June 4, 201511 yr Looking good your so close now, betcha can't wait! You might get away by cutting the long al shaft into two pieces using a shaft coupler?
June 4, 201511 yr oh I was referring to mounting the alpha pot itself, I have the shaft coupler and etc. There's just no room where I can reliably mount the pot. I can probably use a zip tie and one of the adhesive ziptie mounts but that seems like such a hackjob. If anyone has any pointers to non-motorized quad rk27's I'm all ears
June 4, 201511 yr oh I was referring to mounting the alpha pot itself, I have the shaft coupler and etc. There's just no room where I can reliably mount the pot. I can probably use a zip tie and one of the adhesive ziptie mounts but that seems like such a hackjob. If anyone has any pointers to non-motorized quad rk27's I'm all ears one of my solutions : using the alpsquad PCB (http://gilmore.chem.northwestern.edu/boards/alpsquad2.zip) and fixing it in the back of the face.
June 4, 201511 yr I thought about that too, but I'll have to wait for a smaller pot to come in, like the balanced TKDs. I placed an order but I think there's a 6 week lead time or something
June 4, 201511 yr Author found this one yesterday, the 4 cathode caps for the outputs... same deal with the power supply, they could possibly short to ground, so either lift the caps a bit, or remove, put some kapton on the board and put the caps back. although no one has had this problem yet. updated board file has this fixed.
June 4, 201511 yr I think most caps should be ok due to the rubber pad they sit on. The snap in caps don't have this but still be careful. I think you might run into some problems with seven transformers inside the amp section. Ideally you should have two of them, each with two 6.3V windings just for the CCS tubes. The rest should be in the PSU box. Also EI cores are the worst when it comes to magnetic fields which is why I'm looking into R or O cores for this.
June 4, 201511 yr I haven't had any problems with my cathode caps in the few hundred hours I put on my megatron prior to casing. I think most caps should be ok due to the rubber pad they sit on. The snap in caps don't have this but still be careful. I think you might run into some problems with seven transformers inside the amp section. Ideally you should have two of them, each with two 6.3V windings just for the CCS tubes. The rest should be in the PSU box. Also EI cores are the worst when it comes to magnetic fields which is why I'm looking into R or O cores for this. hm really, that blows. I think at this point I just have to finish the build as is and evaluate how good/bad the performance is. What you're describing sounds like I need to hack up the PSU supply case and also use 2 umbilicals, 1 8-pin for AC and another 5-pin for DC, or something do that effect. Using toridals everywhere would also require a case change to mount things properly. What problems do you forsee? I read a bit into how to orient the transformers properly but it pretty much went out the window due to the size constraints. Did anyone opt for HV wire ( > 600V rating) for the bias umbilical? I haven't had a problem historically but I've never made an external supply for this. navships has some 2kv-rated wire appropriate for this but I don't know it's totally necessary.
June 4, 201511 yr Author birgir bought 100 feet of fancy high voltage wire. he wanted to buy 300 feet, but that was way over the maximum size and weight limit for shipping.
June 4, 201511 yr any particular stuff you can recommend? also related, does wire current carrying capacity specify ac, dc, or both?
June 4, 201511 yr Wire is almost always rated for AC. My plan for this was always to use two umbilicals, one which carries DC and the heaters (which are mostly DC anyway) and then a regular powercable to feed the amp box transformers.
June 4, 201511 yr Just use normal teflon wire for the bias with some heatshrink along the length. It will still be flexible enough.
June 15, 201511 yr I like it, not completely sold on that knob though is the board mounted to the carbon fiber? how easy was it to work with the material? last but not least, does it make your amplifier accelerate more quickly
June 15, 201511 yr i got the wrong measure about the face`s thickness..... yes,it is the 3mm carbon fiber. just using eight screws. what you mean the accelerate...(sorry for my poor English.)
June 15, 201511 yr i got the wrong measure about the face`s thickness..... yes,it is the 3mm carbon fiber. just using eight screws. what you mean the accelerate...(sorry for my poor English.) Carbon fiber on cars usual creates 50 extra horse power.
June 15, 201511 yr in other words, just a bad joke In other Megatron news, has anyone given thought to replacing the 1.5k resistors with 10m90s parts? I was thinking it'd resemble a beta follower, and the parts cost is pretty insignificant compared to the rest of the build.
June 15, 201511 yr While on the subject, the new Megatron board just arrived: Look Ma!!! Boutique caps!! Well that and a 12V filament for the front end, it's smaller and the ground plane is on both sides.
June 16, 201511 yr smaller board is always nice. this wiring is a straight nightmare, I have a mains short somewhere inside the amp are you going to stuff this with supremes?
June 16, 201511 yr i decide to built another "Platinum" megatron with full V-CAP CFTF and QUAD RK50. Totally take me about $2500..... and anyone has some ideas about the Resistors ?
June 16, 201511 yr smaller board is always nice. this wiring is a straight nightmare, I have a mains short somewhere inside the amp are you going to stuff this with supremes? Mine will feature a double mains wiring with a separate voltage selector in the amp chassis. Only way to do it properly. Yup, Supremes.
June 22, 201511 yr need to figure out some last bits and pieces with case feet and the potentiometer, but everything's working otherwise. it's been a while since I heard this amplifier, a lot of things to like.
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