diy hifi poweramp?

[Narcosynthesis]

hello, i am looking at getting a new hifi for my bedroom at home (mainly due to the one i have sounding crap) and was wandering how hard it would be to diy it, i know zvex mentioned his new iMP only having something like 9 components per side, so even something slightly more complex would be manageable for me (a fairly novice builder)

so i was wandering if anyone knew of any kits out there for building a hifi poweramp, as i am guessing stuff like the transformers may be annoying to get easily, and getting a kit with everythign i need would be sweet

for what i need, i would prefer a couple of sets of inputs (for a cd deck or the like, and the vamp2 i have)(i guess i could add a switch myself to choose between two sets if it didnt come like that)
i dont need anythign particularly high wattage, i found a set of old speakers i will probably use (wharfedale laser 30's  anyone know if they are actually any good?) which are rated to 50 watts, but i doubt i would need that much for use at home (though extra power couldnt hurt)
i dont really mind if its a valve setup or transistor, i guess valves would look cooler, but either would do the job for me

so are there any places that do kits along the lines of what i would need? i live in the uk if that makes any differences (and uk places or anything)

much thanks

David

[nelson]

do a google for gainclone, I believe some places sell kits and apparently it sounds great, I have been thinking about building one myself.

[Vsat]

The Class-A "DOZ" amp on Rod Elliott's website is fairly simple to build and excellent sounding. It was not available as a kit, although that may have changed since I last checked. It is Class-A,  doesn't put out a lot of power, but will put out a very nice ten watts.
Cheers, Mike

[Ardric]

I've been reading the Chip Amp forum at DIY Audio:  http://www.diyaudio.com/forums/forumdisplay.php?forumid=40
and have been considering purchasing a kit from these folks: http://www.chipamp.com/
But I'd probably just make a great big Ruby out of it.

[Mark Hammer]

One person's "amazing" can be another person's "piece of crap".

That being said, do you have any idea exactly how many decent inexpensive power amp chips there are out there intended for higher-end use?  Once upon a time it was just the Sanken/Sanyo chips, but the choices available now from National Semiconductor, SGS/Thomson, Panasonic, Rohm, and others are immense.

Note that many (though certainly not all) such chips are aimed at the car stereo market, which means that they assume: a) a 12v supply, and b) bridged mode to provide most wattage at 12v supply voltages.

[Narcosynthesis]

I've been reading the Chip Amp forum at DIY Audio:  http://www.diyaudio.com/forums/forumdisplay.php?forumid=40
and have been considering purchasing a kit from these folks: http://www.chipamp.com/
But I'd probably just make a great big Ruby out of it.

the kits there look excellent

the only problem is i would still need to get a couple of parts myself, the transformer and finding a suitable chassis, but it looks like a pretty decent kit

are there any other kits anyone knows of?

David

[Johan]

if you just google "LM1875" and "datasheet" you get an exelent little hifiamp with a minimum of parts. and if you google "TDA2050"  ( and eqvivalent ) and "datasheet"  you even get a suggested pcbpattern and partslayout that works for both those chips...
I've used the LM1875 many times and it is great. easy to work with, up to 30watts into 8ohm (!!!) and usualy quite cheap...

johan

[zachary vex]

in the final design, the number of components has increased considerably.  i'm estimating about 35-40 components per side now.  haven't counted lately.  8^)  it got more complex.

[optimus_prime_1985]

a great place for quality kits is bottlehead.com  I have built his foreplay pre and parabee 300b monoblocks. If you decide to "roll your own" and don't know the db efficiancy of those wharfedale speaks, I would do an ebay search for a dynaco st-70. 35 tube watts per channel using 2 el34 will drive most any speaker you give it. It will need a preamp as the st-70 is only a power amp. For a pre, go with the bottlehead foreplay. super easy to build and sounds great! good luck

[Narcosynthesis]

a great place for quality kits is bottlehead.com  I have built his foreplay pre and parabee 300b monoblocks. If you decide to "roll your own" and don't know the db efficiancy of those wharfedale speaks, I would do an ebay search for a dynaco st-70. 35 tube watts per channel using 2 el34 will drive most any speaker you give it. It will need a preamp as the st-70 is only a power amp. For a pre, go with the bottlehead foreplay. super easy to build and sounds great! good luck

i intend using it with a cd deck (and possibly a behringer vamp2) so would that count as the preamp section, or would i need a pre between the cd deck and power amp?

David

[optimus_prime_1985]

The cd deck and most components have a line out. Meaning you will hear something but you will not have a volume control. A preamp takes that line level and amplifies it enough for the power amp to make use of. The preamp will also have your volume control. In a pinch I have used the headphone out on a cd deck that has a small volume control on it and this works fairly well.

[Narcosynthesis]

The cd deck and most components have a line out. Meaning you will hear something but you will not have a volume control. A preamp takes that line level and amplifies it enough for the power amp to make use of. The preamp will also have your volume control. In a pinch I have used the headphone out on a cd deck that has a small volume control on it and this works fairly well.

damn, i was kinda missing that part...

so in a normal 'separates' hifi system with cd/radio/tape/etc... deck, poweramp and speakers, the poweramp already has a preamp built into it? i know some have some tone control and volume, i thought that was just in the design of the poweramp, rather than a preamp (and now i realise that is kinda silly, comparing to somethign like a guitar amp)

so, to add to the diy poweramp kits, does anyone know of any good preamp kits too?

David

[zachary vex]

who needs tone controls?  8^)

volume, yes.  tone, naww... leave it be!  the engineer/producer/artist/mastering person wanted it that way!

[sean k]

I was into something a while back using a 6T9 tube which has a highish mu triode and a power pentode in one bottle and the real beauty was that Antique audio supply had the OT's for about $5.00.I've got the schematic on my PC but a simple search under 6T9 should turn something up.
And believe me..theres nothing better than SE hifi amps.

[Narcosynthesis]

who needs tone controls?  8^)

volume, yes.  tone, naww... leave it be!  the engineer/producer/artist/mastering person wanted it that way!

thats all i want anyway, i have never used the eq on my walkman or felt the need to play with bass boosts or whatever on my hifi (though granted, the hifi sounds crap - hence me upgrading)

i will go have a look for the 6t9 stuff

David

[Pushtone]

Here's several kits from 5 to 35 watts from CanaKits. They even have tone control kits too. I got my sine wave generator from them. Cost seems low considering you would have to spend the time to source these parts (not to mention the schematic and layout).

The home page:
http://www.canakit.com/

The amps:
http://www.canakit.com/Default.asp?Contents=/Include/Template/MenuCat.asp&Main=http://www.canakit.com/Contents/Divisions/Div_4.asp

I was thinking of getting the 35 watt w/ PSU to make pesdo-clone of the Tech21 Power Engine. (OT: I wonder how it would work for guitar?)
http://www.tech21nyc.com/pe60.html