Very inexpensive power amp kit?

royewest · 5296

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Offline royewest

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on: May 01, 2013, 08:19:38 AM
My goddaughter has started listening to vinyl and I'm hoping to set up a system for her room. I've started lurking in used places, ebay, garage sales, Goodwill, etc., but am also wondering if there is a simple tube system I could build for her. I can build a Quickie for her for a preamp. Her Dad has a phono stage she can use. So I'm hoping to find a kit or plans for a power amp for say $100., but I'm a little flexible.

Thanks in advance on any leads.

« Last Edit: May 01, 2013, 10:29:28 AM by royewest »



Offline HF9

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Reply #1 on: May 01, 2013, 11:06:01 AM
Phew, that's a toughie. tube amps are usually on the pricey side because of the iron (you need the power transformer and two output transformers). The DIYTube Budgie SE comes to mind. If you punch and drill your own blank chassis, you could get the cost down to $220-240. It's not a kit per se, just a circuit board, manual and bill of materials. I'd imagine if you have a few parts laying around you could get under $200 fairly easily.   

My DIY Audio Electronics Blog: DIYAudioBlog.com


Offline Paul Birkeland

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Reply #2 on: May 01, 2013, 06:57:18 PM
For ~$30, the T-amp will get the job done for you, and you could build in into the same chassis as the Quickie.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Zimmer64

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Reply #3 on: May 01, 2013, 09:49:45 PM
T-amp integrated into the Quickie has been done before by Fleawatt : http://www.bottlehead.com/smf/index.php/topic,3623.msg32238.html#msg32238

I have also built 2 T amps from jerry's Electronics. The are a steal for that kind of money. Check out Fleawatt's blog beforehand. He upgraded the caps, which I have tried and it is really worth the extra bucks, and recently he also upgraded the inductors.

Another idea might be a gainclone, if you need a bit more umpf. Chipamp or audiosector. I have built both and the are good too. I use them with the Quickie as pre. All you would need to add is a toroid. My recent toroids I got from Poland http://www.toroidy.pl . Very good price for a shielded and epoxy filled toroid. I was a bit sceptic at first, but they are reliable.

Enjoy.

Michael

Nelson Pass F5 Turbo V2, Quickie (mod), S.E.X. 2.1, Tubes4hifi SP14, Dynaco VTA ST 70, Tubelab SSE, Vroemen Diva Superiore ER4, Jordan JX92S VTL, 47 labs 0647 CD, Aqvox DAC, Rowen Absolute pre / psu / power amps, BG Neo3 / Betsy / Eminence A15 open baffles


Offline matthewmckay

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Reply #4 on: May 02, 2013, 03:04:55 AM
for the gainclone... (besides a toroid), you will also need a chassis, rca sockets, binding posts, wire, iec inlet, fuse holder, etc.  (and as an option, a potentiometer)/
  -these things will all add to the cost.   my GC kit from audiosector ended up running around $225.



Offline Chris

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Reply #5 on: May 02, 2013, 07:55:15 AM
Yeah , I ditto about the tube amp idea being TOO cheap just leaves you with  a high voltage circuit on an open breadboard  type thing which IS dangerous and will still run you over 2 benjies and sound maybe suspect. Better to wait and see how it goes with her and then plunk down on a REAL tube kit like the SEX later.... (just dont tell her that its called SEX...haha )... For now, like PB said, an inexpensive t amp will give her more power, good sound and is very cheap for her to get her "feet wet" with.... And as/if she gains a desire for more refinement later, then a bigger investment will feel much more comfortable...



4krow

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Reply #6 on: May 02, 2013, 09:42:18 AM
I would have to agree with the T amp idea. Sure there is always better, but not much at that price. I use one for my garage system, and another for my test bench. I would be willing to guess that the Q is of a bigger influence to the sound than the T amp. You are probably going to be pleasantly surprised at the sound.



Offline royewest

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Reply #7 on: May 02, 2013, 12:38:37 PM
I really appreciate all the advice so far. Thanks!



Offline RayP

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Reply #8 on: May 04, 2013, 02:20:03 AM
I would second the inexpensive T-amp idea. My daughter lives in Sydney and when I visited her last year I built a pair of Frugel-horns for her and also bought her a T-amp to power them. She has been very pleased with the results and apparently gets lots of questions from visitors who are quite impressed with the sound and the looks of the speakers and amp.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-300

For a bit over $20, you can't go wrong.

As others have mentioned, you have to spend about $200 to build a tube amp. It can be done for less but it is not easy as we found a few years ago for our 'build a 6V6 amp for under $200' competition.

http://audioratbag.blogspot.com/2012/02/bottleneck-6v6-competition.html

ray

Ray Perry


Offline Jim R.

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Reply #9 on: May 04, 2013, 04:08:14 AM
Yes, another vote for a good t-amp, especially with the Quickie as front end.  I like the one  from Jerry'selectronics mentioned and linked earlier in this thread.  Once you make up your mind, you can drop me a note of all the ancilliary parts you maight need -- binding posts, rcas, caps, poer inlet, etc.  I have tons of this kind of sstuff lying around and you're welcome to whatever you need and I have.

In fact, I also have plans to build a budget amp with the Jerry's board and the quickie, and all in one chassis, but that's pretty far back in the queue.

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Wanderer

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Reply #10 on: May 05, 2013, 07:54:32 AM
I have a Quickie and one of the original Sonic Impact little T-Amps. Together it makes a very decent sounding combo driving some Linaeum tweetered Radio Shack Optimus LX-4.

The Parts Express unit is pretty much the same unit. There are mods around for T-Amps if you Google them.     

Kevin R-M


Offline Grainger49

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Reply #11 on: May 05, 2013, 08:15:10 AM
I hadn't thought of a T-Amp but I have heard them. Not bad, not as good as a GainClone.  But it fits the price bracket.



Offline rif

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Reply #12 on: May 05, 2013, 08:57:35 AM
I have the lepai amp mentioned above. Currently use it in my garage and couldn't be happier.  IIRC, there are a ton of threads on other forums for tweaking it.

-david


Offline royewest

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Reply #13 on: May 05, 2013, 03:54:55 PM
Thanks again for all the advice on this thread.

I built Jerry's stock T-amp this afternoon and connected it to some ancient and inefficient Fried bookshelf speakers, with my cell phone and an album I uploaded to Google Play as FLAC as a source -- simplest way just to see if it produced sound.

Ya know, this is just astonishingly good sound. Some cymbal shimmer missing -- BFD for 30 buck or whatever and not even lossless source (Google Play downsamples your FLACs when you stream them).

I'm working on a Betsy order and am awaiting a Quickie kit.

One thing I did notice. At first I used an APS 15V transformer as the power supply and the noise was pretty disappointing. On a hunch, I replaced that with 2 cheap 9V batteries in series and the noise disappeared. Now I'm researching battery-based power supplies...
 



4krow

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Reply #14 on: May 05, 2013, 05:08:32 PM
I'm a big battery powered fan...it's cooool man. pun intended. Batteries are almost the best any time you can use them. They are partly what makes the Quickie great, and I think you are on to something with your idea as well. Keep us posted. Now where did I put that extra battery pack?