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SOHA II Builders Thread - Page 29

post #421 of 1686
Thread Starter 
hayduke, bmwpower is right about running the power to the front. You can certainly try it, but I would test it before committing to a hole in the front panel.

Nice to hear about your build. Can't wait to see it.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #422 of 1686
hmmm I know I posted a reply last night. That's twice in 2 days my posts have disappeared. I guess I offended the forum fairies or something

I'm already planning to build it and get everything working before I do anything with the case. Since my friend who is going to do the machining lives out of state, I want to be able to provide accurate measurements to him. So I'll definitely test the switch in my proposed location.

If everything thinks I will have a problem with this idea though, maybe I shouldn't order my nice, and expensive, chrome switch with an LED in it. If I end up putting the power switch on the back, then there's no point using the fancy one

So you don't think running the wire inside some braided copper shielding would help? My plan was/is to run it down the side of the enclosure. I'll try using one of the upper slots and see if that helps.

Anyway, Mouser got back to me on my question, so I placed the order for the rest of my parts. Everything is coming now except the tubes. I'm still undecided on what tubes to get or where to source them. Right now I'm leaning towards Parts Connection.
post #423 of 1686
Thread Starter 
It's hard to say if you will have problems. If you shield the power wire and keep it well out of the way under board it might work out alright. If you do an RMAA on the amp you may see 60Hz, but it may be at such a low level that you never hear it.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #424 of 1686
I was wondering if anyone has built one of these with the tube sockets on top of the board, but all other components underneath. I've seen folks mention this, but has it actually been done?

I'm thinking about doing it this way, but my concern is that it will no longer fit in the Hammond case if it is done this way.

Also, I'm going with the 50VA Avel transformer, so I know I need more than the standard 1" heatsink for the H- regulator. Will a board mounted 1 1/2" heatsink be sufficient, or will it really need to be a case mounted heatsink?
post #425 of 1686
Quote:
Originally Posted by TimJo View Post
I was wondering if anyone has built one of these with the tube sockets on top of the board, but all other components underneath. I've seen folks mention this, but has it actually been done?

I'm thinking about doing it this way, but my concern is that it will no longer fit in the Hammond case if it is done this way.

Also, I'm going with the 50VA Avel transformer, so I know I need more than the standard 1" heatsink for the H- regulator. Will a board mounted 1 1/2" heatsink be sufficient, or will it really need to be a case mounted heatsink?
Ive thought about this and the concern I have is that now the pins are mirror reversed and not in their original orientation. I am also curious if anyone has actually implemented this plan to see how they tackled that issue.
post #426 of 1686
Ferrari has done this. Search the thread for his posts. He has built 1 with air wired sockets mounted on a support and another where all the tall components are mounted on the bottom of the board. One of the nice features of Alex's design is that there are 2 sets of holes for the transformers that allow you to mount devices with reversed pin outs, or in this case, flipped upside down on the board. The other devices with more then 2 leads (opamps and transistors) are pretty short, so you could still get most of the tube to stick out of the case. Assuming that's your goal
post #427 of 1686
Quote:
Originally Posted by Hayduke View Post
The other devices with more then 2 leads (opamps and transistors) are pretty short, so you could still get most of the tube to stick out of the case. Assuming that's your goal
That is the goal.

I'm just trying to weigh the pros and cons of doing it this way vs. air wiring the tube sockets.
post #428 of 1686
When building the amp with all the tall parts "upside down", be sure to pay attention to good ventilation as I pointed that out in an earlier post.
post #429 of 1686
When running power lines under the PCB, move it to the side. Don't run it underneath the tubes in particular. I run mine underneath, but move it to the side. I have more room in my case than the BOM case, but what may help is if you can run them in the "slots" of the Hammond case. Or go up, to the side, over and run them towards the top of the case.

I actually found I had more noise from the LEDs for the tubes underneath the PCB as the lines were closer to the PCB.

I am using 1/8" spacers. YMMV with taller spacers.
post #430 of 1686
Quote:
Originally Posted by holland View Post
I actually found I had more noise from the LEDs for the tubes underneath the PCB as the lines were closer to the PCB.
Hmm. wonder if this may be a possible source of the mysterious noise some have heard? Any purists built without LED uplighting? I have LED wires and lines for test jacks running under mine (I run audio and power along the sides as a best practice as Holland suggests). I'm finally about to start work on my high-current version, so I'll be able to A/B soon.
post #431 of 1686
I removed the LEDs on mine. It was just a prototyping thing when I was running it without a case. When I cased it, I found I had noise, and promptly removed the LEDs. The reason is that I am using 1/8" spacers. I would imagine with 1/2" spacers, I would be OK.

I do have buzzing on mine. I scoped it briefly and I seem to be getting some noise through to the output. It's hard to tell if it's ground noise or if it's from the PS, but it did look like some noise from rectification. I never did find out why, but it's very hard to hear with headphones and since I have some tinnitus it's very hard to hear it through the ringing. I can hear it with IEMs, but that's about it.
post #432 of 1686
Quote:
Originally Posted by holland View Post
When running power lines under the PCB, move it to the side. Don't run it underneath the tubes in particular. I run mine underneath, but move it to the side. I have more room in my case than the BOM case, but what may help is if you can run them in the "slots" of the Hammond case. Or go up, to the side, over and run them towards the top of the case.

I actually found I had more noise from the LEDs for the tubes underneath the PCB as the lines were closer to the PCB.

I am using 1/8" spacers. YMMV with taller spacers.
Thanks Holland

I am going to try running the wire in the top left (looking from the front) case "slot".

What slot do you have the board in using 1/8" spacers?

Quote:
Originally Posted by wiatrob View Post
Hmm. wonder if this may be a possible source of the mysterious noise some have heard? Any purists built without LED uplighting? I have LED wires and lines for test jacks running under mine (I run audio and power along the sides as a best practice as Holland suggests). I'm finally about to start work on my high-current version, so I'll be able to A/B soon.
I ordered some various LEDs, but I'm probably not going to use them.

A co-worker friend brought up a good point. He asked me, "does it improve the sound?" I answered, "no." He replied, "I wouldn't bother with anything that didn't make is sound better."

There is wisdom in those words, but there is also something to be said for aesthetics. If you don't hear any noise, I say use them. If you do hear noise, then remove them. I sure as hell don't need pretty lights at the expense of SQ
post #433 of 1686
Why not use the usual Digikey 35VA Amveco transformers? Will they not fit the standard Hammond enclosure?
post #434 of 1686
Quote:
He asked me, "does it improve the sound?" I answered, "no." He replied, "I wouldn't bother with anything that didn't make is sound better."
It doesn't improve the sound in theory only.
post #435 of 1686
Quote:
Originally Posted by Hayduke View Post
Thanks Holland

There is wisdom in those words, but there is also something to be said for aesthetics. If you don't hear any noise, I say use them. If you do hear noise, then remove them. I sure as hell don't need pretty lights at the expense of SQ
Agreed, but I'd say aesthetics has quite a bit to do with DIY, but that's probably another thread (where perceived percentages of 'better' SQ are discussed). Otherwise all our builds would remain strapped to boards, and they'd be a heck of a lot quicker to finish!
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