F6 Illustrated Build Guide

A very nice and tidy looking build! I hope you will have many hours listening to music through this amplifier.

Small observation: I can't see a CL60 (or similar arrangement) for lifting signal ground. Not absolutely necessary, but beneficial for reducing hum.

Also, if/when you want to do an improvement, add the green led mod to the amplifier. It won't affect the sound but it will insulate the amplifier from changes in the ambient temperature, and when you put the lid on.
 
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@RThierry - Lovely looking build.

In addition to strongbow60's great observations / questions below, here are a few other thoughts.
Small observation: I can't see a CL60 (or similar arrangement) for lifting signal ground. Not absolutely necessary, but beneficial for reducing hum.
Agreed. Some sort of ground lift is a great consideration, if you don't have one in place.

Also, if/when you want to do an improvement, add the green led mod to the amplifier. It won't affect the sound but it will insulate the amplifier from changes in the ambient temperature, and when you put the lid on.
It's a great mod, but that's not exactly what it does. :) In basic terms, it helps to stabilize the circuit more quickly as key components warm and/or cool. It's particularly beneficial if you're one of those people that goes bonkers with a little bit of bias drift and/or offset shift; and/or if you think your amp sounds better after an hour or so of warm up (and you turn your amp on and off 'a lot').

If you're interested in how it works or why, there's a dedicated thread. It is correct that it should not affect the sound. Hey wait, but if it doesn't affect the sound... then why do it? Great question. :D I'd hold off for now were I in your shoes. If/when you may want to fiddle with new output devices or have another reason to take your boards off the sinks, that might be a great time. In general, once my amps are working, I leave them in peace, but even I have the tendency to not leave well enough alone.

I also didn't see any inrush current limiting mechanism or 'safety' caps in the build. Is there something in place that I did not see? If not, what value fuses/fuse types are you using? Is it a 300VA or 400VA transformer; I can't quite see, but from the size, that's my guess. Neither the caps nor the inrush limiter are strictly necessary, but it's just my curiosity.

Enjoy the tunes!
 
A couple of things:

Those quick connect type connectors are notorious for not being able to take much current. Electricians tend to frown on them.

There is no soft start it looks like in your build. The transformer goes straight to the mains. Typically you would have an arrangement of three cl-60's or a soft start board. I did run my F6 for a few days without it when I first built it but I did notice more startup hum from the transformer. Look at 6l6's pic of it in the first post of the build guide. I believe there is some discussion within the last few pages of this thread about it as well.

The build looks great otherwise!
 
I hope it doesn't seem like I'm calling you out or specifically disagreeing, but I have some questions.
A couple of things:

Those quick connect type connectors are notorious for not being able to take much current.
They are? The orange ones? They're usually rated components. If they're not able to handle the rated current/power, then the user has likely chosen the wrong part, IMO.
Electricians tend to frown on them.
They do? I've see similar parts in many industrial applications. Has it been your experience that electricians looking after your home and/or business have advised against them? We're just working from different anecdotal info.
There is no soft start it looks like in your build. The transformer goes straight to the mains. Typically you would have an arrangement of three cl-60's
Three? In general, in a 'standard First Watt power supply' if one or two are used, it depends on the mains voltage and transformer primary arrangement. It may be helpful if you point to a schematic.

Are you perhaps adding the two which might be typical with 120VAC mains voltage using a dual primary transformer wired in parallel along with another similar device used as a ground lift? Total - 3.
 
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They do? I've see similar parts in many industrial applications. Has it been your experience that electricians looking after your home and/or business have advised against them? We're just working from different anecdotal info.

Three? In general, in a 'standard First Watt power supply' if one or two are used, it depends on the mains voltage and transformer primary arrangement. It may be helpful if you point to a schematic.

Are you perhaps adding the two which might be typical with 120VAC mains voltage using a dual primary transformer wired in parallel along with another similar device used as a ground lift? Total - 3.

Not a problem.

Connectors:
I like those connectors on things like LED lights and lightweight applications like that at the end of a run. However, yes, they are frowned upon for being used in a junction box to tie a couple circuits together etc. Wirenuts are the safer option in house and commercial wiring. It is like backstabbing an outlet vs using the screw terminals on the side.


CL-60's:
In 6l6's amp build, he has one for the hot one for the neutral and one for ground. Of coarse whatever firstwatt uses is good as well. I will try to remember to look for the schematic later when I get home.
 
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Not a problem.

Thanks!
Connectors:
I like those connectors on things like LED lights and lightweight applications like that at the end of a run. However, yes, they are frowned upon for being used in a junction box to tie a couple circuits together etc. Wirenuts are the safer option in house and commercial wiring. It is like backstabbing an outlet vs using the screw terminals on the side.

Makes perfect sense. Appreciate your POV for that application.
CL-60's:
In 6l6's amp build, he has one for the hot one for the neutral and one for ground. Of coarse whatever firstwatt uses is good as well. I will try to remember to look for the schematic later when I get home.
No need. Jim's PSU is based off the standard First Watt PSU. My guess is that you're adding the two thermistors used in one specific configuration to limit the inrush current (see 120 VAC reference below with the thermistors circled in red) to the device used to lift the ground (circled in green). Two are for 'soft start', and the other is for a ground lift. Thanks for explaining your POV. All clear.
 

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@RThierry - Lovely looking build.

In addition to strongbow60's great observations / questions below, here are a few other thoughts.

Agreed. Some sort of ground lift is a great consideration, if you don't have one in place.


It's a great mod, but that's not exactly what it does. :) In basic terms, it helps to stabilize the circuit more quickly as key components warm and/or cool. It's particularly beneficial if you're one of those people that goes bonkers with a little bit of bias drift and/or offset shift; and/or if you think your amp sounds better after an hour or so of warm up (and you turn your amp on and off 'a lot').

If you're interested in how it works or why, there's a dedicated thread. It is correct that it should not affect the sound. Hey wait, but if it doesn't affect the sound... then why do it? Great question. :D I'd hold off for now were I in your shoes. If/when you may want to fiddle with new output devices or have another reason to take your boards off the sinks, that might be a great time. In general, once my amps are working, I leave them in peace, but even I have the tendency to not leave well enough alone.

I also didn't see any inrush current limiting mechanism or 'safety' caps in the build. Is there something in place that I did not see? If not, what value fuses/fuse types are you using? Is it a 300VA or 400VA transformer; I can't quite see, but from the size, that's my guess. Neither the caps nor the inrush limiter are strictly necessary, but it's just my curiosity.

Enjoy the tunes!
Thanks for the as-built review and recommendations. I do not have any in-rush protection or cl60 installed. I’ll do some power supply build reviews to see how to add. The fuses are 3 amp that came with the switch. I’ve got the bias at 0.5 and the offsets near zero. No hum at all so far. The transformer is AnTek 300 VA, AS-3218.

This is my third amp build after the amp camp and the Nutube pre-amp So my knowledge if power supplies and amps is limited.

The Wago connector is used to connect the mains to the transformer. They feel solid. See picture of the connector and rating.
 

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The Wagos are heavily used for mains wiring in junction boxes etc. in Germany. It's the standard way of connecting wiring nowadays.
When I was a kid, mostly screw terminals (terminal blocks / Euroblocks) where used in this application, but these tended to suffer from corrosion long-term (years to decades), and you could safely use them with multi-stranded wire (as opposed to solid-core) only when you put ferrules on the stripped ends of the wires before fastening them. The Wagos work for both solid-core and multi-strand.
We frown upon wirenuts here ;)

Best regards, Claas
 
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@ItsAllInMyHead About the green gas from Xabiste, sorry the green led mod... Actually, from my experience it works as I described it - as well as it does in your description. This is the same effect in action.
The led's have a negative temperature coefficient and when the amplifier is turned on from cold this will mean a higher current through the mosfets at the start. This will create a faster warm up and stabilization period lending to what you mention. A side effect is if you take the cover off this means better air flow through the chassi and a higher current. I found that out by chance, first setting the current with the lid off and - still connected leads to the multimeter - put the lid back on.
Right now it is 30 C outdoors and 28 C indoors, while sitting on the balcony I am still able to enjoy my F6 playing in the living room :flame:
 
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I wish not to side track this thread with connector chat, but WAGO 221 connectors are perfectly acceptable for electrical use as Claas mentioned. DIY audio amplifier power requirements do not come close to stressing them.
https://www.wago.com/us/discover-wire-and-splicing-connectors/221
You are probably right. I have seen too many of them with burn marks on them that I don't trust them all that much. Maybe it is due to an installer error. I do handyman work so I run across them every once in a while.

Wagos or not, the F6 is an excellent amp.
 
@ItsAllInMyHead About the green gas from Xabiste, sorry the green led mod... Actually, from my experience it works as I described it - as well as it does in your description. This is the same effect in action.
The led's have a negative temperature coefficient and when the amplifier is turned on from cold this will mean a higher current through the mosfets at the start. This will create a faster warm up and stabilization period lending to what you mention. A side effect is if you take the cover off this means better air flow through the chassi and a higher current. I found that out by chance, first setting the current with the lid off and - still connected leads to the multimeter - put the lid back on.
Right now it is 30 C outdoors and 28 C indoors, while sitting on the balcony I am still able to enjoy my F6 playing in the living room :flame:
I think we are saying the same thing, but using different words, perhaps. I was confused by your original words; "it will insulate the amplifier from changes in the ambient temperature, and when you put the lid on."

I took insulated too far and interchanged it in my head with "isolated". I now understand your meaning.

Thank you for taking the time to clarify.

Cheers!
 
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