No, 😉 I found some high quality 20V / ~200Va surplus toroids so I bought a small pile of them for 10 bucks each.Dougie085 said:
I used my "dead-short" reading as "0". Subtracting that number from my final reading. It was the best I could do 🙂flg said:
I'm heating up the iron now...
7/10
Oh and Magura, Incredible!, for what application?
Dougie085 said:
This isn't an SE, but a PP Class A amp of a mere 25W/8 continuous.
With a constant power draw of <65W you can easily get by on a decent 160VA without any hum.
A common 160/180VA toroid is roughly 1/3" less high than a 225/250VA but has an identical outer diameter, there's hardly case dimension saved with the little one.
A 250VA has 1% better regulation, no benefit there as a rail level of 24Vdc requires 35V caps anyway.
Price tag difference for the 250VA is less than $10 extra, for a few bucks more you get less rail sag and a lower donut temperature.
My Papa sez 6 Amps continuous : 6A x 18Vac x 2 is less than 250VA.
Much higher than the 250 is somewhat irrational as a single-pair output stage only handles 300Watts dissipation Max.
Me rule of pinky finger is not to pick a PS with more continuous spunk than what will kill the output stage.
So the F5 does 25W/8ohms? Does it change much at 4ohms? My friend that originally showed me it had said it was like 50watts but maybe that was 4 ohms or maybe he just figured it wrong? Could you use 2 amp boards and run them balanced to get more power? Or would it be better to just add more output devices? Or maybe your just talking in general 😀 I'm not really sure how to figure out watt output or what not.
Ok thats what I thought. Does it change much at 4ohms? Or is that about the limit of a single pair of devices?
You'll have to change the thermal protection circuitry...why not spring for a subscription to AX?
I would but no extra money at the current moment 🙂 So if I ever run 4ohms I have to change the design of the amp?
So would it be possible to use 2 amp sections and run them balanced or bridged whatever you want to call it. Would this degrade sound more then just adding extra output device sections?
Just a note:
I will not send etching files to people that are not posting on this thread so just chip in and let us know you.
BTW, the etching files do have some mods including space for screw holes for board fixing and they are 1:1 scale when properly printed, the file shown on post 344 is not to scale.
I will not send etching files to people that are not posting on this thread so just chip in and let us know you.
BTW, the etching files do have some mods including space for screw holes for board fixing and they are 1:1 scale when properly printed, the file shown on post 344 is not to scale.
Good point Tony
This is a cooperative discussion regarding the project. I do not think it is reasonable to jump ahead and bypass the mag. article. I am waiting for my copy of AxP to show up so I can offer some useful discussion, observation, or questions.
I am in 100% agreement with NP that it is important to support AxP magazine.
Once the mag. has been out for a while discussion will proceed at full speed.
Be patient there will be lots of interesting discussion
This is a cooperative discussion regarding the project. I do not think it is reasonable to jump ahead and bypass the mag. article. I am waiting for my copy of AxP to show up so I can offer some useful discussion, observation, or questions.
I am in 100% agreement with NP that it is important to support AxP magazine.
Once the mag. has been out for a while discussion will proceed at full speed.
Be patient there will be lots of interesting discussion
I second that. No sense arguing over or even discussing items that Nelson already covered in the article.
and lets not kid ourselves,
if you really "...can't afford..." the magazine, you probably shouldn't be worrying about which components to use building this amp...
my 2c
Stuart
if you really "...can't afford..." the magazine, you probably shouldn't be worrying about which components to use building this amp...
my 2c
Stuart