Given you're in Canada, an alternative to Digikey for Hammond stuff (though the free shipping > $100 is nice) is a1parts.ca. They seem to have the best Hammond prices.
I don't know where on the prairies you are but if you have need of tube related iron, sometime, send me a pm, as I might have something and I'm starting to 'de-clutter'. I have a number of items I'll never use but which might be suitable for a guitar amp, like a Hammond 277x60 (1000 v ct @ 200 ma, plus a 600 v ct winding @ 75 ma, and 5v & 6.3v filament windings). I also have some chokes, filament transformers, and misc power trannies suitable for lower load items like line stages, etc. Then there are the 2000v ct plate transformers with associated chokes, all weighing a figurative ton, that are difficult to use, and harder to ship.
I don't know where on the prairies you are but if you have need of tube related iron, sometime, send me a pm, as I might have something and I'm starting to 'de-clutter'. I have a number of items I'll never use but which might be suitable for a guitar amp, like a Hammond 277x60 (1000 v ct @ 200 ma, plus a 600 v ct winding @ 75 ma, and 5v & 6.3v filament windings). I also have some chokes, filament transformers, and misc power trannies suitable for lower load items like line stages, etc. Then there are the 2000v ct plate transformers with associated chokes, all weighing a figurative ton, that are difficult to use, and harder to ship.
Nice work as always THD+N. I have always enjoyed your postings on Audio karma.
@prairieboy , I know what you mean about decluttering. I have many transformers too! A few years back, here in Winnipeg you could pick up consoles with PP 6v6 or SE el84 amps, for free to 50 dollars. I bought a nice stereo el34 PP electrohome Versailles in 2019 for 50 dollars I believe it was, what an exciting find that was! Seems something has changed and while the deals are there prices have gone way up! Maybe the hipster market? Its just as well because my wife was losing her patients with all my wonderful finds ! LOL. I have built many champs and Supro, fender clones with those small platforms and also built several rh84 amps designed by Aleksandar Kitic and the iron from SE console amps sound wonderful using that circuit. I mostly sold those to friends at break even. Anyway prairieboy shipping has become obscene in Canada, but I appreciate the offer. I only buy in Winnipeg now. I have two set of those UL electrohome outputs in my build above, one pair from a PA-600 and the other came with the powers, chokes and output transformers from an Electrohome Concord Imperial. I'll attach the schem if you are interested. I paid 900 bucks for that lot on Canuck audio, but I couldn't pass it up and shipping was quite reasonable because I took them all. Cheers!
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Just wanted to share something. I noticed buying consoles in years past. Sometimes the seller (who were often children selling there deceased parents stuff) would ask what is your plan with this console. In the beginning I would tell the truth and say I was planning on repurposing the amplifier for a smaller tube amp design and would scrap the rest. It was the truth, right? On two different occasions the sellers cancelled the sale. So I decided I would always tell the seller I was going to restore the unit. Obviously most of us cant buy console and store them in our basements because divorce proceedings would be on the horizon.
So I think that wee lie is Okay, no? I often cut up the console and use it to build small guitar combos and heads so it's put to a good use. The rest gets burnt in the woodstove!
So I think that wee lie is Okay, no? I often cut up the console and use it to build small guitar combos and heads so it's put to a good use. The rest gets burnt in the woodstove!
Like pianos - nobody wants them either. I took apart a 100 year old Heintzman this summer. That was a project! I'll repurpose the wood that's usable. Interestingly, most people think pianos are made of wonderful solid wood. Wrong. They're glued up panels of mixed hard woods - ash, elm, hickory, red oak, which are then cross-veneered with thick veneer (virtually unobtainable now) on both sides, then thick veneered parallel to the wood grain with the face veneer (quarter cut white oak, mahogany, etc). The exposed edges are veneered as well. These panels, a forerunner to plywood, are stable where panels of solid wood would move and distort.
Indeed, you see the same thick ply method in many old consoles too! however it appears that aspen is often the thicker core wood. Is the sound board done in this method too ?
The sound board was an edge-glued panel of thin (1/4" ?) strips - possibly white pine or Sitka spruce. I had hoped to use it, but it was glued to a number of strategically placed thin ribs. Having the strong back of 4" x 4" oak beams immediately behind it, with a 200 lb metal harp in front soon wrecked that idea. Heintzman made incredibly solid, yet intricate, pianos.
Hi THD+N, These are taking me a long time to finish! I'm working on them this weekend. Question about how to implement both elevated heaters and humdinger use in the original schematic. I have a center tap on the heater winding. I usually dont use a humdinger. I'm not 100 percent clear how to best connect these. Would both the tap and the wiper connect to the divider? Thanks in advance.
You shouldn't need a hum pot, really. I've never used one. To elevate the heaters, connect the center tap to the "top" of the output tubes' cathode resistor. That will raise them about 40 volts.
There are various ways to "terminate" the heater circuit with a center tap...
- Simply ground the center tap.
- Place the center tap at the node of the cathode/resistor.
- Use a humdinger pot.
I have even eliminated the cathode pot and I am only using a single 325r/25W wire-wound resistor. Performance and THD numbers are spot on.
I even swapped in & out 10 pairs of output tubes to see if there was much deviation with not having an adjustment in the output tube cathode circuit and test results between pairs was nominal.
I even swapped in & out 10 pairs of output tubes to see if there was much deviation with not having an adjustment in the output tube cathode circuit and test results between pairs was nominal.