Anybody here into tube amps?

"DoN. Nichols" wrote:


It had to be powdered iron made for low frequency work. I've used a standard variac to match an amp to speakers, and some PA volume controls are tapped autotransformers.
If he wants to try winding a transformer, small APC UPS have a nice laminated core, and scrap units are around for free. I currently have about 25 with bad batteries.

The FCC would have to catch someone using that radio. Since it was mainly used to listen, it didn't matter. The only downside was that you could hear some adjacent channel crap as high pitch noise if the transmitter was close enough. That radio didn't use ceramic IF filters.
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On Sun, 19 Jan 2014 06:05:37 -0800 (PST), " snipped-for-privacy@krl.org"

Greetings Dan, If I decide to wind my own laminations I'll let you know. Thanks for the offer. My local scrap yard is good but I cannot recall seeing and xmfrs there. Eric
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This is why transformer cores aren't solid iron: http://en.wikipedia.org/wiki/Transformer#Laminated_steel_cores "Early transformer developers soon realized that cores constructed from solid iron resulted in prohibitive eddy current losses, and their designs mitigated this effect with cores consisting of bundles of insulated iron wires."
http://en.wikibooks.org/wiki/Electronics/Transformer_Design
jsw
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Aww okay thanks.
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On Sun, 19 Jan 2014 10:39:37 -0500, "Jim Wilkins"

There's that damned Crazy Eddy again...
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Not meatloaf again!!
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On Sun, 19 Jan 2014 13:29:10 -0500, "Jim Wilkins"

I must have gotten a mote in my eye. What did you say? I don't understand.
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On Sat, 18 Jan 2014 22:05:03 -0800, "PrecisionmachinisT"

Winding a transformer like you describe above sounds like fun. There must be somebody selling the right kind of steel sheet for folks who want to make their own transformers. Eric
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It's vastly easier to recycle an old transformer of adequate core cross-section for your planned output power. You get the right size of bobbin to wind your own wire on. jsw
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On Mon, 20 Jan 2014 08:51:34 -0800, snipped-for-privacy@whidbey.com wrote:

Gawd, reaching back to Coleman College in 1987, IIRC, the stuff is called lamination steel. Low hysteresis + high permeability. Googlit.
If you get tired of trying to find stuff, here's a 12x12W kit: http://www.diyaudio.com/forums/siliconray-online-electronics-store/202156-fu-50-12wx2-hifi-tube-amplifier-kit.html
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On Mon, 20 Jan 2014 11:11:57 -0800, Larry Jaques

High silicon steel.
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http://www.ebay.com/itm/FISHER-VINTAGE-TUBE-STEREO-CONSOLE-AMPLIFIER-481A-/301074397355?pt=Vintage_Electronics_R2&hash=item46196eb8ab
http://www.ebay.com/itm/Magnavox-Stereo-Tube-Type-Audio-Amplifier-Nice-/380822013397?pt=Vintage_Electronics_R2&hash=item58aac2c5d5
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Better speakers, properly placed.

http://lenardaudio.com/education/14_valve_amps_5.html
jsw
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On Friday, January 17, 2014 3:18:36 PM UTC-6, snipped-for-privacy@whidbey.com wrote:

TedWeber.com
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On Mon, 20 Jan 2014 11:51:08 -0800 (PST), "Thanks for all the free

look at http://diyaudioprojects.com/Tubes/5751-KT88-Tube-Amp-Kit /. lots of others out there too.
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On Mon, 20 Jan 2014 11:51:08 -0800 (PST), "Thanks for all the free

try ax84.com - I think it is still active.
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On Fri, 17 Jan 2014 13:18:36 -0800, the renowned snipped-for-privacy@whidbey.com wrote:

If you ever run across something from McIntosh, in almost any condition, that would be a good bet.
Best regards, Spehro Pefhany
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On Mon, 27 Jan 2014 08:32:25 -0500, Spehro Pefhany

So I could either re-build the old McIntosh or just use the transformers and any good tubes to build my own? Probably rebuilding would be best, and I bet there are schematics available online. Thanks, Eric
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Mostly it is the electrolytic caps that dry out. Some are power and some are Bias or bypass / blockers - filters of all types.
Foil and mica don't go bad unless really high voltage is generated.
Good idea. Most tubes last and last.
Martin
On 1/29/2014 6:37 PM, snipped-for-privacy@whidbey.com wrote:

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