Jazbo8 is correct. The sort of power mentioned is hideously expensive, when obtained from tubed amplification. $500 will not be enough for "iron".
If tubes are truly in the OP's future, the 1st order of business is to acquire reasonably sensitive speakers. Something 94 dB. sensitive will do nicely with as little as 8 WPC.
If tubes are truly in the OP's future, the 1st order of business is to acquire reasonably sensitive speakers. Something 94 dB. sensitive will do nicely with as little as 8 WPC.
How much knowledge of tube circuitry do you have?
If you are willing to complicate the output stage you can dramatically reduce the cost of the OPT's.
For 25-30W you'll need an actual tube amp power transformer, but if you can deal with about 15W you can use toroid power transformers as OPTs and an off the shelf power transformer and save a couple hundred dollars. You will get a 15W (18.5W on the datasheet) push pull class A tetrode connected amp using 6P3S Soviet tubes using a standard Williamson front end. It won't be a "kit" per se. You would have to wire it all point to point.
Here's a schematic of one I'm building today... 6SN7 can be replaced with 6N8S, too.
I didn't include the heater supply but I personally use a 12V 10A SMPS for LED strips for the heaters. Tube pairs connected in series parallel.
Cheers.
If you are willing to complicate the output stage you can dramatically reduce the cost of the OPT's.
For 25-30W you'll need an actual tube amp power transformer, but if you can deal with about 15W you can use toroid power transformers as OPTs and an off the shelf power transformer and save a couple hundred dollars. You will get a 15W (18.5W on the datasheet) push pull class A tetrode connected amp using 6P3S Soviet tubes using a standard Williamson front end. It won't be a "kit" per se. You would have to wire it all point to point.
Here's a schematic of one I'm building today... 6SN7 can be replaced with 6N8S, too.
I didn't include the heater supply but I personally use a 12V 10A SMPS for LED strips for the heaters. Tube pairs connected in series parallel.
Cheers.
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Hi, I don't know what people here think of this site..... DIY AUDIO PROJECTS - Do-It-Yourself Hi-Fi for Audiophiles
Posters here are right. 25W+ is going to be hard to find for $500 in a kit. Even sourcing parts yourself without having to worry about the mark-up for a kit, it's a tight budget. Your transformers alone will run around $200 at least, add $100 for a quad set of output tubes, and you'll have $200 left over for all the passive components and chassis. Not impossible, but it would be tight and would limit some of the possibility for bells and whistles (tube rectifiers, mono blocks, AB2 operation, etc).
If you stretch a bit you can get a VTA70 :
VTA ST70 $859 + shipping IN KIT FORM
with all parts and tubes and EL34 output tubes
all parts included, and the result is state of the art
tubes4hifi amplifier KITs page
Do you really need that much power?
I run an 8 watt per channel tube amp and it does quite well for me.
Admittedly I did add powered subwoofers later to fill in the low end but
that's mostly because my Mains are small full-range drivers on my desk.
Had I gone with larger and more sensitive speakers I could have
probably gotten away with just the mains and no subwoofers.
That being said the 8 watts per channel I run is more than enough.
16 watt Per channel Amp $290 and the Case $92
Optional Tone Control $73 or Phono Preamp $51
I have no idea on the quality but from what I have read they
seem OK and I've been tempted to buy one from them.
.
I run an 8 watt per channel tube amp and it does quite well for me.
Admittedly I did add powered subwoofers later to fill in the low end but
that's mostly because my Mains are small full-range drivers on my desk.
Had I gone with larger and more sensitive speakers I could have
probably gotten away with just the mains and no subwoofers.
That being said the 8 watts per channel I run is more than enough.
16 watt Per channel Amp $290 and the Case $92
Optional Tone Control $73 or Phono Preamp $51
I have no idea on the quality but from what I have read they
seem OK and I've been tempted to buy one from them.
.
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If you buy all the parts from Digikey (including a Hammond chassis, excluding Soviet tubes from eBay, about $50 for 4x 6P3S and 4x 6N8S) the cost is about $500 CAD.
If you source the resistors and caps from China you can build it for about $400 CAD. You might also buy a 7 dollar 12V - 45-390V boost module for the front end as 300V is a tad low, as the first tube would have only 45V on the plate at 3ma when run from 300V. I added one yesterday and it made the phasing and balance better.
DC-DC 8-32V to +-45V-390V ZVS Step-up Boost High Voltage Capacitor Charge Board | eBay
I've included a pic of the finished amp.
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The chassis, unless you are really good at metalwork, is always my biggest issue with DIY builds. If you outsource it, the price can get expensive, almost hitting the cost of the iron.
I have, of course, made some gear on bud boxes using nothing but a drill with a stepped bit and a range of bits.
I would second the Dynakit ST-35 amplifier, which can be built stock and then upgraded as time permits.
Barring that, a simple DIY single-ended or push-pull amplifier. Like TubeLabs' SSE (or is SE?), or, Eli Duttman's El-Cheapo. The former has a PCB board available, while the latter can be done point-to-point.
I did build a $600 10WPC single-ended amplifier from scratch, using 1625 output tubes. But I already had some of the parts on hand!
I have, of course, made some gear on bud boxes using nothing but a drill with a stepped bit and a range of bits.
I would second the Dynakit ST-35 amplifier, which can be built stock and then upgraded as time permits.
Barring that, a simple DIY single-ended or push-pull amplifier. Like TubeLabs' SSE (or is SE?), or, Eli Duttman's El-Cheapo. The former has a PCB board available, while the latter can be done point-to-point.
I did build a $600 10WPC single-ended amplifier from scratch, using 1625 output tubes. But I already had some of the parts on hand!
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