How would you go about constructing a tube amp?

[ProAc_Fan]

Hey tube guys! I really would like to attempt to build my own tube amplifier. What is the best way to go about learning all the necessary skills to accomplish this task. Also ( this is a dumb question) but is 30 watts of tube amp the same as 30 watts of SS. The reason I ask is my speakers are very inefficient and 200 watts is really what they need. Is a 200 watt tube amp feasible or should I look for another set of very efficient speakers to go along with say a 20 or 30 watt tube amp. I'm not abandoning SS, I am just curious what all the fuss over tubes is?
When it comes to tubes please assume that I know NOTHING because I don't. I'm much too young to have been around in the vacuum tube era!! ;)


Mike

[WildWest]

Good for you Mike! I think you are onto something that will forever change how you listen to music. Sure happened to me anyway. Also if you are mechanically inclined and patient why you could very well build that amp of yours.

If you are green at soldering there are a number of sites on line that will teach the fundamentals. From there it is mere practice. Its not a hard thing to do actually if you have a decent hand.

I understoond it to be that every watt of tube power equals roughly 2.5 watts of solid state. Read that somewhere and one of the guys here smarter than me can verify it either way.

Ya know, if your current speakers are very inefficient (and big floorstanders) ya might be hard pressed to make em properly fly with lets say a 30 watt per channel push pull amp. There are a number of kits for amps on the market but as you want more tube watts, you better be ready to step up to the plate and pay for them.

I didn't know all so much about tubes either until I got a Dynaco dropped in my lap. From there the flood gate opened for fun, tweaks, and a whole new sound that I was blown away by. No doubt my 95db speakers helps a lot. Anyway do searches on line and over at AA. You would not believe the TONS of information available to your every question. I will dig through my tube favorites folder here for info you may like and will post it later.

I am excited for you Mike!! :yippy: Tubes is a fun journey, sonically and otherwise. Nice to see others being open minded and venturing forth...You won't be sorry!

[MikE]

Yes, congrats on considering building an amp! I've never even considered that, mostly because I'm such a clutz with an iron and that I would be starting from ground zero. This is not to say I'm not interested or that I've not begun the learning process, which actually began last Spring when I began researching the Moth amp. Knowing I'd be customizing it I needed to present a half-educated proposal for the changes to the amp in it's stock form.

Regarding your quest. Not to add any fuel to the fires which have just begun to die, I can not too quickly suggest you haul your a$$ over to AA and at the very least lurk on the various forums; Tube, SET, DIY Tube, and Tweaks. I would also suggest you exhaust their search engine BEFORE posting questions. That is a pet peeve with some Inmates; asking redundant questions. The archives are awesome, you may not even need to post a question. Also check out the Bottlehead Forum (linked from the AA home page). Good luck and feel free to contact me directly if you feel I may be of further assistance. mwalsdor@cscc.edu

http://www.audioasylum.com/scripts/t.pl?f=tubes&m=84132

MikE

[Thatch_Ear]

Mike,
Try and find a specialty audio dealer that sells out of his house that is within driving distance of you and take some CDs with you. I really hate to say this because I do encourage listening to all types of gear, but building an amp is difficult and expensive and in many cases will not sound good on speakers that perform great with SS. It is also true that many speakers that sound great with tubes do not sound very good with SS and there certainly is not a power issue in those cases. But some things that work great with tubes just don't with SS and the other way around. All part of why this is so interesting before you even throw musical tastes into it. If after you get a chance to hear some good tube gear hooked up to some speaks that perform well with tubes and want to pursue the DIY amp I can help you out with lots of things at low cost if you can't get them up there.
Thatch

[MikE]

The one of component performance in the context of system compatibility. I think THAT is one of those areas that simultaneously gives our pastime a bad rap and is the cause of much debate / arguments / rock throwing among the various - Objectvist / Subjectivist - camps. How can one component not sound as good or have similiar qualities with various partnering components and unique systems? Well, they don't, thats rule number one. Change one freak'in thing and the balance is shifted. Which is not the same thing as saying the argument / theory of one coloration "correcting" another coloration. Which is somewhat true (if you will) but I prefer to not have a system of multiple crutches, one supporting another's fault. I'd rather have neutral sounding gear that wasn't dependant on something else (so much). The posts asking for "warm sounding" cables or even colorizations in tubes make me chuckle.

And about musical tastes, would you say that differing products, whether tube or SS are best served by a particular music type? That often times (though on a vast scale of dependancy) musical taste directs product selection? Like even within a product type, that SET and Push-Pull devotees have (often times) dissimiliar tastes in music or what they choose to embellish in replay?

MikE

[davechen]

I built a tube pre-amp from kit, Bottlehead.com's Foreplay, and had a great time. The instructions were very good, and the people on Bottlehead's forum page were very helpful.

As far as a 30 watt amp kit goes, the only one I saw was at DIYHifisupply.com. Their Ella kit is a 40 watt PP amp using EL34's. Here's an URL:
http://www.diyhifisupply.com/diy_kits/the_ella.html

I highly recommend building your own tube amp. There's no greater satisfaction than firing up something you built yourself. My next project will be to build a pair of Bottlehead Parabee's, 8 watt SET amps.

[gonefishin]

Pro-ac...keep us updated on your progress...what you decide...what you buy or build...and so on.

Are you looking to build a DIY kit? Build off a schematic? or to design your own tube amp?


take care.....

[ProAc_Fan]

I think if I build one it'll have to be a DIY kit. I couldn't read a schematic if my life depended on it.


Mike

[Thatch_Ear]

Mike,
Beware the claims of 40 PP amps. A pair of EL34s could maybe give you 35 but it would not sound good. They can do 20 watts and have no audible distortion if the amp and speakers are right. Also you want a kit that does not come with tubes. The tubes cost and what you will most likely get are what ever is cheapest from a in production factory and they will most often not sound good. Even very expensive amps that are prebuilt will sometimes come with cheap tubes that are only fit for burn in. But that was still maybe $100 to the builder and so cost you $200. Like I posted before you really need to listen to a system built around a tube amp that the owner of is a tube roller. Rolling tubes is trying same types but different manufacturers or same type and make but different run or production date. I even often change out the driver tubes for watching a movie because I have some with more gain that don't sound as good with music but are fine for movies and give me a bit more volume. (the signal from the player is lower in 5.1 than in 2 ch)
A for instance is that I know a horn designer/builder that has one of the Foreplay preamp kits and I took over some interconnects for him to audition and my 300B amp to compare to his 2A3 amps. I also took along a pair of 12AU7s as a gift. The interconnects were great and I was about to leave after unhooking my amp and as he was hooking his gear back up I pulled his RCA cleartop 12AU7s and popped in the ones I had brought and his system completely changed. We got goose bumps, the hair stood up on the back of our necks and all of a sudden it was just the music and not the gear we were listening to. Epiphany is is a good way to describe what happened. Poof it went from objective to subjective. 2 tubes I had pulled from a junk electric organ years before changed it all. Now this guy is buying every brand of 12AU7 he can get his hands on and is now a roller. His system before was very good, now it is much better, and he claims that his young teen daughter and her friends will sit and listen for hours and before it was just minutes.
In a nutshell if you have tube friendly speakers, you can build a kit, burn it in but you have very little chance of getting the tube experience at its fullest. It will be different than the SS you are used to listening to but you do stand a chance of being let down.
For my amp I have only 2 sets of power tubes because they cost so much, but I have maybe 10 different sets of driver tubes and every pair sounds different. The ones I like best were made for the US military in 1942. War technology makes for good audio later.
Thatch

[Lefty]

Mike;

Not owning or planning to own a tube rig I can only give you a few ideas. There are a couple of audio DIY mags that run construction articals. You could start small with maybe a preamp project or a small 5 watt amp that later could be use as a headphone amp if you move on to higher powered amps.

As far as is a watt a watt in the tube Vs SS world. Yes they are the same, wattage is a physical measureable value of power consumption of a circuit. To run 20 watts of power to a 8 ohm speaker requires 12.65 VAC regradless of what kind of output device is controlling that power.

So one should start with knowing what the real power requirements are for ones speakers at the desired listening volume one likes. If you really normally run at 200 watts of power then 80 watts of vacuum tube power is bound to be disappointing.

As far as, are 200 watt tube amps feasible? Certainly they can be designed and built to this and even high power levels. I'm just not sure you would like the price Vs SS amps of the same power rating.

Lefty

[bully]

Pro-A, let me add another plug for the audionova site that Thatch posted at the DIY forum. There are hundreds of sites linked through audionova, I mean literally hundreds devoted to building tube gear!
Thatch, that dang site has sucked me in for HOURS ... I hadn't been a 'puter addict but jeez, there are so many neat sites, a lot of personal web pages of guy's gear and projects. Whew.
Also many links to kit sellers, links to suppliers, etc.
Now, a watts is about 2.83V, but the characteristics of tube output compared with SS output are different ;)
When pushed to their limits, tubes behave more mannerly, and 2-1/2:1 may be a decent rule-of-thumb.

pete