Yup. I'm building an F5! Here are my questions

[nerdorama]

Originally Posted by bear

They should not sound harsh, period.

A lot though depends on the rest of your system, and what it is.
The term is GIGO (garbage in, garbage out).

Check and adjust ur bias point. That effects the overall sound.
Also the power supply will have a significant effect on what you hear. Urs looks basic, things like the bridges and the way you do the filtering will effect what comes out the other end. Even the brand of power resistors used on the board seem to have an effect.


_-_-bear

Thanks for the comments. My power supply is per Nelson's schematic and similar to what many others in the threads have used. The parts are all respected name brands from Mouser and Digikey. As for bridges, I used standard units as Nelson suggests rather than the fancy bridges that some others have pursued. My experience is that almost all new electronics have a short break-in although I know some don't believe in that. The amp is sounding quite smooth now but not as good as my tube amp.

Best,
John

[6L6]

Specific to PSU board, there is one from Chipamp.com (not the one for the gainclone, but made for the Aleph) that I am waiting on receiving. (they are backordered, with a new shipment on the way.) Once I have it in my hands I will know if it's an awesome choice or not, and will be happy to suggest suitable parts that fit the board.

If you use the Peter Daniel board you have a ton of choices with caps, as it will fit just about anything, but only 4 total.

Would still like to know how big your heatsinks are.

[ouimetnick]

Originally Posted by 6L6

Specific to PSU board, there is one from Chipamp.com (not the one for the gainclone, but made for the Aleph) that I am waiting on receiving. (they are backordered, with a new shipment on the way.) Once I have it in my hands I will know if it's an awesome choice or not, and will be happy to suggest suitable parts that fit the board.

If you use the Peter Daniel board you have a ton of choices with caps, as it will fit just about anything, but only 4 total.

Would still like to know how big your heatsinks are.

I'll hopefully get around to measuring the heatsinks tomorrow. I'm sure they are big enough, but I gather that the can amp still get hot as hell even though there are only two transistors mounted to it, due to high bias, and it being a class A amp.

[6L6]

From the manual --

Heat Sinking
At 1.3 amps per channel, you will see idle heat dissipation of 62 watts. To keep the temperature rise of the heat sink to 20 deg C. above the ambient temperature, you will want a heat sink rated at about .6 deg C./watt for each transistor. An example of this would be a chunk of finned aluminum, with a series of 2” fins attached to an 8” by 6” base. You will need two per channel.

----

So that means about 8" x 12" per channel. If they are notably smaller than this you will probably need a fan.

[6L6]

Originally Posted by IZHAKKATZ

Hi All,

Greetings!

I'm also a newbie about to purchase and build an F5
For the PS when using in Europe with220V mains, should C9 be .0033uf\250V ?

That will work, but higher voltage is better

Can you recomend type and brands of resistors for the PS?

Panasonic, Dale, Xicon. It's not that critical, metal film 3W dissipation.

I'll be using the F5 with a B1 pre. Can anyone please recomend type and brands of caps at the input of the amp to avoid DC going to speakers?

The big 10uf film caps in the B1 do that job. The F5 will not need any.

[IZHAKKATZ]

thank you 6L6

The pre will be the Hypnitze DCB1 (purchased a black white red kit )
so 10uf will do? What brands would you recommend?

Thanks
IK

[6L6]

DCB1 has no caps, and does not need them. Normal B1 has caps. If your Hypnotize is set up properly you won't need to worry about it.

[turboyam]

Originally Posted by ouimetnick

Hi everyone!
I'm really excited to get started on building an F5. i've heard nothing but great things about the amp, so I bought some boards from the DiyAudio store, and here we go.

P-F5-2V20 - Pair of F-5 boards (Makes 2 channels; Rev 2.0) - Boards

Anyways, the boards are V2.0 dated 2010-10-23 caviler layout

So I have the BOM

Attached is the BOM, and I have several questions. I plan on just throwing all the board components into a Mouser project, and ordering. They don't seem to have all the transistors, and I will discuss them later.

Just one questions for resistors... well two actually. I know K means 1000, so 100K=100,000

But what does R mean? Like 10R, 100R, 0.47R 150R, etc?

Also, I'm going to use metal film resistors? Is that okay?

As for the pots, P1, and P2 are both 5K. Can someone point me to the mouser part number (or digikey) for the pot? I can find a lot of 5K pots, but I need one that fits in the holes. One with the right spacing. :-)

As for the NTC thermistor, its 4.7K.. whats the wattage? Can someone point me a link or something?

Also, what about LED1? What should I use for that? Again, a link would help me.

Now onto transistors.

Q1: 2SK170
Q2 2SJ74

Aren't these transistors difficult to find? I heard one of them was discontinued with no replacement.. I have a source for them, but do they need to be matched? If they do, what is it for? Low DC offset?

As for Q3 and Q4, what website has them?

What brand should be used for them? Any matching needed for these? I know they are the outputs.

As for Q5 and Q6, Mouser has them.. nuff said. But do they need to be matched?

Now with all that done, heres the other set of questions.
__________________________________________________ _________________

Transformer should be a 18-0-18. What VA would work? Can I simply wire up the power supply like in a Hafler DH-200?

I would simplify if though. I would get rid of the thermal breakers, as they would be on the PCB, and get rid of the high temp lamp.

The center tap of the transformer is connected to the ground bus between the two filter capacitors. For filter caps, would two 22,000µF work? Also, having an B+ and B- fuse for each channel. Thats my plan for the wiring. The ground of the RCA jacks is grounded to the bus bar, and so is the negative output for the speakers. Fuses will be put inline with the positive speaker output.

As for a chassis, I'm simply reusing an old Yamaha receiver.. Don't worry, the heatsinks are huge.
__________________________________________________ _________________

Sorry for some of the stupid questions, but I'm not an electronics genius yet. I'm only 16, and money is an issue, so thats why I'm not going to buy fancy resistors and stuff. Just regular components.


Thanks so much for the help!
-Nick

I find it fantastic that a 16 year old wants to build such a high quality amp!
boys your age are usually happy listening to BPC stuff, compressed dynamics and bandwidth, cumming thru a mp-3 or whatever crap like it!.
Not to forget those 1234 watts channel car systems ahhaahahah yeah right

[turboyam]

so...... keep-up great work Ouimetnick!!!.

[barry_e]

Ouimetnick you may wish to act quickly to order from techdiy. In an email of a day ago the propreitor said has a few F5 kits left- he said when they are gone they are gone.

I would have bought them but I have an older board set from a Peter Daniel group buy of years ago and not all of the parts are the same.

For transistor kit . . .

Please see: F5 amp transistor kit

Barry