hello all,
sorry for my newbie's question it's my first build, i have bought an essential kit F5M a 4 month ago, (completion kit was not available at this momment) i was having no time to work on it. now it's holliday for me, i want to order all the parts and build it, when i write designation of some article on digikey some are not available or replaced:
RES 270 OHM 5% 2W
RES 22 OHM 2 W
RES 0.47 OHM 2W
are replaced by 3W have it an impact on the rest of the construction?
insulator BER1340-ND is not available, what can use to replace?
since the begining does there is improvement of the initial design i have to make?
what cable do you use advise for internal cabling?
there is some other parts to order wich are not on the list?
thanks in advance
sorry for my newbie's question it's my first build, i have bought an essential kit F5M a 4 month ago, (completion kit was not available at this momment) i was having no time to work on it. now it's holliday for me, i want to order all the parts and build it, when i write designation of some article on digikey some are not available or replaced:
RES 270 OHM 5% 2W
RES 22 OHM 2 W
RES 0.47 OHM 2W
are replaced by 3W have it an impact on the rest of the construction?
insulator BER1340-ND is not available, what can use to replace?
since the begining does there is improvement of the initial design i have to make?
what cable do you use advise for internal cabling?
there is some other parts to order wich are not on the list?
thanks in advance
Fellow noob here Pierrick59, just completed my F5M a couple of weeks ago. The 3 watt resistors were what I used also with no issues. For the insulators I used the store Keratherm ones, only $18. For wiring I had a good supply of Ancor 16 gauge tinned marine wire, 6L6 prefers the Remington wire available on Amazon in various gauges and colors. Also Toys4Boyz has an excellent thread "A Beginners DIY Journey" that has valuable advice on tools, etc.
What chassis were you planning on?
What chassis were you planning on?
Thank you SimpleJim,
for the insulator do you have a link to make no mistake ? i prefer on digikey because if i order 50$ i don't pay shipping
does i must use trimmer to finish?
i plan to buy this chassis: https://modushop.biz/site/index.php?route=product/product&path=210_272&product_id=453
and this transformer: https://sklep.toroidy.pl/en_US/p/TTSA0300-Transformer-AUDIO-TSA300VA-voltage-to-50V-/317
for the insulator do you have a link to make no mistake ? i prefer on digikey because if i order 50$ i don't pay shipping
does i must use trimmer to finish?
i plan to buy this chassis: https://modushop.biz/site/index.php?route=product/product&path=210_272&product_id=453
and this transformer: https://sklep.toroidy.pl/en_US/p/TTSA0300-Transformer-AUDIO-TSA300VA-voltage-to-50V-/317
The insulator solution I mentioned on the previous page should do the trick if you do not feel like making a 2nd DIYaudio order:
https://www.diyaudio.com/community/threads/f5m-kit.408290/post-7747839
I am not sure there is much to improve as the amp has very little to it already. I say build it stock, then experiment. I believe TungstenAudio has built the F5m. He likes to tweak things so maybe you can find some ideas there. regardless, build it stock first then play around.
https://www.diyaudio.com/community/threads/f5m-kit.408290/post-7747839
I am not sure there is much to improve as the amp has very little to it already. I say build it stock, then experiment. I believe TungstenAudio has built the F5m. He likes to tweak things so maybe you can find some ideas there. regardless, build it stock first then play around.
@Pierrick59 : The ceramic pads Mikeodrig27 mentioned is also available at Digikey: https://www.digikey.ca/en/products/detail/boyd-laconia-llc/4180G/1625664
Don't forget that with hard pads you need to use thermal paste.
You will need trimmers to adjust and set the bias. Be sure to order ones with the correct footprint.
3W power resistors are fine. Just check that their lengths are not longer than the lead spacings on the PCB.
Don't forget that with hard pads you need to use thermal paste.
You will need trimmers to adjust and set the bias. Be sure to order ones with the correct footprint.
3W power resistors are fine. Just check that their lengths are not longer than the lead spacings on the PCB.
Thanks all
the trimer rest in the construction?
i see there is no volume control... i suppose i have to control volume with the source?
can send me a link😉, it's really the first time that i make that...
the trimer rest in the construction?
i see there is no volume control... i suppose i have to control volume with the source?
Nice chassis, I used the Mini-dissapante 4u as I wanted to mount the transformer vertically and it has larger heat sinks. I would highly recommend getting the internal baseplate and pre cut back panel substitute in 3 mm aluminum from Modushop. Very difficult to cut holes in 1 mm steel backplate I understand. Also I would recommend getting the Modushop predrilled heat sinks, you will save money and frustration by not having to buy a tap, tap wrench and drill bits. And yes you will need a volume control, either by preamplifier or a variable output DAC.
The F5m is a power amplifier only. The volume control is in the preamplifier or other source.
There should be enough space to do this if needed:
There are creative ways to add volume control but as Rayma says, it was originally intended to be used as an amp.
You can do a passive volume control if you like. For that something as simple as a stepped attenuator with a line in and line out would work. A step up would be a B1 buffer which will help sources that are not up to the task of driving an amp. The buffer does not add voltage gain but adds current gain. This means that it does not add volume over simply having a stepped attenuator. The next step up would be if you needed more voltage gain for speakers that are not so sensitive. Maybe a B1 Korg or a BA3. Lots of cool stuff. But simply having a F5m is a great start! 🙂
Attachments
https://www.digikey.com/en/products/detail/bourns-inc/3296Y-1-102LF/1088084 Try this if you would like a multiturn version. Check the Datasheet for exact dimensions and specs. It is linked on the page. There are several configurations available, including straight pin, triangle pin arrangement, top adjuster, side adjuster, etc. choose one that will fit your board.
Multiturn recommended as above, the single turn in the kit makes it difficult to make precise settings.
What are you currently using right now? Where are you currently controlling your volume?
Perhaps you can list your whole chain from source->amplification->speakers. Let's make sure what pieces you need to build.
at the momment i have not so much, i start to improve my chain
a cd reader philips
a computer
a amplifier NAD c356 BEE
1 DIY pair with Mark audio MAOP 10.2
1 DIY pair with sb acoustics SB20FRPC30-8
i don't see it on the board... the trimmer rest in the building?
trimmer in the basis kit are not enough? (3386P-1-102LF)
does there is a tutorial step by step for the building?
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How hot are the thermistors gonna run in the power supply? Should I leave them on their big long legs (distance!) to try to avoid baking the capacitor bank?
I see in the amp PDF to choose a line fuse smaller than the current rating on the thermistor, which looks like 5A when I look up the part. So is 3A the right way to go? I don't have a feel for what the inrush current is going to look like.
Could someone explain why a thermistor in the path to ground makes sense? I see the comment in the PDF that it's useful for avoiding ground loops. I thought one wanted their path to ground to be low impedance.
Thanks for the enlightenment!
I see in the amp PDF to choose a line fuse smaller than the current rating on the thermistor, which looks like 5A when I look up the part. So is 3A the right way to go? I don't have a feel for what the inrush current is going to look like.
Could someone explain why a thermistor in the path to ground makes sense? I see the comment in the PDF that it's useful for avoiding ground loops. I thought one wanted their path to ground to be low impedance.
Thanks for the enlightenment!
The audio ground connection to the chassis is not necessary for proper amplifier circuit operation.
No current normally flows in the chassis, which causes it to serve as a shield, since the chassis is
connected to audio ground at only one point, in this case through the NTC thermistor.
However, the chassis is needed for safety. If an electrical short to the chassis happens, fault current
will flow through the chassis to the IEC safety ground, which will cause the AC line fuse to blow.
The NTC thermistor is normally a high value of resistance at room temperature. This helps reduce noise
in the audio circuit. Ground loops can happen due to a noisy AC line safety ground.
Should fault current flow into the chassis through the NTC thermistor, it will heat up and have a low resistance,
which allows enough fault current to flow to blow the AC line fuse.
No current normally flows in the chassis, which causes it to serve as a shield, since the chassis is
connected to audio ground at only one point, in this case through the NTC thermistor.
However, the chassis is needed for safety. If an electrical short to the chassis happens, fault current
will flow through the chassis to the IEC safety ground, which will cause the AC line fuse to blow.
The NTC thermistor is normally a high value of resistance at room temperature. This helps reduce noise
in the audio circuit. Ground loops can happen due to a noisy AC line safety ground.
Should fault current flow into the chassis through the NTC thermistor, it will heat up and have a low resistance,
which allows enough fault current to flow to blow the AC line fuse.
I like to try other output mosfets in this kit. Is it ok if the mosfets are not matched? Like FQA36P15 / FQA28N15 or somebody have better pair to suggest what to try in this kit?
I'm only running a little over 1a of bias and the thermistors are pretty hot, you don't want to touch them for more than a second. They don't seem to be making the caps hotter, but I've only got half a chassis and a big fan, so.
Regarding other Mosfet pairs, yes I have found a match which sounds wonderful.
I paired the FQA28N15 with IXTQ26P20P. Details of the build are in the other F5m thread.
Post in thread 'Pass F5m'
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7618191
Using the standard F5 boards, I was able to ‘tune’ the gate stopper resistors to better match the alternate Mosfets. One could try these with the special F5m kit boards and no gate stoppers, or possibly find a clever way to add gate stoppers.
I paired the FQA28N15 with IXTQ26P20P. Details of the build are in the other F5m thread.
Post in thread 'Pass F5m'
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7618191
Using the standard F5 boards, I was able to ‘tune’ the gate stopper resistors to better match the alternate Mosfets. One could try these with the special F5m kit boards and no gate stoppers, or possibly find a clever way to add gate stoppers.