• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Mullard 5-20 KT88 PP blocks!

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#704
taj said:
I just want to confirm that you want to eliminate the smaller inductor and the 1000pF cap in the power supply? And I assume the thermistor stays.

..Todd
Click to expand...


Leave them in.....the thought never occurred to me to include them in the model. Which brings up a question, what's the estimate for the DCR of the small inductor? Hopefully that won't reduce B+ too much.
 
#705
boywonder said:
Leave them in.....the thought never occurred to me to include them in the model. Which brings up a question, what's the estimate for the DCR of the small inductor? Hopefully that won't reduce B+ too much.
Click to expand...

It depends on current handling mostly. (Heavier wire = less resistance.) So 200mA inductor might have 3.5R DCR and 750mA inductor might have 1.5R DCR (based on a quick look at Digi-Key's offerings). Is there some recommended type or model used for this purpose?

..Todd
 
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#707
LW Miller 1.5mH Hash Choke Mouser 542-5900-152-RC. 1.5Rdcr is about right.
When I model it it takes the time slice too small. It doesn't impact lower ripple harmonics, just the higher ones. If you want to accomodate it just add 1.5R to the main choke dcr.
 
#708
The datasheet says DCR is 1.18R max, so 1.1 or 1.2 is probably good for modeling. This choke is rated at 600 mA, saturates at 700.

Are there any other specific, preferred or suggested parts that should be included in the BoM to assist builders? I think someone mentioned a Schottky model for the rectifiers. I'll look for that.

I'd like to include both DK and Mouser part numbers where appropriate, and as many good options for the less obvious parts as possible (transformers for example).

Where subjectivity enters, I'd prefer to list the 'technically preferred' component type (with some examples) so folks can make their own choices. (I'm thinking of the coupling caps here, but that may apply to other parts.)

...Todd
 
#712
taj said:
The datasheet says DCR is 1.18R max, so 1.1 or 1.2 is probably good for modeling. This choke is rated at 600 mA, saturates at 700.

Are there any other specific, preferred or suggested parts that should be included in the BoM to assist builders? I think someone mentioned a Schottky model for the rectifiers. I'll look for that.

I'd like to include both DK and Mouser part numbers where appropriate, and as many good options for the less obvious parts as possible (transformers for example).

Where subjectivity enters, I'd prefer to list the 'technically preferred' component type (with some examples) so folks can make their own choices. (I'm thinking of the coupling caps here, but that may apply to other parts.)

...Todd[/QUOTe

Sounds like a fine plan.
Click to expand...
 
#714
Taj (your reply #701),

Yah! Had that sinking feeling I was behind somewhere - perhaps a new pair of spectacles needed. Thanks for the update.

SGregory correct about cap voltages. C5 could be 100Vdc, being in a resistive attenuator. L1-C2 should definitely remain but will have no effect on PSU modelling. Small voltage drops like that are irrelevant; the daily mains variation will probably be more.
 
#716
Turns out Nocturne is a model of Harman Kardon amplifier. But very old (from the 60's by the looks of it.) I don't think that would be a big trademark issue, but someone may think this project is a revival of that amplifier, which it isn't.

..Todd
 
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#718
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