Since I've already got an FPE top plate design, could you keep the LED portion separable from the driver and have the holes match to the plate? That way, a builder can either use my mechanical layout or put the boards in any configuration desired. Here's the top panel layout, with the driver stage hole and tube locations marked in red, and the LED board mounting holes marked in green. I used the latter to bottom-light the EL84 through the perf metal where the tubes are mounted. There's pix and mechanical details at www.syclotron.com/?page_id=3 . The FPD file is at www.syclotron.com/rldtopplate.fpd .
I guess the grid stoppers on the EL84's should be attached directly to the pins of the output tubes -- not on the PCB -- how about the pair of 270k's?
Would it not be OK to have also the EL84:s on the board? The board could have a circle of vent holes around the tubes to allow for some air flow. I would prefer this option as it would be the simplest to build.
Another option would be to mount the board vertically (with the tubes horisontal).
Another option would be to mount the board vertically (with the tubes horisontal).
I now have 3 versions of SY's design -- I don't know what the situation is with posting pix -- they seem to disappear. I had enough room to squeeze in the Maida regulator:
An externally hosted image should be here but it was not working when we last tested it.
This what it looks like in 3D -- without the diode array -- to fit Stu's FrontPanelExpress Layout:
An externally hosted image should be here but it was not working when we last tested it.
Including the screen reg on the input board precludes using two regulators, thereby requiring matched quads of tubes.
Well, the way the chassis plate is laid out, there's room for two separate reg boards. If you want to use pairs instead of quads, just don't populate the main board and make two separate reg boards. The layout is up on my website in the RLD article.
I think I'd put another mounting hole between R1, R10, R13, and R17 to add some support for the board when inserting tubes. Maybe SY can add the hole to the FPE panel as well.
Also, why not put the grid stoppers right on the grids? Maybe it isn't absolutely necessary, but there seems to be no reason not to.
Third, I know SY thinks boutique caps are a waste, but some of us don't. How about a little more space for fancy coupling caps. Put them in parallel with the little boxes (like on the Aikido boards) and people can use whatever they like.
There also seems to be plenty of room for another regulator to me.
Also, why not put the grid stoppers right on the grids? Maybe it isn't absolutely necessary, but there seems to be no reason not to.
Third, I know SY thinks boutique caps are a waste, but some of us don't. How about a little more space for fancy coupling caps. Put them in parallel with the little boxes (like on the Aikido boards) and people can use whatever they like.
There also seems to be plenty of room for another regulator to me.
Other possibility is to use the on-board regulator to provide the 400V for the driver stage. I don't think it's necessary but it sure can't hurt. The raw supply, using the Allied transformer that the holes are cut for, can easily give 450V with a slightly larger input cap, so there's lots of headroom for a reg to work.
CharleyW said:
There's plenty of room in SY's chassis to put a separate Maida regulator for each set of EL34's -- it will probably bring him to tears to cut more holes.
The caps I show came in from Mouser a couple of days ago 100n/630VDC -- they are Vishay /Roderstein MKP's -- 695 x 318 mills, WIMA FKP's are 1220 * 500 mills.
I would guess the thing to do is devise an output board with a Maida on it -- perhaps change the bridging resistors to a pair of 560K so one can go on the driver board, the other on the output board...
I have to flop the LM317 and TIP50 so that the latter can be mounted to the chassis for heat sinking.
Especially because I have three already-made top plates just waiting for PCBs.😀
I use a small separate heatsink for the TIP50 since I'm always nervous about 400V and my chassis being separated by a few mils of mica.
I think we can do this -- put the driver (plus Maida), LED array, 2 output stages (with individual Maida regulators) on one PCB and make it such that the PCB is "snappable" -- to satisfy SY I can keep the hole positions for the Frontpanel work he has already done for the driver board. If you don't need an output board, no big deal.
My board house got a little cranky about "snappable" but given the economic state of affairs I don't think it will be an issue.
I can move out the size of the coupling caps from driver to output, but need some guidance on the dimensions for other coupling caps. I use everything from WIMA's and Roedersteins to Orange Drops and ASC.
My board house got a little cranky about "snappable" but given the economic state of affairs I don't think it will be an issue.
I can move out the size of the coupling caps from driver to output, but need some guidance on the dimensions for other coupling caps. I use everything from WIMA's and Roedersteins to Orange Drops and ASC.
Hi jackinnj
Tubelab (George) has commented that he is working on a board for an amplifier with exactly the same topology and tubes. In my opinion it would be a pity if two members came up with a board for the same circuit...think scale economy in the production of PCB's, etc. So I was thinking that maybe you want to exchange some ideas with him on this issue. Each is allowed to do what he pleases, but I see that most of these projects are not meant for profits, so I don't see a problem in a 'monopoly' position of board suppliers. On the other hand I may have this all wrong...
If they come out I will buy some as well!
Erik
Tubelab (George) has commented that he is working on a board for an amplifier with exactly the same topology and tubes. In my opinion it would be a pity if two members came up with a board for the same circuit...think scale economy in the production of PCB's, etc. So I was thinking that maybe you want to exchange some ideas with him on this issue. Each is allowed to do what he pleases, but I see that most of these projects are not meant for profits, so I don't see a problem in a 'monopoly' position of board suppliers. On the other hand I may have this all wrong...
If they come out I will buy some as well!
Erik
I just had a look at the previus page of this thread and saw that George already ordered his PCB's for the PP design... I thought it was still in the design phase...