eggil Posted March 3, 2015 Report Posted March 3, 2015 (edited) Working on the amplifier chassis. Used 6 mm aluminum for everything except for the front panel, which is 10 mm. The filament transformers will be hanging down like bats. That's what the outer holes are for. That way all the wires will be in the same plane. Edited March 3, 2015 by eggil
Earspeakers Posted March 3, 2015 Report Posted March 3, 2015 Working on the amplifier chassis. Used 6 mm aluminum for everything except for the front panel, which is 10 mm. The filament transformers will be hanging down like bats. That's what the outer holes are for. That way all the wires will be in the same plane. Looks beautiful, and looks like a design I'd like to do. Please post your FPE files for us.
eggil Posted March 3, 2015 Report Posted March 3, 2015 (edited) No problem. I'll do it tonight when I get back home. Nopants also wanted them. Edited March 3, 2015 by eggil
Kerry Posted March 4, 2015 Report Posted March 4, 2015 Nice Eggil. You could also consider putting in blind taps for the standoffs.
eggil Posted March 4, 2015 Report Posted March 4, 2015 (edited) Thanks Kerry. I'll post the FPE files as soon as I can. I am on a PC not my MAC currently. Just assembled part of the chassis to make sure everything fits, and it does. Never mind the front panels are upside down. Easy fix The LED's are on top. Made 4 holes for them. Edited March 4, 2015 by eggil 1
Earspeakers Posted March 4, 2015 Report Posted March 4, 2015 Looks great eggil. Also tell us where you got the chassis sides. Looks like a great solution, if you don't mind I'll probably do that. With thinner panels though, don't need ones that thick.
RiStaR Posted March 4, 2015 Report Posted March 4, 2015 Very very nice Enrique. Love the color theme!
eggil Posted March 5, 2015 Report Posted March 5, 2015 Thanks! I guess HC does not allow FPE file uploads
xianghao Posted March 6, 2015 Report Posted March 6, 2015 Thanks! I guess HC does not allow FPE file uploads http://www.mongofiles.com/ http://www.xun6.com/ maybe they can help you.
eggil Posted March 16, 2015 Report Posted March 16, 2015 (edited) After running the amp for about 30 minutes, a low hum develops in one channel. If I turn it off it goes away when I try I later on. I wonder if the temperature is too high inside the case. The top panel gets hot. The thing is, when I just turn it on even a few minutes later, it sounds great without any noise whatsoever. Edited March 16, 2015 by eggil
kevin gilmore Posted March 16, 2015 Author Report Posted March 16, 2015 bad input tube usually causes this.
JimL Posted March 18, 2015 Report Posted March 18, 2015 Easy way to check if it's a bad input tube is to swap input tubes between channels and see if the hum moves to the other channel with the swap.
RiStaR Posted March 19, 2015 Report Posted March 19, 2015 Not sure I understand your question, but those circled headers are the right ones if you don't use the RK27. If you used an RK27 and it's mounted then yes, because they are connected to those headers the mounted attenuator will affect it. Even with the RK27 fully open (max volume) you're still getting channel imbalance? [you should be able to measure the attenuator with a DMM to see if it's bad - at max volume setting especially] I assume you also tried to swap the tubes around to make sure it isn't the tubes?
xianghao Posted March 19, 2015 Report Posted March 19, 2015 Not sure I understand your question, but those circled headers are the right ones if you don't use the RK27. If you used an RK27 and it's mounted then yes, because they are connected to those headers the mounted attenuator will affect it. Even with the RK27 fully open (max volume) you're still getting channel imbalance? [you should be able to measure the attenuator with a DMM to see if it's bad - at max volume setting especially] I assume you also tried to swap the tubes around to make sure it isn't the tubes? Even with the max volume,imbalance still happen. About the tube, i try my best to swap them,i don`t think they are bad. Based on what you say,measure will be done tomorrow(maybe). Anyway,thanks RiStaR.
RiStaR Posted March 20, 2015 Report Posted March 20, 2015 Even with the max volume,imbalance still happen. About the tube, i try my best to swap them,i don`t think they are bad. Based on what you say,measure will be done tomorrow(maybe). Anyway,thanks RiStaR. Not sure I'm helping... just suggesting some stuff Just to be clear, I meant to swap left channel tubes to right channel tubes as a check instead of swapping all of them.
spritzer Posted March 20, 2015 Report Posted March 20, 2015 Just for the record, there have never been any 2SA1968's with exposed tabs. Every last one ever made (i.e. real ones) had fully enclosed packages. The 2SA1967 on the other hand has an exposed tab but they are pretty rare.
eggil Posted March 24, 2015 Report Posted March 24, 2015 (edited) Well, I checked everything and could not find anything wrong. No more hums though. Not sure what it was. The 009's sing nicely with it. Have listened to them for hours at a time without trouble. And the temperature on the top panel is between 53 C on top of the transformers, 63-66 C between the big tubes, 51 C on the front and 57 C on the back of the top panel after a couple of hours. Edited March 24, 2015 by eggil
mypasswordis Posted March 29, 2015 Report Posted March 29, 2015 Can anyone confirm that the BATE amp board terminal block gnds are not actually connected to the gnd plane? I modified the traces in the input stage to put in the Megatron CCS and noticed after poking around with a DMM that they don't seem to be connected.
spritzer Posted March 29, 2015 Report Posted March 29, 2015 They aren't connected. This is from a great software update which caused some major fuckage on a number of boards.
nopants Posted April 11, 2015 Report Posted April 11, 2015 Was shopping for some filament transformers for my cased build of the Megatron, the ones in the center are driving 2 x EL34 so I think those secondaries need to be at least 3A.
spritzer Posted April 11, 2015 Report Posted April 11, 2015 The current draw of the EL34 is 1.6A but it's +/-10% so a minimum of 4A is what I'd use.
eggil Posted April 12, 2015 Report Posted April 12, 2015 I swapped to 12AU7 from left to right sides. The intermittent hum still happens only on the right channel and it's intermittent of temperature or use time. Sometimes it happens within 5 minutes and sometimes it takes 2 hours but invariable disappears when I shut down the amplifier, but it comes back again without regard of time or temperature. Otherwise it sounds great in between humming episodes. Any ideas?
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