Simple Tube amp

[sifis_samos]

Guys please enlight me a bit..i just finished building a Gainclone Amp from Audiosector, and i am very satisfied..now i want to try something diferent..
I was always intrigued by tube amps but never dared to build something.
So i will say clearly what i and i thing many users may want.

I am thinking of a design/project of a Tube pre/final amp using tubes. my source will be my iPhone or a cd player.I need it to be around 25-30Wrms at 8Ohms.More watts are welcome of course , or less if it is worth..

I am thinking of a all hand wired simple construction.
Please if you have something in mind let me know. I know nothing about tubes so a practical step by step construction is welcome. Please dont recomend me exotic (aka too expensive) stuff!.. The only thing that i ve seen and i liked it very much is the shape of a KT88! SWEET...All the transformers needed will be ordered uppon starting of construction..

So what i need is: as simple construction as possible, with the less measurments-adjustments possible, and around 25-30Wrms at 8ohms..
Thanks in advance!

[Glowbug]

Odd Blocks - KT88 Push-Pull Class A DIY Tube Amp with 12SL7 Driver

Close to 25W with KT88s...

TriodeElectronics Dynaco Mk3 Tube Amp Kit

Uses PCBs, but more power.

[Richard Ellis]

Try tubelab.com!!.............Hes' a cool dude from Florida.......been an engineer for ...long time.
Hes got this little business on the side & he writes in this forum all the time.all around great guy.
His designs vary from the basic to wild.

__________________________________________________ ______________Rick....

[tomchr]

First off - why 25-30 W? Are you planning to level the neighborhood with it? Are you throwing techno rave parties on a regular basis?

The "how much power" question comes up a lot, so I decided I'd find out how much power was really needed for my needs. For my listening, I tend to turn up the volume to drown out background noise and to be able to experience the dynamic range of the music. I have measured the output voltage of my amplifier with an oscilloscope while listening to the music. I have reached the conclusion that for "critical listening volumes" (high enough to drown out other noise, loud enough that I would have to turn it down to carry on a conversation with someone), the output power is on the order of 0.25 ~ 0.50 W RMS. Yes! One quarter of a watt! Once I reach about 1.0 W RMS, I start turning the volume down. Otherwise, I know my ears will be ringing for the foreseeable future. This is with 87 dB efficient speakers in a small-ish (25 m^2) living room that's fairly live (longer reverberation time). Allowing for some crest factor (the ratio of the peak power to the RMS power), I'd probably design for 5-ish watt minimum. But of course, your needs may be different. Currently I'm running with a tube amp that maxes out at less than 2 W and I don't really find I need much more power than that. A little more would be nice. Which brings me back to the 5 W... Unless I need to rock the house of course... But for HiFi listening my <2 W is fine.

I recently dove into tube amp design myself. I'm an electrical engineer and design semiconductor circuits for a living so I have a solid basis in electronics but had never tried tube circuits. I was looking at making my first project a large push-pull amp that could deliver the 30-ish W you're looking for. But after looking at it, I decided to start small. Simple and high power just don't go together. So I'm designing a Spud from scratch. I'm getting closer to being done with the design and will post it here once I'm done. As you can see from the Spud thread I've hit a couple of snags along the way. I'm having fun, though.

If you are getting into tube design for the design experience, I would follow the path I took. But if you just want to assemble a circuit and get something working without killing yourself, I strongly suggest looking at some of George's (tubelab) designs. For example the SimpleSE. You don't have to use a PCB, though, unless you have stellar soldering skills, I would highly recommend it. Remember that you're dealing with potentially lethal voltages!

Good luck!

~Tom

[JPeitzman]

I would re-evaluate if you really need that much power to drive your speakers. I would for sure check out Tubelab gear, it was listed above along with a link. Check out the El Cheapo too. Depending upon how the outputs are wired it will do somewhere between 5 watts and 15 to 20 watts. The El Cheapo is just that, a cheap but high performance design that would be easy for a beginner to throw together. Poinz at AudioTropic has a similar design with either 6V6's or EL34's.
http://homepage.mac.com/planet10/for...3jun06-map.gif
Audiophiletalk - Bargain Basement

THE MUSICAL MACHINE; IMPLEMENTATION.
http://www.diyaudio.com/forums/attac...rectified-.gif
Just some thoughts

Cheers
James

edit: BTW, the 6V6 Musical Machine has been updated with a similar front end as the EL34 Machine.

[sifis_samos]

Originally Posted by tomchr

First off - why 25-30 W? Are you planning to level the neighborhood with it? Are you throwing techno rave parties on a regular basis?

The "how much power" question comes up a lot,


~Tom

well to be honest the reason i ask for a 25-30wrms amp is that i base my opinion on my ic amps performance with my current speakers. my speakers have 85db sensitivity, and with the gainclone yes they play wonderfull! BUT using a small Tamp using the Tripath 2020 they just dont play good enough..
i listen a lot of rock, and acoustic music with many vocals and i tend to squize a bit my volume knob in oder to "listen" while working..the Tamp seems shallow and incapable to drive these speakers. I dont intend right now to build other more efficient speakers..

The problem is i know nothing about tubes and i dont have huge equipment. i have a Multimeter and a LCR meter. I may have access to an oscilloscope but to be honest i dont know how to use it!!
Thats why i ask for a simple design with point to point instructions. with as less measurments *** possible..if you thing that a 5w project is better to start with then i may try it!...but it must have preamp on it.not just the final stage.a line in is what i need.

[sifis_samos]

the THE MUSICAL MACHINE; IMPLEMENTATION seems attractive with great explanation on the each part used..

[trondareo]

I&#180;m in the same situation, basically; I am listening to Magnepans, which the myths say need hundreds of watts to sound good, Actually thay are rated at 90db/m and way over powered with a 30W SET amp. At ear damaging volumes I use about 1/2 of the volume dial. (which is logarithmic).

Just for fun I tried powering them with a 1watt 13EM7 SET amp I am building from Fred Nachbaurs design. They didnt manage to drive the Maggies and distorted badly but I bet a 10 watt amp would do quite well.

The problem with my amp. The Audioromy 838A FU13(813) is the lethal voltage innvolved, about 900Vdc. So I&#180;m also in the marked for an easy to build, amp in the 10-18W area.

I have been playing with he idea of a 6c33c based SET for instance this thing: 6C33C Single-Ended 1

[netbug]

I followed the same path you are on.. started with a few Chipamp builds than started into tubes. I highly recommend starting with a circuit board based project. Or build a few point to point chip amps to get the hang of p2p without the risk of instant death.

You should consider the soon to be released Tubelab SimplePushPull. It will provide more power than the SimpleSE but still allows for a safe/clean build.

[Nikolas Ojala]

I vote for high efficiency (full range) speakers and low efficiency Class A amplifiers. This way, for example: High Efficiency Speakers