Alashikata: The chassis is all steel except the front panel and the L bracket (picture) holding the transformers, which are both aluminum. All big fasteners (not displayed) holding the toroids, and the rods are stainless steel). I had the same problem of yours with another preamplifier whose cabinet was all aluminum (even the base), except the top and bottom covers which were steel. I changed both the covers with aluminum ones and the hum mitigated a lot. The problem was the high transformer (E I) leakage flux, despite the presence of an external short-circuit loop made out of .3mm copper foil. Once replaced the transformer with two toroid ones, the problem disappeared.
I also heard about people having the same but opposite problem: hum with aluminum, and silence with steel. No comment, just want to let you know.
I also heard about people having the same but opposite problem: hum with aluminum, and silence with steel. No comment, just want to let you know.
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It's depend on the PT. Toroidal transformer seems be easy getting hum with steel for preamp. I am not sure about the power amp. The link below that I was encountered hum until I found out the steel chassis causing it after I tested on wood then I bought the aluminum to make the chassis.
https://www.diyaudio.com/community/...octal-acf-2-buffer.330985/page-5#post-6799068
After it put it's on aluminum, it's no longer hum. Even without choke, it's pretty smooth. Why don't you put everything on a piece of wood to test out.
https://www.diyaudio.com/community/...octal-acf-2-buffer.330985/page-5#post-6799068
After it put it's on aluminum, it's no longer hum. Even without choke, it's pretty smooth. Why don't you put everything on a piece of wood to test out.
I thank you for your concern, but the projects are closed and working. The first one was closed in 2003 (WOTS LeGrand V0.9), and the last one in the picture (Aikido) was closed last year. No hum! Sincerely, I don't like to build anything with tubes exposed.
By the way, did you read the topic we were talking about with Kodabmx? Try to remove the whole circuitry (2R, 1C) supposed to increase the PSRR, and connect the lower right triode grid to the ground with a 470R resistor. For both of us, the idea was the same, and I confirm the sound improved, and no noise from the power rail.
By the way, did you read the topic we were talking about with Kodabmx? Try to remove the whole circuitry (2R, 1C) supposed to increase the PSRR, and connect the lower right triode grid to the ground with a 470R resistor. For both of us, the idea was the same, and I confirm the sound improved, and no noise from the power rail.
oh ok, i didn't pay attention to 2R and 1C. I will look into this when I am going to build 12AU7 and 12BH7 PSRR.
That's great. I kept everything default. The calculate price is low but then the final price is higher in my case so take out $8 discount still be around $10. The board is around 135x56 mm. It's not a big deal but whatever hidden cost where I don't like it.
You have to apply the coupon during checkout (if you send the gerber from easyEDA, you get the coupon).
I did as you mention but whatever it's, I never get anything under $5 lol. All options are default, Either Green or Blue color is the same cost too.
I did order another one last week for $7.xx with shipping $8.xx to a total $16.xx but this was what I got after submitted for review they asked for another $20. I forgot to apply $8 discount but it's fine. The annoy thing was $20 additional.
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Thanks for placing your order on JLCPCB.COM.
You need to pay additional 20.34 for your order. 1bb2fa18de4a4a9cbff3d22eec9358f6_1668640319000_Y3【3279092A_Y3】
Reason:
1.The size for your order is smaller than the actual size so you may need to pay for an extra cost for the difference.
2.pcb supplement carriage money
Please note that this batch order won’t be put into production if funds have not been received.
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I did order another one last week for $7.xx with shipping $8.xx to a total $16.xx but this was what I got after submitted for review they asked for another $20. I forgot to apply $8 discount but it's fine. The annoy thing was $20 additional.
------------------------
Thanks for placing your order on JLCPCB.COM.
You need to pay additional 20.34 for your order. 1bb2fa18de4a4a9cbff3d22eec9358f6_1668640319000_Y3【3279092A_Y3】
Reason:
1.The size for your order is smaller than the actual size so you may need to pay for an extra cost for the difference.
2.pcb supplement carriage money
Please note that this batch order won’t be put into production if funds have not been received.
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