• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

My First Tube Amplifier

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Well, guys I wanna start off by saying hi!:)

I have been hanging around the decware site for some time now dealing mainly with Steve Deckerts car audio subwoofer designs. But lately I have been getting a strange itch to build and hear one of these "Tube amplifiers" everyone over there raves about.

SO, I started looking for a good introductory project. But alas, I cannot find everything I need to start building all for the same amp. If its not having trouble finding the ancient tubes the design calls ofr, its trying to find modern day transformers or places to buy them.

Basically, I hunted for about two weeks and found out only a bunch of stuff on how the tube works what kinda of designs, etc. And, well, this site. I figured after searching here and seeing all the amazing pics you guys have and the beautiful amps that you all would be able to help me out.

So here's the dilema: I wish to build a small tube amplifier that will amplify RCA, line-in, and stereo plug outputs, although line-in would probably be the only one I need. It will be used with a set of Steve Deckert's Personal Planars(Quiet an awesome design check herefor more info: http://www.decware.com/newsite/mainmenu.htm under speakers on the left, Personal Planars). They will be hooked up to this tube amp and run for my computer speakers if everything works out. The speakers are 86db sensitivity, but the planar design supposedly raises that. They are 5 watt rms and work well with a very small SS amp I have.

Can anyone point me in the direction of a cheap, easy modern amp design with an actual parts list I can obtain?

Thank you all sooo much!:D
You can find most any transformer you might need at Angela Instruments (http://www.angela.com). Other places to look for various components include-

Triode Electronics
Antique Electronic Supply
Euphonia Audio

and tons more. Triode Electronics has an online schematic section with *lots* of schematics for various types of amps.

For inefficient speakers Sy's recommendation for a P-P amp is very good but a single-ended design will have a lower parts count and be (in general) easier to build. If you are listening in the nearfield to computer speakers a SE design of 2 to 6 watts would work fine I think.
I saw the "86dB" and didn't notice they were computer speakers. Mea culpa.

Make that "push-pull EL84 amp in the 10 watt class." One very nice circuit (though you'll have to source the parts yourself) is the Bevois Valley Amplifier shown in Morgan Jones's book.

These days, even Mouser carries output and power transformers.
I was looking for more of a site with an actual amp project that would be cheap to build and uses modern parts. I have no trouble finding where to buy the parts, I have been to several of those sites already, I just can't find a design with a clean and clear cut schematic and parts list.

Like a site that says: "This amp can be made for this much using these parts available at this place." and then shows me the amp's output and design schematic.

I guess I am just not finding enough info on what parts everything is, there is a lot of schematics, but they have just values. I would need something that says, for instance, buy 3 330 ohm 5 watt resistors. Or buy the hammond transformer 12bse. or whatever.

Or if someone has built an amp for dirt cheap, can they help me out? I really want to spend less than $100. but am willing to pay more if I need to. Surely this isn't to unreasonable? but if it is, please tell me so! All of the help so far has been great though, that angela electronics seems to have some very good prices.

I am not aware of any amplifier under $100. However, I remember that for 139 or so, you can get e kit and all parts (except the case) for a 8Watt amp.


Look for some threads in the forum about this amp. Some people here have done it. There is also some sites about modifications to improve the sound. It does not seem to be an impressive amp, but for that money... it is probably a good first project. I haven't built the amp or listen to it. May be some of the guys that tried it can help you more to see if it suits your needs.


Another approach is to get a vintage stereo amp and restore it. Many can be found on that auction website that shall not be named... :)

You'll need to replace all the capacitors and check the resistors. Generally, the tubes that came in it may or may not be good, but if
it sat usused a lot, the tubes are likely okay. Caps on the other hand do not age well. Used or not, 40 year old caps should get replaced. The transformers, if not abused, should be fine. Avoid rusty chassises, as some of that moisture probably also got in the transformers, making them prone to leakage failures.
Two suggestions:
1. Go to the Angela site and look at their How To page. Check out the Single Ended EL34 Amp, with a full parts list. It's not dirt cheap, but is not exotic either.

2. Check out boozhoundlabs.com/howto/ for a simple amp with that rarity, a discussion of the design process, along with a parts list and a lot of construction guidance.

And--safety first--please heed all warnings and enjoy.
"I built my amp from thiswebsite and I think you can built them easily below US$100. The EL84 pentode mode should give enough power and idea of how a tube amp sound for a start."

I am thinking of building one of these with the CCS and using Pl84's. How does yours sound. Have you anything to compare it to. This will be my second tube amp having already built a 807 based parafeed amp. I'am not expecting the diyparadise amp to compare, but hopefully it should come close.

I have built the 8W tube amp kit that Radames suggested (http://s5electronics.com/gpage1.html). Actually, I built two mono kits that I purchased from Antique Electronics Supply (http://tubesandmore.com). The specific kit is the KC501. You get all the part for a very nice 8W amplifier built around the 11MS8 tube designed by George Fathauer. After you build the amp kit(s), you can then easily surf around and find several nice websites about this amp design, including one site with very nice tweaks to install high speed diodes and fillament snubbers. The kits are ~$90 for the mono, ~$140 for the stereo (same price as s5). And if you want to hand wire on a chassis instead of use the included PCB, you can still use the kit(s), buy a chassis and chassis mount sockets, and have most everything else you need to complete the building. I find the 8W tube amps to be nicely musical, and they get plenty loud enough for listening through the nearfield monitors in my home recording studio.

By building a kit, you will learn along the way, yet not have too much to invent on your own. I found it to be an excellent starting place. Another good starting place is to find an old tube amp in a garage sale. Even if it's a PA amp that would make audiophiles cringe (like my McMartin MA-50), you will learn how to read schematics, adjust balance, replace caps, manage high voltage safely, and then have something worth giving to your kid for guitar.

Just my $0.0000002. I'm certainly still a tube noob, so this is just an opinion, not steeped in decades of experience.

> I am thinking of building one of these with the CCS and using Pl84's. How does yours >sound. Have you anything to compare it to. This will be my second tube amp having >already built a 807 based parafeed amp. I'am not expecting the diyparadise amp to >compare, but hopefully it should come close.

I have made comparison this amp to my el34 which I build some 10 years ago. Built them with the CCS, it will give a boost and add more dynamics to the sound.

On comparison to the EL34, the EL84 lacks a little bit on the lower, this could be due to the 20W against a 10W power. However, in terms of clarity, mid range and 3D, the EL84 is much better.

I am using a FS2000 ( fostex ) speaker when doing this comparison.

Anyway, the EL84 is with a friend who is having a hard time departing with it.

Hope this helps.
I discovered this wonderful website yesterday when my 7 year old Kenwood amp died. I have often dreamed of building my own speakers, but never in a million years did I imagine people were making their own tube amps! I feel like a kid in a candy store.

I have the same basic question as the bloke who started this post (looking for a cheap, easy-to-do, kit-type amp for toob-noobs), but would just like some further clarification:

I own JBL HLS820 speakers. Are any of these amps suitable for speakers of that size?

Thanks for the welcome, SY.

I copied and pasted this from the JBL website. I hope the information you're after is in it! :) If it's not, let me know and I'll look harder.

• Sensitivity (2.83V @ 1m): 90
• Impedance: 8
• Bass Driver: Dual 8"
• Midrange Driver: N/A
• High-Frequency Driver: 10mm mounted in Constant Directivity Horn
• Recommended Power Amplifier Range: 50 - 250 watts
• Dimensions (H x W x D): 39 3/4 x 9 3/4 x 11 7/16"
• Frequency Response (±3dB): 40 - 20kHz
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