50w Single-Ended BAF2015 Schade Enabled

[Soundhappy]

Any issue with installing the 4N37 from the underside of the PCB in a point to point setup?
When upside-down, the 4N37 pins match the schematic perfectly. I don't think it would cause a dissipation issue, but thought I'd ask.

thanks,

Vince

Me too I think installing the 4N37 in underside position is not an issue 🙂

 

[vdi_nenna]

Thank you!

 

[Soundhappy]

Great Vince Enjoy this build!
What Your transformer choice model at the audio input ?

 

[vdi_nenna]

The Jensen, because I've had a pair for a long time.

 

[Soundhappy]

Big YES for the Jensen's quality 🙂
My as well is point to point soldering made amp.
Next step is to try all technology
: carbon, mox, metal film, wire wound, bulk foil, etc.
rolling of 220R 3 Watt's feedback resistors, 22R at the drain and
if I get another input transformer just for the pleasure to hear the difference in acoustic instruments tone fidelity.
BTW IXYS price go up

 

[vdi_nenna]

Must be worth the effort. 😉

 

[Soundhappy]

I agree and it's easy amp " sound tuning " for the particular speakers pair.
Please Vince post us Your Schade amp construction report 🙂 Have fun

 

[vdi_nenna]

If I were to lower the voltage of the circuit from 60v to 40v, would the drain of the mosfet be at half the circuit voltage, e.i., 18v-20v?
Is this similar to the ACA bias adjustment? Would I then monitor the drain voltage while adjusting the bias at the gate, arriving at around ~20v?

Thanks,

Vince

 

[Zen Mod]

yup

goal is to have symmetrical behavior of amp's output , in voltage domain .... thus resulting in highest possible power (from voltage window) ..... finally resulting in so-so symmetrical clipping

 

[vdi_nenna]

Great! Now I feel better about starting the project. 🙂

 

[vdi_nenna]

220R 3 Watt's feedback resistors, 22R at the drain

Happy, is the 22R, near the 220 3W, a 1/4w resistor?

I'm starting to piece parts together tonight. Finding I'm missing a few parts.
More orders. 🙄

thanks,

Vince

 

[Soundhappy]

Hi Vdi_nenna

22R is 1/4 watt 220R / 3 watt's minimum little bigger is always ok 🙂

 

[vdi_nenna]

As always, Thank you very much!

 

[Soundhappy]

Missing parts is for Papa TL431 bias curcuit ?
Work like a charm 🙂

 

[vdi_nenna]

Are you using this circuit for the bias section?

 

[Soundhappy]

Big YES is perfect for the IXYS bias inside the Schade 50W 🙂
Multiturns trimmer for voltage precision.
Zen Mod version if made with other resistors values.
Schematic courtesy of Mighty Pumpkin

 

[Soundhappy]

Are you using this circuit for the bias section?

How much of the bias for Your mosfet ?

 

[vdi_nenna]

Good question. Will be using a IRFP250. I believe it's based on how much voltage will appear at mosfet drain, which is around 18-20v, depending on symmetrical clipping. Not sure what the figure will be. Will have to monitor it while adjusting.

I have a prebuilt LM317 circuit to speed up the build process. The transformer has extra 12v and 18v secondaries, so voltage is not a problem.

 

[Soundhappy]

Cool Vdi_nenna build with H2 , H3 switch on the CCS ?
Between D and C 0.1R resistors connection points.

Me ask swap IXYS to SIT: 2SK180, THF-51 or 2SK182ES.
Mr Pass use 2SK77B any datasheet available to compare with similar Tokin's ?
FAB like experiments but not rare triode sand smoke 😀

 

[vdi_nenna]

Cool Vdi_nenna build with H2 , H3 switch on the CCS ?
Between D and C 0.1R resistors connection points.

I'm not that adventurous. I'm going to keep it simple, keep it as-is.