Zenductor

[indra1]

You may blame me for anything you deem to be dumb, but the proof of the pudding is in the eating.

Right, we won't blame you if no enough pudding for everyone during BAF.

 

[Zen Mod]

 

[Nelson Pass]

"Perhaps DC bias and AC feedback can be separated, as per the lower LazyCad schematic?"

I don't think there's enough time to get this change onto the B.A.F.2023 PCBs and to purchase the new parts, in time for the Build Camp just one month from now (??)

You would have to (a) obtain approval from the BAF committee for the change; (b) lay out a new PCB with the changes; (c) get the PCB fabricated with expedited shipping; (d) order all new components and have them shipped to the right people, well in advance of BAF; (e) create new schematic and parts list and build guide

while time is short.

Actually there is still time to offer suggestions to the pcb art, but it has to be today. Parts are not a problem and the "committee" consists of Mike and me. However, understand that the T shirt schematic is a simplification of the actual circuit and some of the issues mentioned have previously been addressed.

 

[Michael Rothacher]

PSRR is better with the speaker ref to signal ground, providing there is not some other reason for wanting it where it is (proto was reasonably quiet either way though). C4 and R7 don't really do much. More to follow when I get back from my flying lesson.

 

[Michael Rothacher]

FB and bias are already separate, but not shown in the T-shirt art.

 

[andynor]

Actually there is still time to offer suggestions to the pcb art, but it has to be today. Parts are not a problem and the "committee" consists of Mike and me. However, understand that the T shirt schematic is a simplification of the actual circuit and some of the issues mentioned have previously been addressed.

That T-shirt version, is it just me, or there a hint of JJ there?

 

[tonyEE]

Actually there is still time to offer suggestions to the pcb art, but it has to be today. Parts are not a problem and the "committee" consists of Mike and me. However, understand that the T shirt schematic is a simplification of the actual circuit and some of the issues mentioned have previously been addressed.

Hey! If we built the amp... do we get a T-shirt too?

 

[Zen Mod]

give them hand, they demand the arm

 

[Michael Rothacher]

No whales, but we have dolphins!

 

[andynor]

Getting any feedback from them? Guess that would be PCF.

 

[Michael Rothacher]

They said "So long, and thanks for all the fish."

 

[Michael Rothacher]

Ok, let's see:

Vgs turn on event looks ok, Vgs turn off event looks ok.

Turn off thump is minus a couple V / 20ms. Turn on thump fine.

If spk ref is changed to signal ground, then C3 filter cap should be across full B

Probably, we'll get a little pop when shorting the input, e.g. preamp mute or select

That's all I can think of without being home with the real things.

 

[BRN]

I like the idea of graphics of your favorite NP, ZM, MR, MJ, and WC designs on t-shirts. Did I forget anyone?

 

[Tom V]

Hey! If we built the amp... do we get a T-shirt too?

Short answer: No. Slightly longer answer: I made the command decision to eat the Eventbrite fees this year, so we are a bit underwater with the Material Fee, so no room in the budget to include a t-shirt.

However Brian (bhjazz) is putting the final touches on a t-shirt design and I will have them on sale shortly.

-Tom-

If you are busily designing based on the t-shirt circuit, know that the real circuit has two pots in it. One sets bias, one does.......something else.

 

[tonyEE]

There is NO reason why you should be short.

None.

Just ask.

I'd be more than glad to put some money where my mouth is ( and it's a big mouth... ).

Thank you all very much for putting this up.

Hmm... being this is a NorCal design with two pots... does it have a bong too?

 

[Michael Rothacher]

Perhaps, PassDIY can offer merch in it's "Shameless Commerce Division".

 

[Tom V]

There is NO reason why you should be short.

Don't worry, I expect this year's BAF to finish solidly in the black.

The $150 Material Fee reflects the magnificent generosity of Nelson Pass and his incredible, never-ending parts bins in which stock levels are rounded to the nearest 1000.

-Tom-

 

[Tom V]

To all of those busily designing your Zenductor variations, bring your "maybe this" and "why not's" to Mike's Saturday Spicy (LT that is) seminar and he might explore some of them with you.

-Tom-

 

[Nelson Pass]

PSRR is better with the speaker ref to signal ground, providing there is not some other reason for wanting it where it is (proto was reasonably quiet either way though). C4 and R7 don't really do much. More to follow when I get back from my flying lesson.

The reason we put the speaker across the inductor is that it looked cool. Running the positive output to
circuit ground gives the same performance, but has one advantage which is that the output terminal doesn't
have live DC. I also dropped a capacitor, a pot, and a couple resistors.

No more suggestions, I am sending the art out for fab before it gets late.

 

[Michael Rothacher]

It did indeed look cool, and it was perfectly great.