Stereo Tube Amplifier Enclosure

I have noted that high impedance of the S5 LS Tube Amplifier causes noise at output. I can hear "humm" and a little bit of high frequency noise in the speaker when the volume is at the high range.

The "humm" can be caused by a ripple of the power source, or by a coupling of the high impedance circuit with an external AC voltage. The high frequency noise suggest that a shield is needed.

I tried build some shield for the tube amp circuit with metal (aluminum) sheets. I have noted that the noise reduces significantly, but metal sheets are not functional. The shield should be visually pleasing too.

At the S5 Electronics web site you can find a enclosure specially designed to S5 LS Tube Amp.

I ordered this enclosure. In a few minutes you can mount the Tube Amp inside the enclosure. Some pics below.

The noise (humm and high frequency noice) was almost eliminated with the shield implemented by the enclosure. Good results!

Tube Amp Warm Up

I took a thermocouple to measure the tubes head temperature. I got 102 celsius at the 6005 tube; and 52 celsius at the 5670. See in the pics below.

The source power resistor also gets hot (96 celsius).

Assembling the Stereo Tube Amplifier (continuation)

Figures below sumarize the assembly steps of my S5 TL Stereo Tube Tone Control Kit.

Installing low power resistor.

Ceramic capacitors and 9 pin tube socket.

 Polyester film capacitors.

 Eletrolytic capacitor, junpers and pots.

 Conecting the junpers to the 16LS tube amp. All stuff integrated... then... power on!

My first impressions: the TL Stereo Tube Tone Control can emphasize significantly the bass and treble. The sound became deeper. Very good!

Assembling the Stereo Tube Amplifier

The S5 16LS Tube Amp is a two channels class AB amplifier.
There are four 6005 tubes at each output stage. They operate at parallel push-pull (PPP) configuration. This topology provides 16 Wrms per channel.
To excitate the grids of the 6005 tubes there are two double triodes (5670 tubes).

Optionally a preamplifier with tone control can be connected to the amp. I decide to use to use the called TL Stereo Tube Tone Control (s5electronics.com) to get adjustable bass and treble. This tone control has two channels adjustable RC filters implementing low/high pass filters (bass/trable) and preamps (5670 double triode tube).

Both the "S5 16LS Tube Amp Kit" and the "S5 TL Stereo Tube Tone Control Kit" come with good assembly instructions and tips. They can be ready to operate in a few hours of assembly work.

Figures below sumarize the assembly steps of my 16LS Tube Amp Kit.

Just low power resistor installed.

 Power resistors, tube sockets and RCA connectors installed.

 Power resistor spaced up off the circuit board.

Capacitors, rectifier bridge (there is no tubes on power source), pot and fuse clips installed.

 Banana conectors and cables from transformers installed.

Ready to instal the tubes and power on.

 Power on! No smoke, no explosion!

Initially I had problems with frequency oscillations. Then I remade the grounding connections at the output transformer feet and the oscillations disappeared.

My first impressions: clear and original sound. Very good!

Stereo Tube Amplifier

I wanna try the sound from tubes!

I've read on the internet that the cleaner is not always the most pleasant. It was written that a plain and clean wall without imperfections, depending on the place (the room, the environment, ...), sometimes is not nicer than a wall with texture ("lots of imperfections").
Then, the audio from vacuum tubes, even with its harmonics ("theoretically imperfections"), is always more enjoyable. I will try it!

After searching the internet for stereo tube amplifiers, I realized that they are very expensive. Currently stereo tube amps are commonly high fidelity (Hi-Fi) equipment.

An alternative would be to buy a kit of parts to assemble an amplifier. So I decided to buy a kit.

I found good prices and specs on Dynaco ST models and S5 LS models:
triodestore.com
s5electronics.com

I decided to order the S5 16LS model. I bought this kit at tubedepot.com.