennium audio technology applied to century-old tube traditions. This does no way affect my obsession of clssical
music enjoyment from my hundreds-of-LPs collection.

Good listening & thanks again.

cheap-Jack
Sept 17, 2003.