The Singing Bush Tips 'n' Tricks

[asphalt]

I followed Zen Mods advice as well
With baby sitters Hottest part is 50-53
Degrees C

 

[codyt]

When you get a chance, could measure on top of the 77B's (the PCB I mean) and see what the difference is from that hottest spot?

*edit* nevermind, as I imagine if the babysitter is blowing through the inside of amp, the device temp would be about same as heatsink

 

[Zen Mod]

gun thermometer thingies are good, but you can't be precise with position of measurement ( maybe costliest ones are having controlled or no paralax between readout point and "lazer" thingie)

what I'm using is NTC probe, got with DMM - precise enough, with tiny blob of thermal goop on tip, you can sense tiny point

I'm probing - as most critical point - exactly at line between part base and heatsink

you can also lean on Drain screw, or ditto on part base plate, near one of screws

10deg difference between heatsink near the part and part itself is ..... too much

anyway, Cute Babysitter can make wonders to your Childhood

 

[codyt]

Ok, sounds like I'll be slinging some goop and buying quiet fans soon 🙂

Thanks for your help!

 

[Zen Mod]

for me - easy enough to scavenge dead PC PSUs with 12cm fans
fan cleaned and lubricated is silent at 7-8V

sleeve bearings, usually quieter than ball bearing; even with hours in my workshop, I still didn't do any maintenance of fan for Papa's Koan

 

[codyt]

That's good info. I tried making one last year, but I ordered too small a fan. Definitely need the 12cm

 

[asphalt]

I measured 46 C on top pc board of SK77B
I measured 55 C on heat sink right behind where SIT bolted
Immediately adjacent fins were 50 C
The puck measured close to 60 C on board and 55C behind it on heat sink dry

 

[codyt]

Thanks for measurements!

On another note, is it accurate to say that this amp inverts polarity?

 

[Zen Mod]

yes

who cares

try both ways, leave preferred one

 

[twitchie]

Amazing, super tidy build Cody! Very much deserving of fugly!!!

You did justice to the 2SK77B.

Cheers,
Stephen

 

[codyt]

Thanks Stephen! I'll have one more round of glamour shots and some details when the front plates arrive. I went with something like the Sony DIY amp. Should look nice.

ZM, exactly, who cares. I was just curious. It sounds superb any which way you switch it 🙂

 

[poseidonsvoice]

Wow! Ace builder we've got here. Very tidy, and clean with all the right parts in all the right places (especially Toroidy😉 ); thanks for posting the spectra too.

Best,
Anand.

 

[codyt]

Thank Anand! Yes, this was my first time using Toroidy. I’m VERY impressed. They were happy to do custom work too, which was welcome.

 

[codyt]

Finally got the monoblocks finished up. New faceplates and some minor wire rerouting. Also swapped the interface material under the transistors with some thermal grease. That change plus the trial babysitters I constructed have made a huge difference. Thanks for the recommendation ZM!

Front plates are a play on the recent Sony DIY design. Went with a green led indicator in tribute to ZM 🙂

 

[jwjarch]

Beautiful work Cody! Listening impressions?

 

[Zen Mod]

Finally got the monoblocks finished up. .....

Fugly!

...... made a huge difference. Thanks for the recommendation ZM!.........

as I said in some other thread ..... De Nada

I'm here to serve and protect and show that Mine is Biggest in The World

.......tribute to ZM 🙂

to whom else?

lets just ignore that entire shebang is blatant copy and exploit of Papa's

 

[codyt]

Thanks jwjarch! It sounds incredible. Has the SIT magic and some major cajones in the lower end.

ZM, since I didn’t put ‘Singing Bush’ on the front, I at least wanted to hat tip you with a green led 😀

 

[Zen Mod]

I don't care

You can write >put hereanyhornyaudiophoolname< at Fascia ........

 

[flocchini]

Cody
Absolutely top notch build.
Enjoy the music !!!
Bob

 

[Botte]

Sweet!

Nice work!