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July 22, 2024, 07:59:54 AM

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#1
Honey Amp / Re: Transformer Question
Last post by J M Fahey - July 21, 2024, 01:21:01 PM
A rectifier, including a bridge, will charge supply capacitor to 1.41X AC voltage, so about 24VDC as stayed above.
You can* down regulate it to 16V or whatever this mini amp needs.
Simplest is using a 7815 and a diode or two to rise voltage reference, or use an LM427 which costs cents more and is fully adjustable.
You will need some heatsinking for the regulator , at least of aluminum sheet or rail
 
#2
Amplifier Discussion / Re: What happened to music ele...
Last post by J M Fahey - July 21, 2024, 01:12:46 PM
Sadly browser returns "a system error problem has happened. Try again later or repeat last action".
#3
Amplifier Discussion / Re: What happened to music ele...
Last post by Loudthud - July 20, 2024, 08:30:36 PM
The most current info I have is in this thread:

https://www.ssguitar.com/index.php?topic=4868.msg42377;topicseen#new
#4
Amplifier Discussion / What happened to music electro...
Last post by Axtman - July 20, 2024, 05:50:46 PM
The MEF forum appears to be down for about a week. Does anyone know what happened? Thanks.
#5
Amplifier Discussion / Re: Bipolar PSU PA + single PS...
Last post by J M Fahey - July 18, 2024, 07:48:24 PM
Think that the power typically takes full Amperes, say 2 - 3 - 5 Amperes, even more on a 100W amplifier.

At a preamp level, each signal transistor takes 1 to 5 *milli* (one thousandth) Amperes, an Op Amp some 2 to 5 milli Amperes and so on.

Only those doing (small) power amp jobs such as reverb tank drivers or active earphone out can take, say, 20 to 50 milliamperes.

In any case way less than any speaker driving stage.

So in general, no big deal
 

#6
Honey Amp / Re: Transformer Question
Last post by RookieRecurve - July 09, 2024, 10:23:24 AM
I was under the impression that a full-bridge rectifier would drop the voltage?  I guess too much voltage is better than too little as it should be easier to drop it than to increase it.
#7
Honey Amp / Re: Transformer Question
Last post by Loudthud - July 09, 2024, 02:21:03 AM
After rectification and a filter cap, the output will be close to 24VDC. To get 16VDC, you will need some kind of Voltage regulator.
#8
Honey Amp / Transformer Question
Last post by RookieRecurve - July 08, 2024, 07:30:48 PM
Hi all, I got my kit last week, and was looking at options for powering the amp, and discovered I have a power transformer from an old Dell powered-speaker set.  It outputs 17v AC and 2.5A.  I have a full-bridge DIY rectifier kit on its way to convert it to DC.  I am not sure what the final DC voltage will be, but I am hoping for 16 VDC.  I cut open some shrink wrap on the power supply, and found a 0.1uf 275VAC capacitor in there.  Any ideas what this is for?  It appears to be wired in parallel?  Any thoughts on my proposed power supply?  I figure it's free, and it's great for learning more.
#9
Amplifier Discussion / Re: Bipolar PSU PA + single PS...
Last post by Miyagi_83 - July 08, 2024, 12:28:29 PM
Thanks, g1 (pentode control grid?  ;) )
I'll measure the preamp's current draw and see how much or how little it is.
Have a good one.
#10
Amplifier Discussion / Re: Bipolar PSU PA + single PS...
Last post by g1 - July 08, 2024, 11:54:03 AM
Probably won't matter, depending how small the current is.
If you are really concerned, you could just put a resistor across the negative rail to draw a little current and balance it out.