A critique on my first build please

ARandall

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Hi

After my thread a while back now on a possible Tweed Deluxe build, I've now had enough rainy Melbourne weekends to get some progress. The kit (from ceriatone) was completely parts, so I got to put in all the caps/resistors into the board too.

I have got to the parts where all the wiring that doesn't involve the board in some way is done, and the board is complete and now ready to be integrated into the chassis. I'm hoping you can look over the work I've done and point out anything you feel might be an issue before the board is more permanently fixed into place than just with the 2 screws.




The second issue is the parts list/resistor supply.
In the below pic I have something click-in and black....which looks similar to the mounting of an power indicator LED into a pedal housing. There were 2 of these and I don't know what its for given the power 'jewel' is fully complete.

In the pic above there is also an extra 1.5K 1/2W resistor (the one with the papered ends) which is sitting right next to its position in the parts list. 2 slots above are also 2 other 1k5 1/2W resistors which I found places for in the schematic.......but not so our lonely extra.
I'm wondering if this isn't an oversupply/mistake. All the other components of like amount/rating were grouped together in the list.

The OT has wires for 4/8/16 ohm. Now the layout says the 4ohm isn't used. But the pics I found from the ceriatone site shows the 4-ohm wire soldered to the switch - and didn't the operation of that take some working out:shock: - my question is....do you just not use the 4-ohm setting, or does the fact that the OT has the 4ohm tap means actually that it now becomes an option??
 

bilbarstow

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ARandall,

4-ohm could come in handy at some point, depending on what speaker compliment you want to run. If there is a switch position for it and the OT has the taps, no harm in hooking it up.

Your extra resistor, idunno. Probably just an overship, but I't double-tripple check the schematic. You don't want to have left out something important. No clue what the rubber grommet is for.

The pics look mostly pretty clean. Your twisted wires are probably not as good as they could be. May just end up with a little extra noise, or may just be fine, depending. Your red-black heater pair is really one wire rapped around the other for the most part, and that doesn't do much for noise rejection. Not sure about the yellow-red pair (is that the ohm switch on the back of the chassis?), that may be OK the way it is.

Congrats on your first build. Keep us informed as you progress. Somebody here may have better eyes / more informed comments than mine.
 

Soul Tramp

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Leave an air gap between the cathode resistor and bypass cap. The resistor will get hot and melt the cap.

As a general rule it's best to leave an air gap around each resistor. Elevate the resistors a bit off the eyelet board. This helps them shed heat. When a resistor get hot is can create hiss on the signal path. Especially CC resistors.
 

sonar

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Looks pretty good.

My suggestion is to clean up your leads around the tube sockets. Limit length to what's necessary and try not to overlap wire. Run wires parallel to each other as much as possible.

Again, looking good.
 

JohnnyN

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Looks good. I'm no expert but I would take the advice already given - less than perfect filament wiring can cause hum, and I've seen the marks hot resistors left on a PCB.

Congratulations on your first build :)
 

ARandall

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Hey, thanks all for the comments.

I've looked at all your posts and tried to implement all your recommendations.

Soultramp - those 2 components you mentioned I took to be the black resistor next to the blue cap on the power tube end of the board.

I've retwisted the heater and transformer cables.....not sure I did any better job this time really. I still think I have to develop 'the knack' (suddenly have an urge to listen to My Sharona:hmm:)

All the resistors have been lifted off the board a bit. And I've tried to wire up the tubes a bit neater and cut all loose ends off.

 

Soul Tramp

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There are two other cathode capacitors in your amp. They are the big bright blue round things. Make sure the resistor next to them is not touching. Looks like they are in your pic.

Move the red heater wires on the two 9-pin sockets up next to the sockets and trim the excess wire. As well, move the other wires as far away from the red/black heater wires as possible.

Check out this thread where I posted a picture of my heater harness wiring. You'll see how the wires are twisted and how they are connected to the sockets.

http://www.mylespaul.com/forums/squawk-box/366699-heater-harness-wiring.html
 

ARandall

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Thanks again. I'll look to those tips and post some more pics once I get another go at it.....bedtime now.
 

V2

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Q: you have what appears to be 1.5k resistors on two neighbouring pins of your octal tube sockets - to which pins are they attached?
 

V2

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ok, I see what's going on. I thought it might be a misplaced screen resistor (for pin 4)...
 

guitar-rocker

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I see on the Ceriatone layout that it shows the Mains ground on the transformer mounting bolt, but that is a bad idea. The Mains ground should be on a lug of it's own with nothing else on it, and don't use the transformer mounting bolts for any grounds. Nik should really correct that on his layouts.
 

V2

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A couple of suggestions:

V1 (far right of last photo):
- shorten green wire connecting pins 3 and 8; lie it flat on the socket
- instead of looping the red heater wire around the outside of the socket to pin 9, run it right up the middle, over the green wire.
- shorten the black wire running from the board to pin 6 of V1. Make sure it is separated from the wires going from the board to V2 (or you'll run the risk of getting oscillations at higher volumes)
 

Soul Tramp

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A couple of suggestions:

V1 (far right of last photo):
- shorten green wire connecting pins 3 and 8; lie it flat on the socket

It may be my bad eyes, but it looks like that green wire is connected to pin 2, not pin 3.
 

Frogfur

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I've got a CeriaTone, 18 watt, with a few of my own modification ideas.I'll post some pictures tomorrow. Yours looks great.
 

V2

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It may be my bad eyes, but it looks like that green wire is connected to pin 2, not pin 3.
Yeah, it looks that way.

ARandall - this wire should be connecting the cathode pins (3 and 8)...
 

ARandall

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Ok, thanks for the tips - you guys have been great in helping me out!!

The green had been soldered to the wrong pin when I redid the heaters for the 1st time.

I've redone the heaters yet again - thanks for that thread Soultramp.

I've also made all of those mods you recommended V2.

Some pics:

 




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