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| palchiu Joined: N/A |  Message [#60] posted on: 11-08-2006 05:14 AM CST (US).   |  |  Dear AMB, C33~C36 pitch=7.5mm? Dia.=18mm? Thanks! |
amb  Headphone Council Joined: Apr. 1, 2004 | Message [#61] posted on: 11-08-2006 05:32 AM CST (US). | |
They are 7.5mm pitch 16mm diameter. I think that's more than adequate for this amp, because the transformer is smaller, and you shouldn't use too much capacitance there. Runeight's schematic shows four 4700uF 35V caps, and I think even half that capacitance should be enough. |
| cetoole HeadWizer Joined: Sep. 14, 2005 | Message [#62] posted on: 11-08-2006 07:51 AM CST (US). | | AMB, the 1455Q series works for me. I definitly understand how difficult it can be to shave even 1mm off the dimensions of a PCB in some situations, and how it can look to be pretty simple to do to someone viewing a picture of the layout, without the actual layout files that denote dimensions carefully. I am definitly for widening the board a bit to use the board rails of the 1455Q series cases, as it greatly simplifies casework for those of us (read: me) who are retarted when it comes to casework. I am sure there are plenty of others here who feel the same way regarding the casework, but until a few months ago, when my dog died, I would have said she could probably do a cleaner job of it than I, but since that happened, I believe I have likely pulled ahead, but just barely. I am betting this is just an artifact of Eagle's image export function, but some of the traces seem to be shorting, especially around some of the small signal transistors. Q22 is a pretty good example of this. |
Steinchen HeadWizer Joined: Oct. 12, 2005 | Message [#63] posted on: 11-08-2006 08:37 AM CST (US). | | I advocate widening the board, too. Main reason is the easier casework. I think the routing would be more relaxed if most of the small signal transistors had an inline footprint instead of a triangled shape. I attached a premature and prelimenary BOM for all the intrinsic impatient DIYers. Please note that it contains errors: board layout, lead spacings, IDs, etc are not settled yet. You may use it as a basis for your personal BOM and to get the info that you'll need about $150 to build a CK-III. Attachment: C2264.xls |
Ferrari HeadWizer Joined: Apr. 29, 2006 | Message [#64] posted on: 11-08-2006 11:38 AM CST (US). | | However casework is not an issue for me (planning to use HiFi-2000 case with slightly different dimensions), I also advocate widening the board a bit in favor of the layout work. AMB, since the board is a bit wider, maybe there is room for C33~C36 with 18 mm diameter and 7.5 mm pitch to provide more flexibility for these positions? It will be great if it's possible! I have some Nichicon Muse FX 4700uF 35V at my place and they are 18 mm diameter and 7.5 mm pitch. As far as I know Nichicon Muse FX is relative small comparing to many types of capacitors on the market. Probably Panasonic FC/FM are even small (or smaller) but I am not sure. |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#65] posted on: 11-08-2006 10:40 PM CST (US). | | Hi Steinchen, here are some info for your BOM. Some of this is based on my latest PCB layout which I will post shortly. C3, C4, C12, C13: ls=5mm dia=10mm
[Edited by amb on 11-09-2006 at 03:29 AM.] |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#66] posted on: 11-09-2006 03:32 AM CST (US). | |
No worries, they are not actually shorting. I've examined everything under high zoom, ran DRC checks, and verified every net against the schematic. |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#67] posted on: 11-09-2006 03:45 AM CST (US). | | Here is layout v6.05. - The board width is now widened to 4.7250" (120mm) to fit a Hammond 1455Q. The length is unchanged at 4.200" (107mm).
Attachment: C2265.png,C2266.jpg |
| Steinchen HeadWizer Joined: Oct. 12, 2005 | Message [#68] posted on: 11-09-2006 05:57 AM CST (US). | | looks good  I attached the updated BOM, including PCB and shipping I'd say somewhere around $140 (ballpark figure). With a cheaper volume pot and without the optional parts you may cut the cost down below $120. Then again with a nice frontpanel from FPE and some boutique parts going over $200 should be easy too. Attachment: C2267.xls |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#69] posted on: 11-09-2006 08:21 AM CST (US). | | Steinchen, I added the voltage regulator heatsink info for your BOM in post #65 above. Also, use 10K ohms for R40. [Edited by amb on 11-09-2006 at 08:23 AM.] |
| Ferrari HeadWizer Joined: Apr. 29, 2006 | Message [#70] posted on: 11-09-2006 02:19 PM CST (US). | | Very attractive PCB layout  . Thanks for modifying C33-C36 ! |
| Clutz HeadWize Fanatic Joined: Jun. 1, 2002 | Message [#71] posted on: 11-09-2006 02:54 PM CST (US). | | Would using an +/-18VAC transformer output too much voltage for the regulators to drop? I've got a +/-18VAC wallwart sitting around, and I've been trying to think of something to do with it. |
Mister X HeadWize Fanatic Joined: Jul. 23, 2003 | Message [#72] posted on: 11-09-2006 03:02 PM CST (US). | |
Nice update gentlemen. |
runeight Headphone Council Joined: Mar. 8, 2002 | Message [#73] posted on: 11-09-2006 03:27 PM CST (US). | |
Yes, you can do that. If you set the amp to 30mA idle per channel, your regs will dissipate about 3/4W each. They will get pretty hot, but the heatsinks are big enough to handle this if there is decent ventilation. But remember, this amp requires a DUAL secondary transformer. If your trafo is 18-0-18, then it won't work for this PS. It has to be 18-0, 18-0. Also, here is a small mod to the 6.03 schematic. I have changed one of the resistors from 100k to 300k. This gives slightly better damping in the servo. Steinchen you will see where this change is in the schematic and you can change the BoM. Also, may I suggest that you include an alternate set of servo components in case anyone wants to use the 6.04 servo. New 6.03 schematic attached. 6.04 attached just to keep everything together although no changes have been made since the previous posting of it. And now is a good time to talk about the optional components colored orange on the schematics. The first set of these are the 10p caps. Benny included these in his amp and I think that they are a good idea to retain. But I listed them as optional because you might be able to get away with leaving them out. I recommend, however, that you use them. The 220p caps are there to stablize the CFPs IF they should be unstable. In this situation it is not likely that they will be unstable and dBel84 has not experienced this problem. I think you can leave them out of your builds and if the O/P shows high freq oscillation, then you can put them in. In the PS (diagram attached again) there are 2u2 caps at the output of the regs. These are probably unnecessary too, but if you think that your regs might not be responding perfectly at high freqs, you can add them. I just tried to anticipate some possibilities with the original board design so that if you needed these components you wouldn't have to hack them in. AMB has been kind enough to include them in his revs too. [Edited by runeight on 11-09-2006 at 03:40 PM.] Attachment: C2274.gif,C2275.gif,C2276.gif |
| runeight Headphone Council Joined: Mar. 8, 2002 | Message [#74] posted on: 11-09-2006 03:30 PM CST (US). | |
Thanks! There are still lots of headphone amps to design and build. |
| Steinchen HeadWizer Joined: Oct. 12, 2005 | Message [#75] posted on: 11-09-2006 05:00 PM CST (US). | |
And you changed the capacitors from 10uF non-polar electrolytic to 1uF film. Is this regarded as an option or the new default ?
I'd keep them in since the fixed voltage regulators got high impedance at higher frequencies. Anything between 1.0uF and 4.7uF, boxed film or tantalum, should be fine here.
no need to search the thread back and forth for the latest one. [Edited by Steinchen on 11-09-2006 at 05:02 PM.] |
| runeight Headphone Council Joined: Mar. 8, 2002 | Message [#76] posted on: 11-09-2006 05:53 PM CST (US). | | Yes, the 6.03.01 is the default configuration. This uses 2x10uNP, 300k, 10k. There is an alternative given in 6.04 that maintains the same time constants, but uses 2x1u, 3M, 100k. I believe that either of these alternatives will work equally as well. So you can choose according to your tastes and component availability. This is why I suggested showing both alternatives in the BoM. |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#77] posted on: 11-10-2006 06:58 AM CST (US). | | Yet another update to the PCB layout. This is v6.06. - Swapped some power and ground traces between the top and bottom layers. - Added an output ground pad - a ring terminal is no longer needed. - Widened some traces. - Other minor adjustments.
[Edited by amb on 11-10-2006 at 07:38 AM.] Attachment: C2280.png,C2278.jpg |
| awpagan HeadWizer Joined: Jan. 6, 2005 | Message [#78] posted on: 11-10-2006 07:15 AM CST (US). | | i don't know, go away for a couple of days for work, and it seems it got busy here. My two cents amb allan |
| amb Headphone Council Joined: Apr. 1, 2004 | Message [#79] posted on: 11-10-2006 07:20 AM CST (US). | |
It's almost that way now. Virtually all ground is on the top side. The power traces are on the bottom because otherwise the ground traces would get in the way. |
| awpagan HeadWizer Joined: Jan. 6, 2005 | Message [#80] posted on: 11-10-2006 07:41 AM CST (US). | |
I see.. two 4700uF might be overkill yes, but this is diy. |
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