Jim Posted December 30, 2015 Share Posted December 30, 2015 Jim, If Mike doesn't take them all, and you have a quad and pair, I would also be interested. I don't think the quad I bought are Sylvania. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 1, 2016 Author Share Posted January 1, 2016 Okay. I'll check over everything tomorrow, power it up for a smoke test, and see how it sounds for the second pass in stereo. I've got a chassis on the way. I just need two 269AX Hammond PS xformers, two diode bridges, two 680 ohm 15 watt resistors, and a X or Y 1uF cap. I may need to reorder some parts due to use in the breadboard circuit. Happy New Year, Mike 1 Quote Link to comment Share on other sites More sharing options...
Jim Posted January 1, 2016 Share Posted January 1, 2016 Looks good to me, not that I can read all that, but it looks like the amp. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 5, 2016 Author Share Posted January 5, 2016 No turning back now... Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted January 5, 2016 Share Posted January 5, 2016 Mike, did you get the tubes I sent? Were they ok? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 5, 2016 Author Share Posted January 5, 2016 Yes, I got them yesterday. I haven't tested them yet, but physically they are fine. Thanks! Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted January 5, 2016 Share Posted January 5, 2016 Mike, the 17 X 10 chassis should work out really well. That's the size I used and, as you saw, there's plenty of room to work in there! Maynard 1 Quote Link to comment Share on other sites More sharing options...
Jim Posted January 5, 2016 Share Posted January 5, 2016 More than plenty of room, you could add on multiple inputs, multiple everything to this amp for the size of the platform it uses. Not that you would. I alsao like how Maynard used the furniture slides on the bottom with 3 in the front and 2 in the back for the heat to escape the vents easier. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 5, 2016 Author Share Posted January 5, 2016 (edited) More than plenty of room, you could add on multiple inputs, multiple everything to this amp for the size of the platform it uses. Not that you would. I also like how Maynard used the furniture slides on the bottom with 3 in the front and 2 in the back for the heat to escape the vents easier. I think (guess) that one goal Maynard had in mind when building the amplifier was to put two mono amplifiers in one chassis with power supplies, and to use a large chassis to keep electromagnetic interference, crosstalk, heat, and other things like possible parasitic oscillations to a minimum. Or to say enough distance from the power supply to the amplifier parts of the circuit to be safe. Hence the large chassis... I know, the chassis is huge. But I'm sure I'm not the only person who decided on a certain size of chassis for one's amplifier project, (be it tube, SS, amp or pre-amp) only to find out in the end that they bought too small of a chassis. Then ya gotta jam all that crap in a teeny little place, and then that creates problems with noise, EMI, heat, etc... For now, I'm going to just go ahead and use the James output transformers and mount them to the chassis, until I'm more flush down the road to afford another pair. I can fabricate a couple aluminum square spacers to cover the drilled holes from the James OPT's, and mount the new pair atop the spacers. Done right, it should still look good. So I'm going to have to stick with 250 volt B+ voltage to use the James OPTs and keep them under 90 milliamps, until I can afford a pair 2.5K 15-20 watt OPTs with higher DC current ratings. I'm definitely going to put a wood skirt around the amplifier chassis. Polish the aluminum really good, and then watch it tarnish in a couple weeks. Edited January 5, 2016 by mike stehr Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 8, 2016 Author Share Posted January 8, 2016 (edited) I mentioned this to Maynard, but not here. That the circuit pulls too much current from my Heathkit PS when setup in stereo. (both sides) I have another tube supply I can use, but it is a beast...not to mention it will take two power supplies, a variac, and a multimeter all piled up in the living room to just listen to the circuit. If I was still single, I wouldn't care and just trash the living room...but, I have to show respect. So I went ahead and bought a pair of PS transformers. So I'm just a handful of parts from having everything I need. I have enough hardware and sockets, and I would like to still use the ceramic tag strips...I like those things. I may get cute and use binding posts from scavenged multimeters. I know I have fuse holders, and power cords. I also have some chrome handles that will work out about right on each side. (somewhere) For now, a pissed puppy... Edited January 8, 2016 by mike stehr Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 8, 2016 Author Share Posted January 8, 2016 I have another tube supply I can use, but it is a beast...not to mention it will take two power supplies, a variac, and a multimeter all piled up in the living room to just listen to the circuit. If I was still single, I wouldn't care and just trash the living room...but, I have to show respect. py... pissed puppy two.jpg I am single but it is my Kitchen table you are referring to. There is not a lot of cooking going on in there anyway. My girlfriend will visit but does not stay for too long. It could be that this is the reason which may not be a bad thing. There was a retired EE audio friend who lived up here that was renting a 2 bedroom house with a full basement at the time. The only room that wasn't buried in audio gear or test equipment was his bedroom, (that I know of)...and the bathroom. He could cook in the kitchen, but you weren't going to use the dining room table. In spite of the clutter however, the place was always amazingly clean. While waiting, I'm revisiting my maggotbox 6V6 puss-pull mono amplifiers, to see if they can sound a little better than they do. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 10, 2016 Author Share Posted January 10, 2016 Still awaiting for parts, I brought out the Maggotbox PP 6V6 amplifiers, swapped back in the original output transformers, and adjusted the feedback for the best square wave at 3K that I could swing. I was using a pair of output transformers from a Admiral 6BQ5 console amplifier originally, and the overall sound was pretty bad. A bit harsh, with some stridency. After a week of listening to most my tube amplifiers and then these, it was pretty obvious they didn't sound that good. They do sound a bit better, but I still have some things I want to try. I should have used a socket with a shield, and should change that for starters. But I'll return to them at another time, I need to scrounge up necessary parts needed for the 6AQ5 SEPP... Mike Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 22, 2016 Author Share Posted January 22, 2016 Didn't puss out here...I'm currently figuring out where to drill holes in this nice chassis. I decided to use the ceramic tag strips because I couldn't really afford the phenolic ones. Cheaper to pinch them from scrapped scopes. In a day or two the rest of the parts should be arriving. All I should need now is a power switch and binding posts. Mike 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 25, 2016 Author Share Posted January 25, 2016 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 29, 2016 Author Share Posted January 29, 2016 (edited) A little more than 30 holes to go... Edited January 29, 2016 by mike stehr Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 29, 2016 Author Share Posted January 29, 2016 Heh...Xmas tree bits...never heard that before. Yes, stepped drill bits do speed up the process, and is a bit cheaper than buying a bunch of various sized drill bits. How often does one need a 1-1/8" drill bit? I notice with stepped bits is they will burr the hell out of the bottom side being drilled...It seems the best bet is to turn the piece over and use the stepped bit from both sides, as well as de-burr with the bit. The diameter holes for the output xformers are 44 millimeter, or 1-3/4". I didn't have a stepped bit that large, so I had to buy a hole saw. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 3, 2016 Author Share Posted February 3, 2016 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 3, 2016 Author Share Posted February 3, 2016 Still more holes to drill... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 7, 2016 Author Share Posted February 7, 2016 Acres of acorn nuts... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 27, 2016 Author Share Posted February 27, 2016 I'm about 85% done with assembly prior to wiring. I'm building the amplifier for myself and enjoy the process. So I tend to be methodic and slow, like a cat covering poo... That seems to be the part #. It's a 17" wide, by 10" deep, and 2" tall. It's a decent gauge thickness, roughly 1/16" thickness I would guess. Figure another 7 bucks or so for shipping. It worked out well...my only complaints is brake marks, and it's a soft aluminum. So don't get too aggressive. I'll posts some images later tonight... Mike Quote Link to comment Share on other sites More sharing options...
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