If you are talking about F6 kits, 2 versions...one is just boards and transformers, one with same plus all parts needed to stuff PCB except J fets.
There is a list of all parts, and a picture of same...power supply not addressed. The power supply board from store is just a board. Maybe I am misunderstanding? If not, no power supply parts not included.
Russellc
Bummer
So I just did my first power up test of my F6 build and....
Nothing. But no magic smoke or bad odors.
On power up bulb tester lights up and goes to dark in 3 seconds and stays dark.
Led lights on left channel but not right.
Input JFETs are warm on both channels.
MOSFETS and all other components are cold.
All voltage measured relative to star ground. Voltages on the MOSFET pins starting with the pin nearest the small resistor.
Left channel (LED lit):
+V1, 25.0v
-V1, -25.v
Q1 pins 2.2v, 24.9v, 0.0v
Q2 pins 0.0v, 0.0v, 0.0v
Right channel (LED dark):
+V, 24.7v
-V, -24.8v
Q1 pins 0.0v, 24.6v, 0
Q2 pins -23.8v*, 0.0v, -24.7v
* first time reading it it climbed slowly to stable value, 2nd time dropped slowly to value.
Also poking about with probes (on Q1?) I shorted something and got a nice pop from speaker.
Just to verify, MOSFETS should be mounted with silver side in contact with heatsink?
Just to verify, "With DC voltmeter across the 0.47 source resistor, start by setting a bias reading of .5V (500mV)". The source resistor is the small resistor next to Q2 pins R12? BTW: I was getting 0v here.
Any suggestions would be appreciated!!
-Tom-
So I just did my first power up test of my F6 build and....
Nothing. But no magic smoke or bad odors.
On power up bulb tester lights up and goes to dark in 3 seconds and stays dark.
Led lights on left channel but not right.
Input JFETs are warm on both channels.
MOSFETS and all other components are cold.
All voltage measured relative to star ground. Voltages on the MOSFET pins starting with the pin nearest the small resistor.
Left channel (LED lit):
+V1, 25.0v
-V1, -25.v
Q1 pins 2.2v, 24.9v, 0.0v
Q2 pins 0.0v, 0.0v, 0.0v
Right channel (LED dark):
+V, 24.7v
-V, -24.8v
Q1 pins 0.0v, 24.6v, 0
Q2 pins -23.8v*, 0.0v, -24.7v
* first time reading it it climbed slowly to stable value, 2nd time dropped slowly to value.
Also poking about with probes (on Q1?) I shorted something and got a nice pop from speaker.
Just to verify, MOSFETS should be mounted with silver side in contact with heatsink?
Just to verify, "With DC voltmeter across the 0.47 source resistor, start by setting a bias reading of .5V (500mV)". The source resistor is the small resistor next to Q2 pins R12? BTW: I was getting 0v here.
Any suggestions would be appreciated!!
-Tom-
Hi Tom V,
you should measure the 0.5V at the 0.47Ohm 3W resistor.
Yes the silver side of the mosfet is facing the heat sinkt.
Pin 2 is electrically connected to the downside of the mosfet. You have to use a non conductive Thermal pad in between.
For the right channel with the led Problem.
I Think the led is soldered wrong way round.
A had the Same issue.
you should measure the 0.5V at the 0.47Ohm 3W resistor.
Yes the silver side of the mosfet is facing the heat sinkt.
Pin 2 is electrically connected to the downside of the mosfet. You have to use a non conductive Thermal pad in between.
For the right channel with the led Problem.
I Think the led is soldered wrong way round.
A had the Same issue.
I priced such a punch a few years ago. It was in 400.00 range. For poweramps, I've been using the Store's pre cut back panels. For my first (F5) build I built chassis. On it and preamps, I've been using Power Con connectors for same reason, takes a round hole, 7/8's inch if I recall.
Russellc
Nibblers, they work for metal and ceramic tile, or that's what I've used them for. Some drill a bunch of holes along the entire cut line, then file used to "straighten" them. Too much work and mess for me. I want to punch it out, or drill round hole. but, nibblers would work if you are stuck and that's the tool you have on hand.
Russellc
I have to correct myself here. I meant to say ADM audio console (not ADC).
It's a midwestern US brand from the 70's and 80's with good transformers and uses inductors in the equalizer circuits which is my favorite topology.
I'm not at the point of firing up my amp but close. I don't know if it will even work but if it does I am worried about hum -( I followed the guy with the hum problem and it looked like a pain)
A few questions:
In looking at the build guide I noticed that the wire from inputs seemed to be shielded which makes sense - but I noticed in some of the other pictures it was just two wires - I was thinking of just cutting up an old interconnect and using that.
What about wire gauge -- I'm wouldn't think it would matter too much. I think what I have laying around is 16 gauge or so and it doesn't seem like there is much current in there.
I've noticed the spiraling and saw a post where this helps with hum. Any particular pairs that are important.
Any tips on grounding and initial startup I have my lightbulb and I'm about set to start my power supply.
Would it make sense to test my board with a separate DC power supply or just confirm the voltage coming out of my power supply and go with that.
Sorry for so many questions I'm nervous about the next stage
A few questions:
In looking at the build guide I noticed that the wire from inputs seemed to be shielded which makes sense - but I noticed in some of the other pictures it was just two wires - I was thinking of just cutting up an old interconnect and using that.
What about wire gauge -- I'm wouldn't think it would matter too much. I think what I have laying around is 16 gauge or so and it doesn't seem like there is much current in there.
I've noticed the spiraling and saw a post where this helps with hum. Any particular pairs that are important.
Any tips on grounding and initial startup I have my lightbulb and I'm about set to start my power supply.
Would it make sense to test my board with a separate DC power supply or just confirm the voltage coming out of my power supply and go with that.
Sorry for so many questions I'm nervous about the next stage
Starting with the basics first:
One of the things that is really important to pay attention to is the difference between audio ground and chassis ground. Chassis ground is for safety and shielding. Audio ground is the reference point for your audio system, including the speakers.
The only direct connection to chassis ground is the ground lug on your AC mains inlet. The RCA input connectors, including the coax shield should not make direct contact with chassis ground. There may be one resistive contact (per channel in a dual-mono configuration) between audio ground and chassis ground. This resistive contact may be via an NTC thermistor, such as a CL-60, or by a 10 Ohm resistor in parallel with back-to-back power diodes. There are many examples of this in the various build guides.
I recommend making the audio ground to the negative speaker terminal directly from a ground terminal on the PSU board.
One of the things that is really important to pay attention to is the difference between audio ground and chassis ground. Chassis ground is for safety and shielding. Audio ground is the reference point for your audio system, including the speakers.
The only direct connection to chassis ground is the ground lug on your AC mains inlet. The RCA input connectors, including the coax shield should not make direct contact with chassis ground. There may be one resistive contact (per channel in a dual-mono configuration) between audio ground and chassis ground. This resistive contact may be via an NTC thermistor, such as a CL-60, or by a 10 Ohm resistor in parallel with back-to-back power diodes. There are many examples of this in the various build guides.
I recommend making the audio ground to the negative speaker terminal directly from a ground terminal on the PSU board.
tbrooke,
16ga wire for wiring is fine, except for signal input where most people prefer smaller wire.
Twisting wires together is helpful in noise control. Wires to twist together:
- AC live and neutral
- each transformer primary pairs
- each tranformer secondary pairs
- DC pairs from bridge rectifiers to power supply board
- V+ Gnd V- from power supply board to amplifier boards - twist the three wires together, do not braid.
- signal in pair
- speaker out pair
Here is a very informative guide by diyAudio member Bonsai:
http://hifisonix.com/wordpress/wp-content/uploads/2019/02/Ground-Loops.pdf
There is theory and practical information. The practical advice starts at page 54.
Page 1 of this Build Guide has useful and important information regarding the build and testing during initial startup.
Most definitely use a dim bulb tester on each initial startup until you are confident that you do not have any shorts. On power up the bulb will light up bright for a few seconds as the power supply capacitors charge. The bulb will then dim if there is no abnormal power demand or short circuit. If the bulb dims, you can then power down and power back up without the dim bulb tester attached. Page 1 of the build guide also has advice.
First test the power supply without the amplifier boards connected. Without the boards connected the output voltages will be a few voltage high.
After the power supply is tested OK, connect only one channel up and test. Follow the procedure outlined in the build guide page 1. Also be careful with the power supply after testing. The capacitors may take some minutes to discharge after power is disconnected. You can monitor that with your meter.
Connect and test the other channel.
It is best to have multiple meters so that you can monitor bias and DC offset at the same time. Use clip leads and connect the meters in place before powering up.
Again, read page 1 of this Build Guide.
16ga wire for wiring is fine, except for signal input where most people prefer smaller wire.
Twisting wires together is helpful in noise control. Wires to twist together:
- AC live and neutral
- each transformer primary pairs
- each tranformer secondary pairs
- DC pairs from bridge rectifiers to power supply board
- V+ Gnd V- from power supply board to amplifier boards - twist the three wires together, do not braid.
- signal in pair
- speaker out pair
Here is a very informative guide by diyAudio member Bonsai:
http://hifisonix.com/wordpress/wp-content/uploads/2019/02/Ground-Loops.pdf
There is theory and practical information. The practical advice starts at page 54.
Page 1 of this Build Guide has useful and important information regarding the build and testing during initial startup.
Most definitely use a dim bulb tester on each initial startup until you are confident that you do not have any shorts. On power up the bulb will light up bright for a few seconds as the power supply capacitors charge. The bulb will then dim if there is no abnormal power demand or short circuit. If the bulb dims, you can then power down and power back up without the dim bulb tester attached. Page 1 of the build guide also has advice.
First test the power supply without the amplifier boards connected. Without the boards connected the output voltages will be a few voltage high.
After the power supply is tested OK, connect only one channel up and test. Follow the procedure outlined in the build guide page 1. Also be careful with the power supply after testing. The capacitors may take some minutes to discharge after power is disconnected. You can monitor that with your meter.
Connect and test the other channel.
It is best to have multiple meters so that you can monitor bias and DC offset at the same time. Use clip leads and connect the meters in place before powering up.
Again, read page 1 of this Build Guide.
I braided mine along with PS ground. No issues as the amp is dead silent.
Twisting gives smaller loop area vs braiding. The difference may be small though. But I always try to do the best that I can so that I don't have to trouble shoot as much later.
3-wire power: twist or braid?
However, braiding is way better than having all the wires separate and loose.
3-wire power: twist or braid?
However, braiding is way better than having all the wires separate and loose.
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Mine are actually all twisted. Used the two terms interchangeably and should not have.