Octal Deluxe

[Lonely Raven]

Now that you got that sorted out, you have a layout or Schematic? I'm curious to see how you implemented the octal preamp tubes.

[M Fowler]

Weber Proluxe maybe?

[Noval_novice]

I think Weber's Octal Proluxe uses grid leak bias. All I did was use the octal preamp tubes without changing the cathode biasing of the 5e3.

Here's a schematic. Be gentle. I am still learning this crap and sure there are errors.

[ChrisM]

Your taking your outputs off the HV B+ instead of the plates.

[Noval_novice]

Sorry. Didn't understand you.

[Cliff Schecht]

Lol he's right, your schematic is wrong. The signal coming out of each tube gain stage should be after the 100k plate resistors. What you have drawn won't work.

[greekie]

What the above gentlemen are saying is, that you should take the signal going FROM the tubes at the tube's plates, and not above it's plate resistors.

Also, the boost-switches you have on the cathodes of the first tubes - install two, say, 100K resistors in series with capacitors C1 and C2, and make the switch short out those resistors. That way you'll avoid some nasty popping from the capacitors not having a steady voltage reference when switched out.

It's OK to be new, don't worry about it, that's what we're here for. Everyone has a question and everyone knows something.

Jake

[Ian444]

Cliff I can't just let that one go. This guy is a newb and said there would be errors. "lol" is hardly encouraging. "your schematic is wrong" doesn't help. He built the amp and it works for fuck's sake. We've all been there, you too. Think about it.

[Noval_novice]

Ok, I see. Yeah, that's not right. I will fix the schematic when I'm done with work today. Looks like I also placed my power switch in the wrong place. I will also add the resistors to the boost capacitors. Hadn't tried placing different cathode capacitors on a switch before. It pops but not loudly.

Ian, no worries. I wouldn't post here if I didn't want to be corrected.

[M Fowler]

Hey you stole my line

for fuck's sake

[Cliff Schecht]

Only reason I said lol is because I looked at that schematic earlier and didn't notice the plate resistor error. It seems my attention to detail has waned since things are getting hectic for me these past few weeks..

[Noval_novice]

Ok, here is an updated schematic. Thanks for everyone's input. I'd be lucky to make anything work without the help from this forum!

[Phil_S]

Really, put a 5K across R24 and R25. This will give you about 4K and 2.4K instead of 18K and 4.7K. You'll get a decent boost in preamp voltage. It will increase your headroom and give you a bit more gain, as well. If you don't like it, you can simply remove them.

[Noval_novice]

I may try that. Thanks, Phil.

[SeppoL]

Ok, here is an updated schematic. Thanks for everyone's input. I'd be lucky to make anything work without the help from this forum!

I gonna making same using your schematic. Are you still happy? Have you changed something? Maybe i try 6SN7WGT phase inverter. And 6AK6 power tubes for bedroom level.

Seppo