Inexpensive kit for a beginner?

[The Reverend]

Hello, I am really itching to build something these days. I have the tools necessary and I understand some circuit theory (op amps, diodes, AC power, phasors, all first semester circuit analysis material) but in a somewhat abstract way. All of the construction I have done has been with breadboards and a large supply of all components (so frying an opamp or a diode was no big thing). I have a little bit of soldering experience, mainly from repairing broken guitar equipment and I one time, somehow someway, repaired a portable CD player. Anyway I just want some ideas for some kits that I can easily buy all the parts at one place, ideally as a kit with all the necessary components/enclosures/etc. that is useful, inexpensive, and fun to work with.

Thanks for any suggestions, I will look forward to replies!

[avionic]

So Reverend
What Kind of a kit did you have in mind ?

Dave

[fotno]

C'mon Rev, it's gotta be tubes man, tubes! Pre-amp kit mebbe?

[ashok]

Hi Reverend:

I saw your preamp thread over on the tube-audio part of AK. If you want to build a tube amplifier, take a look at the Spud - 2 to 3W based on the 6CL6 pentode, operating in triode mode. Cost of the complete kit is $285 including ground shipping.

Here is a link: http://www.hawthorneaudio.com/forum/viewtopic.php?t=523

I have not built the kit, although I did order the top plate and schematic from Jerry.

Ashok

[grumpy]

Theres always Dynakit :)

[mhardy6647]

The new Dynakits are very nice... not sure how much real "assembly" there is to do, though. I suspect the PCB's are pre-populated, as they were on the original Dynaco kits.

It is really hard to recommend a kit without knowing what you want to build, Rev! :-(

Velleman has a zillion things, available from www.partsexpress.com and elsewhere (e.g., Jameco). Maybe something from them'll float your boat?

http://www.ramseyelectronics.com Has a bunch of... interesting... kits.

If you want to build a hi-fi kit, Velleman has a few things, but something like the www.bottlehead.com offerings might be more fun and interesting. I am also sort-of enamored of the cheap and cheerful little amp-on-a-board from S5 Electronics:
http://www.s5electronics.com/tube12.html (also available from www.tubesandmore.com)
There're also Ron Welborne's kits: www.welbornelabs.com
Iconoclastic designer Bruce Rosenblit has some very cool things at:
www.transcendentsound.com

For solid state: are AKSA kits still available? http://www.aksaonline.com/products_main.html

any of these on-track?

[Walshdriver]

Slim pickens for kits now a days. When I was a kid there was Knight, Eico, Dynaco(sp) and a few others I have forgotten. There was always a build it yourself kit in the QST, amature publication.:tears:

[MikeO]

If you are looking at tubes you might try here. A friend of mine has built a couple of their tube pre-amps and was impressed. The company is Mapletree Audio Design. Website is

http://hollowstate.netfirms.com/

Mike O

[jcmjrt]

If you want to keep and use what you build then I'd recommend:

dynakitparts.com or
bottlehead.com

I have done business with welbornelabs.com twice and been gravely disappointed in their service for both kits and parts. The amps are good but the service was LOUSY.

[avionic]

that is useful, inexpensive, and fun to work with.
What is inexpensive?Solidstate is not expensive--Valves are a different story.


Dave

[mhardy6647]

Solid state is not expensive--Valves are a different story.

And what IS expensive, Grasshopper?

$24.80 (IC power amp)

http://www.partsexpress.com/imageslarge/320-212L.jpg

$44.95 (shortwave radio)

http://www.ramseyelectronics.com/images/largepics/SR2C.gif

$150 (phono preamp)

http://www.hagtech.com/images/bugle.jpg

$156 (as you see it)

http://www.s5electronics.com/images/dsc00012(13).jpg

$200 (sans enclosure)

http://www.sparetimegizmos.com/Hardware/images/6T9_Table_Small.gif

$369 (single-ended headphone amp/integrated stereo amp)

http://www.bottlehead.com/et/adobespc/S.E.X./SEXbacksideweb.jpg

$450 (Dynakit ST-35 power amp)

http://www.dynakitparts.com/store/images/productimages/zoom/51C.gif

$1239 (15 wpc stereo OTL)

http://www.transcendentsound.com/TranscendentT16Front01web.jpg


Other viable targets include the new Juicy Music Tercel phono preamp kit and a wide range of kits from Jim Hagerman www.hagtech.com

No dearth of nice electronic kits even now...

[The Reverend]

Wow, thanks for all of the great suggestions. I am really waiting on the schematic from PakProtector and just want something to keep me busy for a while. I was thinking about building a headphone amp, like a CMoy just to start off with inexpensively. I would like to build a tube headphone amp or phono stage at some point.

As far as price range goes, I am a college student so I definitely have to keep costs down. I am a physics major and will likely end up as an engineer at some point, so convincing my parents that learning a good skill like circuit construction and design principles is not out of the question. In other words, I could ask my parents for money, but I hate to do it, even though they are very generous. Anyway I would like to build something like the Foreplay or Bottlehead phono amp but I just can't get the cash for it right now.

I don't really care if it is solid state or tubes at this point, I just want to have a little bit of fun and learn some nitty gritty details about design/construction before I dive into a project like PakProtectors preamp. Thanks for suggestions!

Colin

[mhardy6647]

You can build a very cute (and very decent sounding) little tube headphone amp for about $150, thanks to Pete Millet. Add a source selector switch on the input, and it is a more than serviceable preamp. I used one as a preamp with my Bottlehead Paramours for about a year.

The original version is rat cheer:
http://www.pmillett.com/hybrid_head.htm
http://www.pmillett.com/file_downloads/ax_hybrid.pdf

http://www.pmillett.com/images/hybrid_head.JPG

Best of all, it uses low-voltage, space charge tubes and runs off a 30V wall wart -- no pesky high voltage to kill you :-)

http://img.photobucket.com/albums/v223/mhardy6647/TX2andbottlehead.jpg
http://img.photobucket.com/albums/v223/mhardy6647/realhifiglows.jpg

[The Reverend]

Very nice, that is the kind of price I am talking about. I will bookmark that page! Thanks.

[Paul C]

One of the amps pictured above is the K-502, a stereo 8 w/ch tube amp.

http://www.tubesandmore.com/scripts/foxweb.dll/moreinfo@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?item=K-502

One of my friends' son (about 16) build one of these and did a great job. This was his first kit of any sort.

http://audiokarma.org/forums/attachment.php?attachmentid=16861&d=1148917893

http://audiokarma.org/forums/attachment.php?attachmentid=16862&d=1148917893

http://audiokarma.org/forums/attachment.php?attachmentid=16863&d=1148917893

http://audiokarma.org/forums/attachment.php?attachmentid=16864&d=1148917893

Not bad for a first time!

Who has the link for the GainClone amps?

http://en.wikipedia.org/wiki/Gainclone

http://diyaudioprojects.com/Chip/LM3886_CA/LM3886_CA.htm

Edit to add: Here's the GainClone url http://www.chipamp.com/

Also, lots of kits here, solid state, and a few tube kits:

http://store.qkits.com/category.cfm/AUDIO

http://www.audiosector.com/

http://www.tnt-audio.com/clinica/ssps1_e.html

http://www.marchandelec.com/pm21.html

[gadget73]

Wow, I have this MP3 player! (the silver and blue brick-like thing in the lower part of the pic)

http://www.sparetimegizmos.com/Hardware/images/6T9_Table_Small.gif

I'm actually considering a tube pre-amp kit myself, once I get a mate to my Magnavox power amp and can run it in stereo. I'll check into the suggestions made here. Gotta love finding info I wasn't specifically looking for :)

[The Reverend]

Regarding these low wattage tube amps:

I know people say that tube watts are "louder" which I know is not completely true (a watt is a watt) and I know it all has to do with the acceptable amount of distortion in the signal and etc. But how about my speakers? They are wanting between 20-100 watts, will I damage them by clipping an 8 watt power amp? I have them hooked up to a 105 wpc solid state amp right now. How much of a volume loss would I experience by using an 8 wpc tube amp? Also, I hear bass response is somewhat weak with tube amps, hence my desire to use just a tube preamp and a solid state power amp. Any response to this?

Thanks,

Colin

BTW, thanks for those links, I will keep them in my bookmarks.

[Paul C]

Guys who build the low wattage tube amps generally use them with very efficient horn type speakers. Those speakers will knock you down with 1-2 watts, or at least give you very nice "live" audio levels.

At Audio Round Table there is even a "High Efficiency" forum for such speaker builders.

BTW, it is not true that big speakers require a lot of power. In fact, just the opposite. It is the small speakers that are power hungry.

Here is a picture of Jaymanaa's rear loaded horns powered by just a few watts of tube power--Jay tells me 5 watts per channel. They are not quite finished, no grill, not yet stained, but you get the drift:

http://audiokarma.org/forums/attachment.php?attachmentid=46727&stc=1&d=1176499657

[mhardy6647]

The amp power question is hard to answer. The good news is that you're quite unlikely to damage speakers with a tube amp, compared to a solid state amp. Tube amps tend to compress long before hard clipping, and are (IMO) much less likely to generate the high-power, high frequency chaff that an SS amp driven to nonlinearity will -- that's the stuff that (literally) smokes tweeters.

I listen to vintage AR acoustic suspension speakers with a ca. 12 wpc push-pull EL84 tube amp (Magnavox console hi-fi amp) in the basement regularly. The AR's are EXTREMELY inefficient; no one would EVER recommend using such an amp with them... but for the kind of music I like (mostly acoustic: solo and small group) at the level I like and relatively close field, they are entirely satisfactory. YMMV.

The bass extension/quality thing is hard to say. The S5 amp isn't anything like world-class in terms of either parameter -- but it's not embarassing, either. There's a pretty good review of it available from audioXpress magazine.
http://www.audioxpress.com/reviews/media/1102hansen2145.pdf

Say... you should get a subscription to audioXpress!! www.audioXpress.com

[Paul C]

Here's the GainClone chip amp thread:

http://audiokarma.org/forums/showthread.php?t=107623


Edit to add: Here's the GainClone url http://www.chipamp.com/

[stuartk]

I also wanted to mention Greg Ball's Simple Killer Amp (SKA).

His amp modules are available from bare PC boards all the way up to assembled and tested ones. Ditto for the power supply modules.

The prices are quite good, and you can get a 150W/channel into 8 ohms or 300 W/channel in 8 ohms.

I've been awfully tempted to build one up myself. I've talked to a couple of people who have done it and they say they're just great.

[cfranz]

This is a very nice (astonishingly nice) push pull amp. Puts out 8 watts or so. Last price I say was $165. You get all the parts, tubes, transformers, etc. to build the puppy. You can put it together in an evening.

http://www.tubedepot.com/diy-k12m.html


I built one several years ago and it is still in rotation in my system. It's small, easy to build and sounds surprisingly good. Also, there’s a ton of people with well thought out mods for this puppy. I vaguely remember someone making theirs ultra-linear. Here is a short list of places to look for mods.

diyaudioprojects (http://diyaudioprojects.com/Tubes/K-12M/K-12M.htm)

VoltSecond (http://www.siteswithstyle.com/VoltSecond/K-12M_AMP/K-12M_Push_Pull.html)


Good luck. Happy soldering.

[cfranz]

Sorry, didn't read the whole thread. I see the K-12M mentioned a dozen times.

[stuartk]

Regarding these low wattage tube amps:

I know people say that tube watts are "louder" which I know is not completely true (a watt is a watt) and I know it all has to do with the acceptable amount of distortion in the signal and etc. But how about my speakers? They are wanting between 20-100 watts, will I damage them by clipping an 8 watt power amp? I have them hooked up to a 105 wpc solid state amp right now. How much of a volume loss would I experience by using an 8 wpc tube amp? Also, I hear bass response is somewhat weak with tube amps, hence my desire to use just a tube preamp and a solid state power amp. Any response to this?


One problem with tube amps is that, in order to get good bass, you need a big output transformer. Lots of iron to keep it from saturating.

However, a big beefy transformer is not so good at higher frequencies. Part of the design process is striking the proper balance between bass and treble capability.

Most of the teeny tube amps that are so trendy right now are actually rather colored. You then select a speaker system to go with it that complements the coloration of the amp, so that the two sets of coloration add up to a pleasing whole.

I'm not really a big fan of tube equipment. I think you can do better for less money with solid state. I have a modded Dyna PAS preamp and a hybrid amp that I sometimes use, but I prefer the neutrality of the SS gear I have.

One tube amp that is likely to be very good and is available as a rebuild kit is the Van Alstine Ultimate 70. http://www.avahifi.com/root/equipment/amplifier/ultimate70.htm

You'd need an ST-70, but those are available used and even new, although that starts to bump the cost up a lot. You can get replacements for pretty much every part of the amp, so it's maintainable for the future.

I trust Frank's ears and he says it's really good, plus I know a couple of other people whose opinion I respect that have said it's a great amp.

I think this is a more reasonable amp than the teeny ones, and doesn't require you to limit your choice of speakers nearly as much.

I have found that the best tube and the best solid state equipment is getting ever closer to the same thing. Tight bass that's not boomy or flabby, a liquid, smooth sound without being syrupy, and precise highs that make cymbals sound like cymbals, without smear, and without being strident or harsh.

[gadget73]

One problem with tube amps is that, in order to get good bass, you need a big output transformer. Lots of iron to keep it from saturating.

However, a big beefy transformer is not so good at higher frequencies. Part of the design process is striking the proper balance between bass and treble capability.

Most of the teeny tube amps that are so trendy right now are actually rather colored. You then select a speaker system to go with it that complements the coloration of the amp, so that the two sets of coloration add up to a pleasing whole.



Some of the console amps were actually bi-amped for this reason. My old Magnavox console amp has a p-p quad for low-mid range, and a single ended section with a much smaller transformer for the highs.

[fortney]

Re headphone amp DIY--

1) check out headwize and head-fi.

2) Building a CMoy is an excellent idea. Refer to Tangentsoft.com

3) Tubes? Millet, SOHA MHHA, et. al.

None of these are real expensive.
There is a lot to be said for headphone listening if you protect your hearing. If you don't, then that would be too bad...

F

[fortney]

SRI-correction:

Tangentsoft.net

If you build a CMoy I suggest increasing the electrolytics to 470 uF and the input capacitor in each channel to 0.22 uF. It makes a significant improvement in bass.

F

[DanH]

I am not that great of a solder slinger myself. I have successfully built and use the Bottlehead Foreplay pre-amp and their Seduction phono pre-amp. I recently completed an Amp6 from 41hz. I am very pleased with it. It is a 15 watt chip amp and sounds fairly similar to my Golden Tube SE-40 amp. They have a interesting looking new 50 watt Amp10 kit if you need more power.