I nestled the power transformer behind the existing power switch, after relocating a few circuit boards.

The transformer was fastened to the chassis with one 6MM bolt thru the bottom.

To fit the tube output board, I had to remove the video portion of the player. This was not a problem for me as I use the unit for CD playback only.

An aluminum plate was fabricated to mount to (4) newly vacant mounting tabs….in turn, the board was bolted to that plate.

The output signals were taken to a pair of chassis mounted RCA jacks installed into some unused holes.

The sound is very good! Smooth, extended frequency response, and very musical….MUCH better than stock!

The build is finished and the sound is great.

I will let you know how it sounds once it has run in for a while but at this stage the improvement is quite staggering.

The build was fairly easy though my shaky hands didn’t make soldering to the dac chip outputs very easy

I am now using gilded copper rca’s and solid core mono crystal copper cabling on input and outputs which came from DIY Hi-fi SUPPLY along with the UVOS.

The UVOS, doesn’t come with a tube. After a bit of reading I chose a NOS , JAN , Sylvannia 6922 for $40 including testing for low noise and mircophony from Tube Depot.

I mounted the UVOS on nylon standoffs figuring they would provide a bit more isolation from vibration for the tube than the metal equivalents.

With about 30 hrs of the suggested 50-100hrs for the valve output stage here are some impressions.

It is rather difficult to make concrete conclusions about the performance of this new addition as I keep getting drawn into the music.That it out perfroms the opa627 based opamp output stage is an absolute no brainer and I would therefore recommend that anyone who doesn’t want to go down the transformer output route should seriously consider this as an option , particularly if your current set-up leans towards the clinical.

The sound of my system is now just more listenable and for that matter much more ‘musical’.Pace rhythm and timing are greatly improved but not at the expense of tonality , timbre and dynamics : all of which have improved by a very noticeable margin.

I am now able to play a larger range of discs without wincing so much at the less than stellar recordings.In fact previously unlistenable pop recordings are now fun and the good recordings are imho jaw dropping.

Some other bits: The quality of the board is great : soldering is immaculate , with all the components well spaced.I had a few questions on the board and the supplier replied within minutes with extensive and simply worded explanations.

Even those who bought the encased dac should consider this add-on as it could be easily fabricated into a second box or even mounted atop the original case with some form of protective cover.

Highly recommended .

Gordon

Introduction

You may remember the Chazz. It used EL34/KT88 and 6SN7 (earlier versions 6SL7) and output transformers. Eventually we sold out and it was right at the time when chassis and transformer parts costs were escalating; our attentions were diverted to reworking our whole lineup to work within the new economic realities.

The Chazz2 makes it own statement. You be the judge: OTL through film caps. MUCH much better clarity, finesse and speed as compared to electrolytics.

Main charateristics

(1) Anode vs cathode sound

Dual Outputs on the front panel:

One takes from the anode and the other from the cathode. The circuit is patented and allows this little trick. It allows you to experience the difference between anode and cathode sound. You can also drive with both (two headsets) at the same time. But feel don’t fight over who gets the anode and who gets the cathode!

(2) True balanced-modeNew!

We now have a pure copper served with teflon cable which allows true balanced-mode and includes the HD600-type connectors for plug-in operation. It is a worthwhile difference.

Simply put: hot/cold conductor takes signal from the anode and cathode of the tube. You can still select local feedback level but as one headphone set uses both outputs, only one headset can be driven at a time in balanced mode. It runs true balanced. Only the screen is connected to the phono plug body but signal is totally floating and never touches ground.

Also we configured a set of phono cables with RCA ends so the Chazz2 can also be used a a very beefy (and quiet) linestage to drive your big system. And still allows switching between anode/cathode feed and 0/3/6dB feedback. FUN! Allows voicing your hifi system. So: headamp extraordinaire, 2 x single ended or 1 x balanced mode with included cable, AND linestage. Wow!

(3) Adjustable feedback

Front panel selector toggles 0/-3/-6dB feedback.

A comparison is VERY interesting!

You choose the flavour you like.

(4) Good for money tubes*

6AS7/6080/6N13 power tube. close to unity gain and low output impedance make this ideal for headphone amplifier. A proven favourite with OTL users too. In good supply and low cost.

* 12AU7 x 2. We all know this tube. Easy rolling and sound meshes very well with the 6AS7. It gives more gain but the reason is distortion is 10x less with 2 x 12AU7 vs 1 pc of 12AX7. The difference is noticeable to those with a taste for the high end.

(5) Solid chassisThe Chassis is made of 4mm thick chassis and 7mm thick faceplate.

(6) CARBON attenuatorWe use carbon attenuator because we don’t like plastic in between us and the music. We are a carbon-based lifeform.

Package includes:

• 1 pc Chazz2 (available 110v or 230v)
• 1 pc 6SA7
• 2 pcs 12AU7
  Cable or headphone is NOT included but balanced cable can be purchased separately.

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Filament voltage, filament current, plate voltage etc for the following TJ Fullmusic tubes:

Where to find reasonably priced large value caps for the 300B WE connection? In the audio world there are not so many low cost high quality film caps. The ones commonly available are a little edgy sounding, adding a hiss, and a sing along with the music due to loose windings, voids, or poor quality films etc.

At 2004 Electronica Asia we met a rep from the 5th largest cap manufacturer in Asia. They had new production machinery from Italy, and Germany, in a spotlessly clean environment. The company was sympathetic to our audio cap issues. Samples were made with extra tight winding, no voids and thick coated aluminum film imported from Germany.

Obbligato Capacitor was then born.

Factory Background

The TJ factory in Tianjan province manufactures WE replicas with a few interesting and creative variations. 300B tubes are available as ST or Globe style with the Globe offering both solid and mesh-style (perforated) anode. The factory is a private enterprise (no state involvement) and the owner, Mr. Liu is a veteran of the tube industry having worked for many years in the Beijing Tube Factory. He graduated from university in 1955 in the field of vacuum tube technology and holds a number of QC patents in that field. He has previously produced CRTs for NEC. The TJ name is quite new to the West but has a well established following and solid reputation amongst audiophiles in Japan.

2003 Tianjin Tube Factory Tour

Apr 2003, in the midst of the SARS epidemic, saw me on a plane to Beijing and from there 1hr by car to Tianjin. Transportation provided by Opera/Consonance. Liu of Opera (not to be confused with Mr Liu of TJ tube factory) came along as tour guide. Mr Liu met us and we got straight down to business the usual way in China: lunch. The visit started with a meal at a famous Tianjin seafood restaurant. Fish steaks braised in Coke (the drink) is Tianjin’s signature dish. The city is on the northern coast of China. People in this place are super-friendly, a trait of the Tianjin populace according to Liu.
Then on to the factory, a new facility since last summer. We were required to wear plastic booties since everything is super clean. We started in Mr Liu’s office where he has a display of his creations. The factory is a private enterprise (no state involvement) and the owner, Mr. Liu is a veteran of the tube industry having worked many years for the Beijing Tube Factory. He graduated from university in 1955 in the field of vacuum tube technology and holds a number of QC patents in that field. He has previously produced CRTs for NEC. Last October he visited my office in Hong Kong and I showed him a 6N11 military tube that is known locally to be an excellent sounding equivalent to a 6922. He was quite excited to tell us that the tube was his creation for the military, the only true frame grid made in China and one of the most difficult tubes he ever put into production at BJ tube factory. The factory is smallish with about a dozen workers, most of whom are old, highly skilled workers from the tube industry. The specialized machines you see in the pictures were made by Mr Liu. A sample of the products coming out of the factory. Up until now there has been a WE flavour to the lineup but if you look closely you can see some future products that aren’t WE.

Liu and Liu. The factory is the child of Mr Liu on the left. The baby-faced Liu on the right was my tour guide and the  engineer/audiophile  (‘feverish  friend’  in  Chinese) behind DIYHFS kits and Opera products. The machine between them strings the filament on it’s frame.

Internal parts worked on inside this ‘clean box’ to reduce possibility of contamination.

Preparation electrolytic bath to provide the correct chemistry for individual parts.

After  parts are fitted, the bottom  is heated  and shaped  for insertion  of inner  glass component that the leads feed from.

After  parts are fitted, the bottom  is heated  and shaped  for insertion  of inner  glass component that the leads feed from.

followed by a trip  this  little Frankenstein device  which completes the evacuation.

This is the plate current during the final evacuation process. No one here worries about plate-glow, only non-glow.

Between each stage of production tubes are processed in these vacuum  and heating ovens  to eliminate
trace  gases and keep the temperature in  working range.

to the ultrasonic baths, but none were here at the time.

Then the ‘aging’ room. More plate glow. Somewhere in between the bases were attached; never saw that part.

This is Mr Liu at the control console (he built from scratch) developing a new tube (PX25). Each electrical parameter in individually controlled. Well we’ve been pressing for a 45. I saw the way he does it: RCA data sheet and official plate curves on the desk before him, Tektronix 570 curve tracer (thanks Ed Sawyer) showing the actual plate curve he’s getting. Not quite the same yet so another prototype is made with mechanical adjustments to the internal parts and try again. Many development cycles/prototypes before the original spec is achieved. Mr Liu said that the 45 has been a tough one. Also in the works is this PX25 mesh plate (almost done), and an 845.

This is Mr Liu and me. I was sure I had more hair than him. Must be the lighting.
And that’s the end. Time to get back to BJ, HK and SARS

Brian
2003