[runeight]

Do you mean TPL and TPR measured with respect to ground? Or measured with respect to the B+?

 

[ChrisX]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif Do you mean TPL and TPR measured with respect to ground? Or measured with respect to the B+?

With respect to TB+L/R.

Chris

 

[runeight]

OK. At least everything is working properly.

These voltages are abnormally far apart because the two tubes that you happen tohave are mismatched in totally different directions. They are acceptable voltages, but it would be better find two tubes that gave you closer to the 19V design point.

 

[ChrisX]

Alex, Thanks for your diagnosis. I checked the first plate of the tubes (Pin 1) and there are the expected 19 Volts. So it's really only that my tubes are mismatched. I have four of them so I will try the others and stick with the best ones.

Seems I have "luck" with mismatched parts. The 7815 in this SOHA_II delivers 14,8 V, the 7915 -15,3 V.

Chris

 

[zkool448]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif This setup is ok but it offers more opportunties for noise and hum since the amp won't be grounded to a nice big piece of metal.

Thanks Alex, i took apart an old cd drive casing for use as my bottom ground plate

Quite happy with the casework so far but I'm having trouble deciding which wood stain to use (cherry vs. red mahogany)...

 

[zkool448]

Added above some pics of dry fit.. that is all for now until later this week, I'm now off to an easter turkey dinner!

 

[onform]

That is some serious example of what can be achieved when you have the tool's and the know how...well done

 

[zkool448]

Thanks onform. The wood case and the top/bottom "lids" must've took about ~8-10 hours to build and finished sanding. Tube holes still need to be cut and still waiting for a few mouser parts (jacks, switch).

I dread the staining part, I'd be really disappointed to screw this up at this point.

 

[smeggy]

Well it already looks damn pretty zk, really looking forward to the end result... I predict awesomeness

 

[jonoliew]

was wondering how this amp faired against the woo audio 6se or wa2? I'm thinking of building one after seeing all your beautiful works of art! ahaha

 

[Ferrari]

Very nice zkool448, really creative with wood.

I’m also busy with the casework for my balanced SOHA II, but no wood from this side of the ocean.
It’s a 2 boxes solution…. the amp is feeding by 2 oversized transformers, 80VA each.

 

[adamus]

I spy an e24.

looks really good ferrari, i shudder at the cost! Schaeffer isnt cheap these days.

have you got any idea of what tubes you are going to use in it?

 

[ChrisX]

Quote:

Originally Posted by zkool448 /img/forum/go_quote.gif Added above some pics of dry fit..

Really Beautiful.

But I would be a bit concerned about ventilation. I finished my SOHA_II this week and still without any enclosure the heatsink temperature reaches 60 °C (with a few mA below the recommended bias of 100 mA), R3P yet reaches a few degrees more. And now it's spring not summer. Therefore I already changed my enclosure plans and sure will follow Alex' recommendation of a more than 50% open top plate. If I knew before I sure would have bought higher heatsinks (1.5") and accepted a resulting higher enclosure.

Chris

 

[wiatrob]

Quote:

Originally Posted by Ferrari /img/forum/go_quote.gif Very nice zkool448, really creative with wood. I’m also busy with the casework for my balanced SOHA II, but no wood from this side of the ocean.

It's sloooowly taking shape! Nice to see..

I should post some pics of my latest 'II - it's in the case phase but ZK's wood and your metal work makes me a bit embarrassed to show mine.

Darn DIY'rs continually raising the bar...mumble mumble...

 

[Ferrari]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif I spy an e24. looks really good ferrari, i shudder at the cost! Schaeffer isnt cheap these days. have you got any idea of what tubes you are going to use in it?

Yes, the ε24 circuit is on board.

Since the heater power supply circuit on my amp is modified a bit: based on LM338 (instead of LM337), feeding by an 80VA transformer separately, I’m thinking of trying some current hungry tubes like 6N1P, 6N6P and 6N30P...