Hello can somebody help me out i trying 2 find out how 2 get this free 2 build a 1-16 pill amp bim not sure how 2 get these. If somebody know how can u email me at pimpdaddysumo1975@gmail.com. thanks
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Shadetree Mechanic
Delaware Base Station 808
Check out page 6 of this thread, I posted the plans as attachments. I have not tried any of it yet and apparently there is some tuning that needs to be done. This is only a starting point. Good luck.
thank you all off you for posting those plans, I was looking for a 1 pill amp
(found a forgoten mrf454 in my shack) ..time to make some xperiments
greetings from Mexico and happy New Year
(found a forgoten mrf454 in my shack) ..time to make some xperiments
greetings from Mexico and happy New Year
I think the polarity is backwards on one of the input transformers on the 4 pill schematic. But that's not why I'm posting.
What really has me puzzled is why there is an RF choke in all of these schematics BETWEEN the transformer and positive rail pad where the RF decoupling caps are located. Those caps, I assume, are supposed to be between the transformer and chokes, not before them. Texas star has them between the transformer and the chokes. Wouldn't the capacitors circled in green need to be moved over to the transformer?
If that side of the transformer is not at RF ground, but instead has a substantially reactive choke in the way, how is one supposed to put any RF current through it? The capacitance of the transistor in parallel with the cap they have chosen for on the transformer has a 2.92Ω capacitive reactance (using 2879 datasheet) suggesting that the combination of primary inductance and choke inductance is equal to that. Impossible. 2.92Ω capacitive reactance makes sense if the RF bypass caps were to the left of the chokes.
What am I missing? Are these "free designs" meant to cause failures and deter people from building amplifiers? Better question... Who here has ever built one this way and have it work good?
What really has me puzzled is why there is an RF choke in all of these schematics BETWEEN the transformer and positive rail pad where the RF decoupling caps are located. Those caps, I assume, are supposed to be between the transformer and chokes, not before them. Texas star has them between the transformer and the chokes. Wouldn't the capacitors circled in green need to be moved over to the transformer?
If that side of the transformer is not at RF ground, but instead has a substantially reactive choke in the way, how is one supposed to put any RF current through it? The capacitance of the transistor in parallel with the cap they have chosen for on the transformer has a 2.92Ω capacitive reactance (using 2879 datasheet) suggesting that the combination of primary inductance and choke inductance is equal to that. Impossible. 2.92Ω capacitive reactance makes sense if the RF bypass caps were to the left of the chokes.
What am I missing? Are these "free designs" meant to cause failures and deter people from building amplifiers? Better question... Who here has ever built one this way and have it work good?
FC 4,5,6?
Ferrite chokes
In this case
The Chokes allow DC to flow and stops RF (AC) from bleeding back into the b+ rail.
C25,6,7,8,9 and C30 help pull any rf off the + rail.
73
Jeff
I understand that as a general concept, but in this case, the positioning of them is what I question. RF needs a ground somewhere on that side of the transformer. The problem here is that there is a choke between the RF transformer and the capacitors it uses as a path to ground. The current location of the choke is like disconnecting the RF connection on that side of the winding.
The DX 500 had the rf chokes on the other side of the capacitors, and this makes sense to me. There can still be capacitors doing the same thing on the voltage rail before the chokes, for good measure perhaps, but the important thing here is that they also have caps after the chokes so the RF on that side of the winding (brass tube) sees RF ground without the choke interfering.
ShadowDelaware
Well-Known Member
in fact, here are the 4-pill, 5-pill, and 16-pill plans for anyone looking for them as well.
Shadetree Mechanic
Delaware Base Station 808
oh gotcha. well now theyre on both pages 6 and 9 now.