F5 Turbo V3 monoblocks 32v dc rails psu

[motorica]

Hi

I planned to build 2 F5 turbo v2 monoblocks and i just finished collecting the parts including 2 x 5U enclosures.

Toroids are 2 x 24va 600kva total capacitance 176,000 per channel.

Now i'm thinking why not to build the v3 version ?
I need to buy extra set of diyaudio pcbs but i need to know if it's possible with 24vac secondaries (32vdc rails).
If so can i expect 100w @ 8 ohm ?

Thanks
David

 

[Zen Mod]

at least 45Vdc rails

for 100W/8R you need 80Vpp at output

 

[AudioSan]

you don't realy need 2 of those chassis and transformers for v2. a stereo v2 in one chassis with one 600VA transformer will do the job.
transformer sec voltage for v3 should be 2x 35-40Vac. 600VA or higher pr ch.

 

[2 picoDumbs]

If you want 100W with your existing transformer secondaries a balanced/bridged F5 or F5X will certainly give you that.
Probably biased for 50W class A then AB for the rest of the way to over 100W.
This may not be what you want to do I'm just throwing out ideas you can work with

 

[motorica]

Is it worth the effort of using two 24vac toroids īn single chassis , turbo v2 build?

Doesn't ordinary f5 turbo v2 specs are 50w class a @8ohm and 100w class ab @4ohm?

I want to maximize the build with the parts i have already bought.

Thanks !
David

 

[Zen Mod]

you asked for 100W/8R

what is exactly next question ?

 

[AudioSan]

Is it worth the effort of using two 24vac toroids īn single chassis , turbo v2 build?

Doesn't ordinary f5 turbo v2 specs are 50w class a @8ohm and 100w class ab @4ohm?

I want to maximize the build with the parts i have already bought.

Thanks !
David

you can use 1 or 2. or you can build monoblocks with 4 outputpairs and 4A bias for higher class A power in lower loads. there is a lot of options.

 

[motorica]

I'm a bit confused so i will rephrase my question.

2 options for the build, i preffer monoblocks

1. 600kva 2x24v secondaries transformer and 4 pairs of output devices (one set of diyaudio boards)

2. Same transformers 600kva 2x24v but with 8 pairs of output devices (2 sets of diyaudio boards)

The psu capcitors are 63v letting me in the future to replace the transformers to 35V secondaries, but for now i need to know if there is any added value if i choose option 1.

Thanks!
David

 

[2 picoDumbs]

Is option (1) mono vs option (2) stereo?
What do you mean by 2 sets vs 1 set of diyaudio boards?

 

[motorica]

both options are mono chassis.
1 set of diyaudio boards supports 4 pairs of output devices for 2 monoblocks.
If i want 8 pairs if output devices, 2 sets of boards are needed.

David

 

[AndrewT]

Krell use a 1kVA 37-0, 37-0 transformer for their 100W into 8ohms KSA100.

You cannot get 100W into 8ohms from one channel on a 24+24Vac transformer.

Later I see F5x and 100W.

The F5x is rated as 50W into 8ohms. It uses double the number of output devices for double the power of a standard F5.

If one increased an F5x to 8devices, one gets a version of F5Tt v3 and with considered design could get to 100W into 8ohms.

But judging by the expertise you have displayed, you don't have any hope of achieving a successful and reliable build.
You have a lot of learning to do.
Start with lower targets until you have the necessary expertise.

 

[motorica]

I already built amb b22 headphones amplifier
Several tube preamplifier, the last one with lcduino as volume controller.
Several class d amplifiers and gainclones.

I have no fear what so ever building the v3 versions.
I just asked a simple question if there is any power increase doubling thw output devices from 4 to 8 pairs eith 24v secondaries given the appropriate cooling capacity. standard v2 is capable of 50w~.

Thanks
David

 

[AndrewT]

I already built amb b22 headphones amplifier
Several tube preamplifier, the last one with lcduino as volume controller.
Several class d amplifiers and gainclones.

I have no fear what so ever building the v3 versions.
I just asked a simple question if there is any power increase doubling thw output devices from 4 to 8 pairs eith 24v secondaries given the appropriate cooling capacity. standard v2 is capable of 50w~.

Thanks
David

this reply shows your lack of expertise.

I won't worry about the outcomes. Do your own thing.

 

[motorica]

I'm here to learn not to be judged of my knowledge.

 

[MASantos]

... is any power increase doubling thw output devices from 4 to 8 pairs eith 24v secondaries given the appropriate cooling capacity. standard v2 is capable of 50w~.

Thanks
David

The power capability is directly related to the voltage and current capabilities of the amplifier, not to the number of output devices.

Increasing the number of output devices allows you to increse the voltage and current of the amp while maintaining safe operating conditions.

I also changes the performance of the amplifier into different loads.

 

[WalterW]

I already built amb b22 headphones amplifier
Several tube preamplifier, the last one with lcduino as volume controller.
Several class d amplifiers and gainclones.

I have no fear what so ever building the v3 versions.
I just asked a simple question if there is any power increase doubling thw output devices from 4 to 8 pairs eith 24v secondaries given the appropriate cooling capacity. standard v2 is capable of 50w~.

Thanks
David

Hi David,

I built a v3 also at 32 V, there is no power increase with more outputs. Only more power when you increase the PSU voltage.
With 8 outputs you can spread the heat better and that is a great advantage!
The bias is depending on the cooling capacity of your chassis, with a maximum of 30W per MOSFET. Or 55 Celsius at the heatsinks.
More bias is staying longer in class A.
That's all there is to it.

Walter

 

[2 picoDumbs]

both options are mono chassis.
1 set of diyaudio boards supports 4 pairs of output devices for 2 monoblocks.
If i want 8 pairs if output devices, 2 sets of boards are needed.

David

If you do 2 sets per channel you could build a balanced version with huge power output using existing transformer.
Approximately 60^2/8 ÷ 2 = 225W per channel (majority of it in AB). You could bias for 50W class A

 

[motorica]

Hi David,

I built a v3 also at 32 V, there is no power increase with more outputs. Only more power when you increase the PSU voltage.
With 8 outputs you can spread the heat better and that is a great advantage!
The bias is depending on the cooling capacity of your chassis, with a maximum of 30W per MOSFET. Or 55 Celsius at the heatsinks.
More bias is staying longer in class A.
That's all there is to it.

Walter

Thanks Walter!

This is the answer i opted for.
I will buuilt the v3 version (cascoded jfets) monoblocks enclosures.

My present speakers are easy to. drive (vs unifield one) so i don't need that much of a power, even standard F5 will. do. (and less energy will be wasted).

But I'm thinking of the future speakers so v3 is my choice.
Later on if i need more power i can replace the transformers to. 35vac and re-bias (caps are 63v).

Thnks!
David

 

[2 picoDumbs]

Thanks Walter!

This is the answer i opted for.
I will buuilt the v3 version (cascoded jfets) monoblocks enclosures.

My present speakers are easy to. drive (vs unifield one) so i don't need that much of a power, even standard F5 will. do. (and less energy will be wasted).

But I'm thinking of the future speakers so v3 is my choice.
Later on if i need more power i can replace the transformers to. 35vac and re-bias (caps are 63v).

Thnks!
David

If you want more power. Best solution is bridged/balanced version as mentioned above.
Requires no changes to your existing transformer.

 

[MASantos]

If you do 2 sets per channel you could build a balanced version with huge power output using existing transformer.
Approximately 60^2/8 ÷ 2 = 225W per channel (majority of it in AB). You could bias for 50W class A

Where do you get the 60^2 from?