Thanks! I have posted there now too and seem to have traced the fault to sketchy ebay Jfets.
cheers
Well i am moving ahead slow and steady for the F5, just got over the power supply stuff. I am using a 2 X 18V, 600VA toroid. Funny thing is when I power it on, it humm's a bit and supply looks good...but when I switch it off and restart...it trips me power supply. Fortunately I have MCB's so I need to keep switching them on...am I missing something here??
Sent from my iPhone using Tapatalk Pro
Sent from my iPhone using Tapatalk Pro
What are the resistors on the output?? You don't want them for a Class-A amp.
The caps appear to be a short circuit when they are discharged, and with a 600VA transformer there is the possibility of drawing A LOT of current from the wall when you switch on. I suspect the circuit breaker is getting hot from the first power-up and the subsequent cycles are heating past it's trip point.
Use a CL-60 in series with the live to control the inrush.
The caps appear to be a short circuit when they are discharged, and with a 600VA transformer there is the possibility of drawing A LOT of current from the wall when you switch on. I suspect the circuit breaker is getting hot from the first power-up and the subsequent cycles are heating past it's trip point.
Use a CL-60 in series with the live to control the inrush.
F5 V3.0 build
Hi!
I just bought these diyAudio F5 boards to build the amp. But I couldn't find a specific build thread or BOM for these V3.0 boards. I even made the mistake of buying 2 completely forgetting 1 is for a pair. Now I am stuck in the middle. Please help! I am a complete newbie at this.
ericacaylar
Hi!
I just bought these diyAudio F5 boards to build the amp. But I couldn't find a specific build thread or BOM for these V3.0 boards. I even made the mistake of buying 2 completely forgetting 1 is for a pair. Now I am stuck in the middle. Please help! I am a complete newbie at this.
ericacaylar
all the info is on the bottom page of diy store where you bought the boards
class A not the best way to start building amps
I would suggest few chip amps first but its up to you
diyAudio F5 Build Guide
class A not the best way to start building amps
I would suggest few chip amps first but its up to you
diyAudio F5 Build Guide
power rating of the transformer is irrelevant, as long as its above the minimum recommended
Well... I am working on the new guide.
Here's an "in-progress" sneak peak. Might help you out.
Amplifier schematic. Print out and have in front of you at all times.
Right - PCB bag. Left - Kit of F5 parts.
The current F5 PCB from the diyAudio store. It has the inclusion of potentiometer P3, and is the third revision of this board, hence "F5v3"
The parts kit includes everting for the PCB except the input Jfets and the LED
One channel's parts
The Dale resistors have thier value printed on the side, the code is 3-digit + multiplier at values greater than 100ohm, and below 100ohm the "R" is the decimal.
So, from top to bottom you see
10K (100+2 zeros, 10000ohm)
1K (100+1 zero, 1000ohm)
100 ohm (100+0 zeros, 100ohm)
10.0 ohm (10R0, 10.0 ohm)
Lead spacing for all small resistors is .5inch (12.7mm)
Measure all resistors before inserting into the board!
Left side
Center
Right side
Big resistors installed. Blue are 0.47ohm 3W, Orange are 100ohm 3W. Values printed clearly on the side of each resistor.
Note that the parts kit does not include the LED or it's resistor, this is so you can choose that you prefer.
I used blue and a 15K resistor
Install the 5K pot and the ZTX450 on this side (Q6). Note the orientation of the transistor. The potentiometer value is almost the same code as the resistors - 502 is 50+2 zeros , 5000 ohms
Q5 is the ZTX550, note orientation, and use another 5K pot here.
The 200ohm pot mounts in the center, and the Jfets install as shown. The K170 is the N-channel, the J74 is the P-channel.
Mount the thermistors as shown and don't bend then yet.
Stuffed PCBs
[
Here's an "in-progress" sneak peak. Might help you out.
Amplifier schematic. Print out and have in front of you at all times.
Right - PCB bag. Left - Kit of F5 parts.
The current F5 PCB from the diyAudio store. It has the inclusion of potentiometer P3, and is the third revision of this board, hence "F5v3"
The parts kit includes everting for the PCB except the input Jfets and the LED
One channel's parts
The Dale resistors have thier value printed on the side, the code is 3-digit + multiplier at values greater than 100ohm, and below 100ohm the "R" is the decimal.
So, from top to bottom you see
10K (100+2 zeros, 10000ohm)
1K (100+1 zero, 1000ohm)
100 ohm (100+0 zeros, 100ohm)
10.0 ohm (10R0, 10.0 ohm)
Lead spacing for all small resistors is .5inch (12.7mm)
Measure all resistors before inserting into the board!
Left side
Center
Right side
Big resistors installed. Blue are 0.47ohm 3W, Orange are 100ohm 3W. Values printed clearly on the side of each resistor.
Note that the parts kit does not include the LED or it's resistor, this is so you can choose that you prefer.
I used blue and a 15K resistor
Install the 5K pot and the ZTX450 on this side (Q6). Note the orientation of the transistor. The potentiometer value is almost the same code as the resistors - 502 is 50+2 zeros , 5000 ohms
Q5 is the ZTX550, note orientation, and use another 5K pot here.
The 200ohm pot mounts in the center, and the Jfets install as shown. The K170 is the N-channel, the J74 is the P-channel.
Mount the thermistors as shown and don't bend then yet.
Stuffed PCBs
[
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Thank for your clear and well illustrated build guide. I just finished building the amp boards, I used a build guide from 2012. In this build I noticed that the pots were mounted the other way around as well as the jFets. Am I missing something? If so I will have to desolder every thing. Thank for your reply.
That should be a x-rated suppression capacitor. Perhaps one of these:
ERP610W332MEJ0 KEMET | Mouser Canada
ERP610W332MEJ0 KEMET | Mouser Canada
Interesting, why is class A not good to start?
I've built a chip amp and a tripath, but those were on guides where I had a diagram of where everything went, rather than a schematic.
Thanks