F5 power amplifier

[Hikari1]

Hello everyone, some time ago I finished the Pearl 2, B1 and F5 chain, I like it a lot. I also implanted Mundorf audiophile condensers in B1. It was worth it! don't believe anyone who says something different.
But I want the helicopter in "The Wall" by Pink Floyd to land IN my room and not outside.
When I think of driving my JBL Ti6K via bi-amping. Before I start getting material, the community would like to ask if F5 and F5Tv2 can play correctly in phases?
I wanted to build the F5 Turbo anyway, it would be the right opportunity.

F5 turbo has more gain due to less feedback. You would need some way to adjust levels between f5 and f5t.

Also, having built both, I feel that f5T sounds different from the regular f5. Less lively. Smoother and not as exciting. Could be better or could be worse depending on your listening preferences and other equipment.

F5 with buffers (like b1) is in my opinion unexciting and boring. Too smooth, no impact, you begin to listen to the system instead of the music. I have tried b1 and b1 rev2. Both of which didn’t have enough gain but both were extremely detailed and precise.. B1 rev2 was particularly too much of this for me with the f5.

 

[dezibaby]

Thank you for quick answers!
actually it was not clear to me whether the playback of F5 and F5Turbe would remain in phase, because in the turbo version there is an additional transistor in the chain and that cannot cause this.
Yes, it is also about reinforcement that I only want to run the upper and middle wing with F5. Turbo for the low frequencies. If the turbo had twice the power, it seemed like 1.3 mall louder, I think I can live with that. the most important phase accuracy.
When the input signal gets too small, I thought something crazy: After the B1 still Burning Amplifier Gain Stage Board
(Burning Amplifier Gain Stage for BA-1 & BA-2 – diyAudio Store)
in front of power amplifiers.

 

[Hikari1]

If the regular f5 is loud enough for you, especially with only the b1 as buffer I would not recommend the f5T. It is possible to build an f5T with dual pair of mosfets, regular f5 24v rails and regular f5 feedback. Extra pair of mosfets allows you to bias higher which always sounds better. Bias is the key here, the more bias you can get the better it will sound.

There is no point in putting a b1 in front of a burning amp gain stage. The gain stage already is buffering the output and has a high input impedance. Just put volume pot in front of gain stage.

Honestly, you need to try the Korg B1. It’s cheap and easy and sounds better than 4 or 5 of the diy preamps I have tried. It is a perfect partner for the F5. Lots of gain and increases the 3D nature of the f5. If you think your B1/f5 combo images well now you would be shocked by the korg B1.

 

[Chiptech]

What is this?

Appropriate any help in clarifying the purpose of what the red arrow is pointing to. And any direction on more info on it.

Thanks

 

[ItsAllInMyHead]

Looks like a ferrite choke. Can help with some HF noise from EMI / RMI that can ride in on the mains. (I think).

 

[Ben Mah]

Ferrite bead for EMI filtering?

Slow on the draw.

 

[flamethrower1]

Noise filter, I have only two amp builds behind me and have not used one, no hum, actually black between songs, well beside the noise of the needle on the album occasion.
Pay attention to how you route your wires and you should be good.
Find a better terminal block though

 

[Chiptech]

So I can ignore it. Thanks

I've looked for terminal blocks, haven't found much.

 

[flamethrower1]

something like this
McMaster-Carr

 

[Chiptech]

Sorry but the link doesn't get me to the product. Can you give me the product code?

Thanks

 

[tjalfe79]

I forgot to order insulators when i last bought from diyaudistore.
Will the keratherm 86/37 works instead or should i get something different.

Specs are.

Thermal resistance R 0.28 K/W
Thermal impedance 125 Cmm²/W
Thermal conductivity 1.8 W/mK

 

[jackinnj]

I still have F5 "kits of components" available -- including JFET 2SJ74/2SK170, MOSFETs IRFP240/9240, Zetex devices, thermistor and resistors -- $27 per channel, $54 for two. PM if interested.

 

[cviller]

This made me look in my storage and I found that I have a few F5 boards available if anyone is interested. It is the one I called F5c V2.2, which is pretty much the F5 turbo without diodes on the output.

Here is a thread about them:
F5c (cascode) cviller boards 40 V rails build

PM me if interested.

 

[Nelson Pass]

The F5 still has considerable life left in it. I have a version which we will make
available after the DIY VFET amplifiers are put to bed.

 

[2 picoDumbs]

Awesome

I have some Toshiba device reserved for an F5 build.

I will be curious to learn more.

 

[gary s]

Oh no, here he goes teasing us again - will it ever stop.

 

[mbrennwa]

Did I just read F5 and VFET in the same sentence?

 

[2 picoDumbs]

I don't think he was referring to using vfets on an F5 build, just that chronologically it will be released after the vfet amp.

 

[noelectrix]

 

[2 picoDumbs]

The F5 still has considerable life left in it. I have a version which we will make
available after the DIY VFET amplifiers are put to bed.

Any tips based on your plans you would give for Toshiba output mosfets.

Thinking of using 50mOhms source resistance or none at all on output.

With the biasing circuit using thermistors should any changes be made?

I am not using the current limiting circuitry.

Jfets have idss of 7mA