#124 low plate classic power caps

[norburybrook]

Hello all,

Well the bug has hit again, and as I have a chassis I've been unable to sell I've decided to build a #124.

Now, none of the usual suppliers are making boards anymore it seems, so I'm going to make my own this time...a first....

Anyway, looking at the classic power board the original has two 300uf/350v then 4 20uf caps.

Last ones I've made due to the power board layout, I used the ceriatone values of 2x 220uf, then 2x 22uf then 2x 47uf. All F&T axial.

Now as I'm making my own boards the closest I could get to the original values would be

Two radial nichicon 330uf and then 4x F&T 22uf axials

Which would be the best way to go here?

Cheers

Marcus

[ToneMerc]

Why not just use two 220uF axial caps for the mains filtering. In theory, the delta is only about 40uF between 110 and 150. How much of a tangible difference between is there between 110 and 150, especially if the amp is not driven hard.

TM

[martin manning]

I agree 110 uF is enough for the reservoir. See here for board layout: https://tubeamparchive.com/viewtopic.ph ... highlight=

[jelle]

Hello all,


Now, none of the usual suppliers are making boards anymore it seems, so I'm going to make my own this time...a first....

See here if you want to save a lot of effort.

https://tubeamparchive.com/viewtopic.php?t=29622

Jelle

www.welagen.com

[norburybrook]

I agree 110 uF is enough for the reservoir. See here for board layout: https://tubeamparchive.com/viewtopic.ph ... highlight=

Thanks Martin, never seen that before perfect.

@Jelle already spoke to Mike about those boards but I'd have top make a main board anyway, and I don't want the precision power supply or FET boards so I decided to make my own. It's about time I did the whole thing, going to do a cabinet as well this time myself

Any hints on making eyelets boards would be welcome..... I'm going to use garolite G10 I think it's called, just need to work out the thickness of board and eyelets and get a Staking tool.

I'm getting transformers from InMadOut in Italy again as they'll wind me a PT with a secondary for the relays instead of an extra transformer. They're also absolutely fantastic transformers. The set they made me for the bluesmaster were superb.


Thanks again guys.

I'll start a new thread when I get going, I'm on tour at the moment until second week of December then I start an album in the studio with a new artist straight after so not sue when I'm going to get the time to start this!!!


Marcus

[norburybrook]

Marting looking at your board and the resistors, they're higher wattage than the dumble original ones.

I've not been able to source 5w or 3w versions anywhere of those values. Mouser had an 11 week order time!!! And tube town didn't have any.

I've ordered 2w and 3w versions, I've a feeling that's what I used on my last build , will that be OK? Not had any problems with the other amps .

Marcus

[martin manning]

2W is fine for the dropping resistors, and 0.5W will be fine for the balancing resistors. The 2k7 5W is a wire wound cement type which should be easy to find, but 3W will be fine.

I edited the PS board and drew up the other boards with dimensions to fit the CE chassis and posted an updated .pdf in the files section. The FET board is there too... Took a bit of massaging to work that out using eyelets in such a small size, but I like the result.

Eyelet boards are very easy to make. If you use 1/16" G-10, 1/8 x 0.090 eyelets are the correct size. A suitable swaging tool can be found at a craft store for little cost, or you can use a conical center punch.

[norburybrook]

Thanks Martin.

I'll head over and download those now.

They will be very useful I think to other members now that no one is commercially making board sets anymore.

The relay boards are going to be fiddly as I'm going to have to find some way of wiring from the pins to the eyelets. I think putting them in a socket will be the best bet and small wires underneath from socket pins to eyelets.

Marcus

[martin manning]

You could use sockets, or just solder wires to the relay pins. Shouldn't be too hard. I've just added a relay board layout to the .pdf.

[telentubes]

For most boards, I typically use 1/8" G-10 and 1/8 X .156 Keystone eyelets.

Mouser link for eyelets... http://www.mouser.com/ProductDetail/Key ... rKvw%3d%3d.

1/16 is plenty of thickness for relays but I like to use 1/8" for all others.

[rogb]

Marcus, you can get proper eyelets from Modulus unless you are doing a Mouser order:
http://modulusamplification.com/Keyston ... 14746.aspx

[martin manning]

For most boards, I typically use 1/8" G-10 ...1/16 is plenty of thickness for relays but I like to use 1/8" for all others.

I can't imagine a ~2"x2" board needs to be 1/8" thick!? The main board perhaps, but strength-wise 1/16 is adequate, and there is so much damping from all the flying leads that stiffness is ok too.

[telentubes]

1/16" is way plenty. Fender used fiber board for main boards! Now that's flimsy.

[norburybrook]

Thanks guys.

We're all metric over this size of the pond so all these imperial measurements are strangely familiar (my dad and brothers were/are engineers) yet totally confusing when it comes to ordering G10 and eyelets!!

Marcus

[norburybrook]

So if I use 2mm board will 1/8'' x 0.93 (2.56mm) eyelets be the correct size?


Marcus