[jtwrace]

Also know as Unibit...It works but is a crude way to drill a hole.  You really need to file after to get all the burrs off.

[wushuliu]

oh, excellent. I think I found a unibit that will work perfect. I'm pretty sure I have a file in my tool box, so should be good there. thanks much!

[jtwrace]

oh, excellent. I think I found a unibit that will work perfect. I'm pretty sure I have a file in my tool box, so should be good there. thanks much!

    Measure twice or as many times as it takes to get it right the first time.  Masking tape or painters tape works best.  Tape the surface to be drilled then use a fine tip Sharpie to mark before drilling.  Of course using a center punch then drill a small pilot hole ~1/8" then use the Unibit.  This will keep the Unibit from "walking".

[roymail]

I put some masking tape where I want to drill, mark it clearly, then use several small bits to work up to the hole size.  Making a pilot hole is a must, and go slow.  Good bits help a lot, worn bits don't work well.

But, that said, it's not hard to do... get 'er done!

[Mariusz]

Yeah, small half-round file might be needed.

[roymail]

Looks like Jason and I had the same things to say while we were typing at the same time. 

This is just me, but I'd stick with regular drill bits to do this simple job.  Don't really need a "step-up bit."

[jtwrace]

Looks like Jason and I had the same things to say while we were typing at the same time. 

Great minds think a like.   

[wushuliu]

Terrific! Thanks guys. I'll probably take pics and write it up, of course...

[inept]

I'll second the step drill bit.

I've used regular drill bits, small one for pilot hole and 1/2" I think for the final hole for binding posts, and a stepped drill bit.

The stepped bit was much faster and cleaner,...just be sure to mark the bit where you want to stop, i wrap a piece of tape around the step just above the size I need.

[avionic]

The par metal cases are very easy to drill,cut etc. I used a punch and regular drill bits. Smaller for pilot holes then stepped up to size needed. As already mentioned masking tape and draw everything out with a pencil or something else eraseable. For the IEC outlet you can use a skill saw with a metal cutting blade. Works like a champ. When your done cutting and or drilling you can clean up the holes with a file or sand paper as the metal is fairly soft.

[wushuliu]

Well the new amp board is up and running and everything seems okay . I'll be ordering the Par-metal in  a couple days...

[Nick77]

Well the new amp board is up and running and everything seems okay . I'll be ordering the Par-metal in  a couple days...

Great news! Glad your PS survived the storm.

[cynan]

Earlier in this thread someone was asking for opinions of going with one of the linear PSU boards at connexelectronics.com over the one offered at classDaudio.com. I don't think anyone addressed this. Unfortunitely, I can find very little info about them on the website. Does anyone have an opinion about either of these modules with the SDS-254 or SDS-258? Would the combined 60,000uf capacitance of these be any sort of an upgrade?

http://connexelectronic.com/product_info.php/products_id/69?osCsid=3prbrltmu15kfebq69if854uf2

http://connexelectronic.com/product_info.php/cPath/25_45/products_id/87?osCsid=3prbrltmu15kfebq69if854uf2

wushuliu, what size of par-metal case would you be considering? 12x12x4 or 12x16x4?

[roymail]

Hi guys,

OK, there has been some confusion about the input impedance of the CDA and SDS amp boards.  I want to thank Deward for his technical help and Tom for giving me a more complete explanation as to why some boards measured differently than others.  Here is the email I received earlier today.  I'm posting it with Tom's permission.

Hi Roy,

I’m sure there is some confusion on the impedance of the CDA series amps. They have gone through changes since out first design. Our first amps worked well with most preamps and input devices, but they did have very low input impedance, and some with tube preamps had problems. Since that time, we have made several changes to try to make them more compatible and able to match up well to all available input devices. We have used up to 45K, but now we have settled on 7.5K input impedance for the CDA series. This seems to match up very well with all available audio equipment so far, and keeps the input noise down to a minimum. The SDS amps have an input impedance of 45K in balanced mode, and about 42K in single ended mode. This seems to work great with these amps and the balanced input stage. For some time now, we haven’t heard of any problems matching our amps to other input devices.

I hope this helps shed some light on this topic. Please let me know if I can be more help.

Thanks,
Tom

[Nick77]

Earlier in this thread someone was asking for opinions of going with one of the linear PSU boards at connexelectronics.com over the one offered at classDaudio.com. I don't think anyone addressed this. Unfortunitely, I can find very little info about them on the website. Does anyone have an opinion about either of these modules with the SDS-254 or SDS-258? Would the combined 60,000uf capacitance of these be any sort of an upgrade?

http://connexelectronic.com/product_info.php/products_id/69?osCsid=3prbrltmu15kfebq69if854uf2

http://connexelectronic.com/product_info.php/cPath/25_45/products_id/87?osCsid=3prbrltmu15kfebq69if854uf2

wushuliu, what size of par-metal case would you be considering? 12x12x4 or 12x16x4?

I dont have any advise on the supply in question but several of us have gone with just swapping out the stock Nichicons with Panasonic tsha series with positive results. It is not clear whether the increase in capasitance was the reason or the better caps. In both cases the increase was to 40,000uf and hasnt been confirmed if going higher is of any value or not.

[cynan]

what happenned to the half dozen posts that were posted after this today?

[jtwrace]

http://www.audiocircle.com/index.php?topic=81224.msg779312;topicseen#new

[wushuliu]

what happenned to the half dozen posts that were posted after this today?

Split off this thread, for those feeling a little, er, Lost. No merging back. Whatever happened, happened. 

[Mariusz]

jtwrace

some members feel the need to expend on the topic and more techical side of it, including modifications etc. Ones we start moving away from the original topic and essence of this thread it will become more & more confusing for new readers.
We are already covering more then few versions of this amp and I see that it might look a bit "loose" for someone who just started fallowing this topic.
It will be also easier to refer future questions to coresponding thread in appropriate circle.

Mariusz

[mcgsxr]

I had been considering building one of these kits up as a sub amp, but the simplicity of the BASH 300 for $175 shipped to me in Canada won out in the end.

I will keep my eye on this thread though, as I may in time move away from my 96db efficient OB speakers, and look for affordable, good power - these appear to deliver that in spades!