Tubelab SimpleSE

[chrish]

G'Day All,

Have just finished construction of a Tubelab SimpleSE amplifier. Web site for the amp is here http://www.tubelab.com/SimpleSE.htm

George at TubeLab supplies the printed circuit boards for the amp and the information required to build the amp.

I have never owned or built a tube amp before and was looking to build an amp for my Lynn Olson Ariel speakers. I was looking to get an experience of building a tube amp without having to commit too much money, but also satisfy the competing criteria of a reasonable result.

The cct board supplied by George at Tubelab is well made and easy to populate. You have the option of mounting the larger components on the top or the bottom of the board depending on the mounting option you choose. I chose to mount the components on the back of the board so I could mount the board on the underside of the top of the chassis with the tube sockets protruding.

Power transformer is a Hammond 374BX 375-0-375 volt (I live in Australia with 240 volts)
Choke is a Hammond 193H 5H 200 ma
Output transformers Edcore XSE 15-8-5K ($19 each)
80 uF 500 volt motor run capacitor
JJ GZ 34 rectifier
JJ ECC81 (12 AT7) driver
JJ E 34 L output tubes

I have an active crossover at 80Hz with the low frequencies going to a solid state chip amp driving the woofer units recommended by Lynn Olson to accompany the Ariels, so George at Tubelab suggested that the low price Edcore output transformers would be good for my purpose (as well as being good value).

The build was straight forward. I put all of the components in a standard 12*10*2 Hammond aluminum chassis.

After triple checking my work (those high voltages scare me) and measuring the output voltages of the power transformer, I hooked up the amp in the basic triode mode, put a dummy load across the speaker terminals and plugged in a signal generator. Scope showed a clean output, so I hooked it up to my speakers and it worked.

After a couple of days I painted the chassis and hooked up the amp with all of the options: 80uF motor run cap, standby switch, valve (tube) rectification/solid state switch, triode/ultralinier switch, cathode feedback switch. All of those options makes for a bit of confusion and mass of wires in the chassis, but after double checking it all looked good and works.

As for hum, there is a little, but I have to have my ear just about in the speaker cone to hear it, so not a problem there.

As I have never owned a tube amp before, I cannot make any meaningful comparisons, however, I can say that I am very happy with the result, and am happy to have the amp as my main power amp (compared to home brew chip amp and adcom 555 power amps) on these speakers.

[chrish]

Another shot

[chrish]

Under the chassis

[chrish]

And the back end

[jduffy]

Nice job and it looks like you had fun doing it.

So what are you building next?

[chrish]

Ha Ha Ha,

Does everyone catch the bug once they have had a successful project?

My kids think it is cool looking, so next project will be something for my son. He has a laptop with pretty crappy internal speakers, so was thinking of building a very cheap flea power amp with some matching cheap single driver speakers in small cabinets for desktop. Any suggestions?

Cheers!

Chris

[Sherman]

Originally posted by chrish
Ha Ha Ha,

Does everyone catch the bug once they have had a successful project?

...

Chris

Yeah, you are pretty much a lost cause now. Soon your house (or shed) will begin to fill with various valves, transformers, caps etc.. You will disappear for long periods of time and your family will see a faint glow coming from the workshop area with occasional sounds of sine waves, odd buzzes and even music. You will emerge on occasion to eat and more rarely to shower.

Welcome valve amp building!

[tinitus]

Nice pictures

"do you have any suggestion fore a cheap flea-amp" ...... well, you live in Australia, what other than "Spud-kit" fom Hawthorne

http://www.hawthorneaudio.com/catalo...13d6ac1bd5a4bb

Hell, I forgot that Hawthorne may be US/Canadian

[tubelab.com]

Does everyone catch the bug once they have had a successful project?

Many people do! This is why you will see myself and others almost pleading with the newcommers not to start with an elaborate project that requries a large quantity of cubic dollars and runs on killovolts. The probability of success is much lower, and the cost of failure (emotional and monetary) is much higher.

As you found out a simple project that works the first time is rewarding and has the side effect of stirring the desire to build another one, often bigger.

I read your email and just replied. Thanks for the tips, they will be added to the manual.

As I stated in a previous thread on this forum, I will put your pictures in a "users amps" page on my web site. Anybody else have pictures of their Tubelab amps? Send them to me in an email, and I will post them.

[jduffy]

Originally posted by chrish
Ha Ha Ha,

My kids think it is cool looking, so next project will be something for my son. He has a laptop with pretty crappy internal speakers, so was thinking of building a very cheap flea power amp with some matching cheap single driver speakers in small cabinets for desktop. Any suggestions?

Chris

The Darling seems interesting for small power.

I built some bookshelf speakers using the Fostex FE-103 driver and they turned out really well. No bass to speak of but perfect for listening late at night when other people in the house are sleeping.

Look forward to seeing your next project(s)!