Help Please
Does the F5 turbo need a high gain pre amp? I have very faint audio with my adcom pre amp hooked up
Does the F5 turbo need a high gain pre amp? I have very faint audio with my adcom pre amp hooked up
I don't think so. I was using mine with a mesmerized buffer (gain=1) with power hungry speakers. They played loud in a room 15 x 22 ft. Something is not right. Is your amp getting hot? measure the voltage across the output resistors, what are yo getting?
The F5 has fairly normal gain. If you are only hearing a very faint signal, something isn't right.
Please post a good number well-lit, in-focus photos of your amp and we'll start the de-bugging process 😀.
Please post a good number well-lit, in-focus photos of your amp and we'll start the de-bugging process 😀.
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First guess, when you put together the front end board, the one with the the 170/74 jfets, did you connect "ground" and "link" with a piece of wire?
Ground link
I have a input jack that has a ground, should it be grounded to the case and not in the ground hole?
I have a input jack that has a ground, should it be grounded to the case and not in the ground hole?
Well somehow the gate resistors in all my boards ended up being 100 ohm looked back at my order from digi key and I ordered 47.5 ohm, found the plastic bag they sent it said 47.5 ohms but the resistors are 100 ohm, so that’s my main problems darn transistors are not turning on. Trying again 😬.
One more question the link part, should my ground on input be connected to the case and not to the ground hole? When you said single ended , I thought that meant a input that had no ground.
None lol the gate resistors are 100 ohm and not 47.5, first mistake I’ve ever seen digi key do. I hope there wouldn’t be other problems caused by trying to run it like that?
Do you have an input jack that has two conductor connections, i.e. Signal Flow/Hot and Signal Return/Cold?
or
has it got three conductor connections, i.e. Signal Flow/Hot, Signal Return/Cold and chassis/enclosure?
your previous post and this one show that your use of the "ground" word is confusing you.
I suggest that each time you read "ground" you work out what the Designer/Builder actually meant and ascribe the correct term for that connection/terminal/wire/trace.
The "ground" word gets misused a lot and for everything and as a result it causes much confusion.
Try to avoid that confusion.
It only has 2 connections, it’s the one that comes in the kit from the Diy audio store, the deluxe kit
Then your two connections must be Signal Flow/Hot and Signal Return/Cold.
Neither of these SIGNALS get connected to the chassis/enclosure.
Neither of these SIGNALS get connected to the chassis/enclosure.
Sorry I don't know that PCB and I don't have one to check where that G pad goes.
But (I'm guessing) it looks like the two adjacent pads are both INPUTS, left = Signal Flow/Hot and middle = Signal Return/Cold.
I have no idea why the PCB layout designer labelled it "G"
But (I'm guessing) it looks like the two adjacent pads are both INPUTS, left = Signal Flow/Hot and middle = Signal Return/Cold.
I have no idea why the PCB layout designer labelled it "G"
Don't change them. 47.5 ohm is too low a value for gatestoppers on this amp, I suggest closer to 200, and have used as much as 680 with no issues. Keep the 100ohm in place.
Single-ended = RCA jacks, Balanced = XLR
The center of the RCA should go to the "in" pad on the front-end board, the outside of the RCA attached to the "G" next to "in", the metal of the RCA should not touch the chassis, and the "G" and "Link" should be connected as in the above photo.
You keep saying that. The transistors turn on by setting the bias properly, not by seeing an input signal.
Have you set the pots and measured the bias? Is your amp warm?
I'll suggest that you read Jim's instructions on how to make the initial adjustments, be patient with it, it takes time to bring it up to steady state or thermal equilibrium. You do best if you have 3 volt meters, one for each board (N and P) and one to check DC offset at the speaker output. It's exciting to see the amp working but you really have to take the time to make sure all is good so all the work pays off. Don't connect anything to it, you could ruin your speakers. Build a light bulb cord, do the grounding isolation for your power supply. Do not mix the audio/signal ground with the chassis ground.