| Author: | DutchMarco (registered user: 464 posts ) |
| Date: | Sun, Jul 15th, 2012 @ 18:01 ( . ) |
Reason I'm suddenly interested in this, is that my project has very little space to put the xformers. To recap: 20w SE inc. big PT (Hammond 370fx), plus blues pre. It will become a tightly packaged 1x12 combo (will post pics later, for a better idea of what I'm working on. The chassis will be a vertical sheet if aluminium, with a horizontal sheet for the controls. In fact, very much like my 5F1 Vamp ( [link] Except now I'm planning to use a Heyboer OT, mounted off the vertical chassis, so in effect it'll be flatmounted. close to the speaker. And I'm going to stand the PT on the floor for best structural rigidity. Now, question: what would be the best placement for both xformers? Both close to eachother? Or separated as much as possible? (Meaning one will be by the input section, and one by the output. Sure the OT will be on the other side of the aluminium chassis, so should hopefully not interfere too much on the input tubes, but it's only aluminium, which doesn 't shield very well. I could put the PT near the input side, which would introduce lots of buzz Yes, I'm planning on doing the headphone trick as well, perhaps I ought to include the speaker, which will.be right in there, as well. |
| Author: | DutchMarco (registered user: 464 posts ) |
| Date: | Sun, Jul 15th, 2012 @ 18:04 ( . ) |
Darn, I messed up with the link: this is what that chunk of text shoulda looked like: [link] ). |
| Author: | DutchMarco (registered user: 464 posts ) |
| Date: | Mon, Jul 16th, 2012 @ 03:25 ( . ) |
OK, here are some photos I took: [link] and: [link] Showing hypothetical placements of the OT. |
| Author: | mhelyar86 (registered user: 1025 posts ) |
| Date: | Mon, Jul 16th, 2012 @ 04:50 ( . ) |
I may be wrong, but I think you need to ground the casing of the power transformer somehow if you're not going to attach it to the grounded chassis. This could be as simple as a chunky earth bonding wire (such as that normally used for grounding plumbing at least here in UK) securely joining one of the mounting screws to a dedicated bonding point on the chassis. There are other issues I'm thinking of though, such as the length of wires coming out of the PT on both primary and secondary and how you plan to do that without causing a lot of hum and while maintaining a standard of safety. I think your PT really needs to be on or nearer to your chassis, even if its actually bolted to the side of the cabinet, e.g. tucked up behind the chassis. |
| Author: | DutchMarco (registered user: 464 posts ) |
| Date: | Mon, Jul 16th, 2012 @ 14:11 ( . ) |
Thanks, but I had thought of that,, indeed I was going to use a long "ground-lead" BTW I'm going to hang the fuses off the wall of the cab, shield the leads with the shrinking stuff, wotsitcalled again? I'm guessing (/hoping) that twisting the leads will reduce hum to a minimum. BTW I've given it some thought and I think I'll place the 2 xformers by the PA-side, Angle them correctly (so the cores are at right angles to eachother, like so: -- | ) And I'll run the wires along the cab wall as well (clamped to it), which should be a fairly high standard of safety |