tms0425 said:
Hi,
We were discussing the T0-220 style transistor housing. The entire back of the transistor is metal, as well as the mounting tab. If you attach the transistor to the heatsink with a metal screw (without isolation) you're connecting the drain to the heatsink thus defeating the mica pad.
I'm going to go out on a limb here and suggest that the Zen #9 has a 'fatter' bass sound due to even harmonics. The F4 would sound leaner by comparison. I don't have a spectral analysis to point to, and I don't have either amp running to listen to. Just looking at the schematics.
Or I could just point to the LU1014D and make fatuous comments about its clear superiority...
Grey
Or I could just point to the LU1014D and make fatuous comments about its clear superiority...
Grey
I am just in the process of buying the parts for two F4 to be used in Mono. I have read through the thread, but to be honest, I am not clear on some advises, so please help to clarify:
1. Power-transformers:
From the Schema I understand that we need 2*18V for one channel. Papa stated that 300VA is what he used.
But what does this now mean exactly:
- One 300VA-Transformer for both channel with 4 windings each 18V, so that the two channel are seperated ?
= 4 Windings or two TRansformers for Stereo, two bridges, two full capacitor banks
- Or is the standard-design not a Mono-Psu per Channel, which would mean in the F4 the same Winding is used for both Channel ? = 2 Windings 18V for Stereo. one bridge, but two capcitor banks
- Or even the same two capacitor-bank are used for both channels ?, so one psu and the same +/-23Volts go to each channel ?
2. For Stereo:
- I guess ideally both channels are completely separated, as well in the PSU, so independent windings, bridge rectifiers, capacitors, right ?
- So ideally, even two transformers in one enclosure for one F4 / two channels, Right ?
Soooo....
- IS this as well still vaild if I don't want to use it as a Stereo-Amp, but use it as a Mono-Block ? Instead of 4 Windinge / two Transformers: Would be One TRansformer / two windings (and one following bridge / one capacitor-bank) be enough ?
...in the case of stereo the channel separaton is important, everybody knows this, but in the case of amplifing the negative and positive half of the same wave: Is this still the same requirement ?
3. Has the LED any function on the circuit or is this only to show: "the amp is powered on" ? If it is really only for showing it is "on" I will skip it, if it is important to the circuit, which one exacty to buy ? I have not found a 645nm 1.6V, 1ma-Type...I you want to do me a favour, the farnell-parts-number wold be helpfull....
4. LAst question: The beauty of F4 is obviously the few parts in the signalpath...so I guess it would be helpful to get the best parts available...any suggestions ? HAs anyone played with this so far (normal Panasonic caps vs Blackgates, normal resistors vs Caddocks, standard bridge-rectifier vs Schottkies...)?
Thanks for your hints...
1. Power-transformers:
From the Schema I understand that we need 2*18V for one channel. Papa stated that 300VA is what he used.
But what does this now mean exactly:
- One 300VA-Transformer for both channel with 4 windings each 18V, so that the two channel are seperated ?
= 4 Windings or two TRansformers for Stereo, two bridges, two full capacitor banks
- Or is the standard-design not a Mono-Psu per Channel, which would mean in the F4 the same Winding is used for both Channel ? = 2 Windings 18V for Stereo. one bridge, but two capcitor banks
- Or even the same two capacitor-bank are used for both channels ?, so one psu and the same +/-23Volts go to each channel ?
2. For Stereo:
- I guess ideally both channels are completely separated, as well in the PSU, so independent windings, bridge rectifiers, capacitors, right ?
- So ideally, even two transformers in one enclosure for one F4 / two channels, Right ?
Soooo....
- IS this as well still vaild if I don't want to use it as a Stereo-Amp, but use it as a Mono-Block ? Instead of 4 Windinge / two Transformers: Would be One TRansformer / two windings (and one following bridge / one capacitor-bank) be enough ?
...in the case of stereo the channel separaton is important, everybody knows this, but in the case of amplifing the negative and positive half of the same wave: Is this still the same requirement ?
3. Has the LED any function on the circuit or is this only to show: "the amp is powered on" ? If it is really only for showing it is "on" I will skip it, if it is important to the circuit, which one exacty to buy ? I have not found a 645nm 1.6V, 1ma-Type...I you want to do me a favour, the farnell-parts-number wold be helpfull....
4. LAst question: The beauty of F4 is obviously the few parts in the signalpath...so I guess it would be helpful to get the best parts available...any suggestions ? HAs anyone played with this so far (normal Panasonic caps vs Blackgates, normal resistors vs Caddocks, standard bridge-rectifier vs Schottkies...)?
Thanks for your hints...
Blitz said:
You will find most of these answers in the first half of this thread.
Also, check out: WTB: F4 PCB boards - in the Trading Post forum of diyAudio Forums for more info about the power supply process. There is more than one way to use your power supply--it's your choice as to how complex you want to get.
Carpenter, I have read through the first half of the thread, but still my understanding is not clear from hat has been written. What is your recommendation ?
Beleive me, I would have not asked if I would got it from what was written, so please be a bit more co-operative than only to tell me that I should read it again...thanks for the effort & patience.
Beleive me, I would have not asked if I would got it from what was written, so please be a bit more co-operative than only to tell me that I should read it again...thanks for the effort & patience.
Blitz said:
1. It is the standard-design not a Mono-Psu per Channel, which would mean in the F4 the same Winding is used for both Channel = 2 Windings 18V for Stereo, one bridge, the same two capacitor-bank are used for both channels, so one psu and the same +/-23Volts go to each channel
2. Ideally, two transformers in one enclosure for one F4 would be nice
3. If you are referring to LED on front panel, it only shows if amp is ON and you can skip it.
Mike,
My brain has been eaten by the Cold Germs From Hell...there's something else that I should have mentioned above: Power supply.
Are the two amps running on more or less equivalent power supplies? It's not always easy to compare, especially if you're using different transformers, etc., but when in doubt throw another couple zillion uF into the filter. If can have a profound effect on the perceived bass response.
The Threshold S-500 came stock with 4 big computer grade caps, something on the order of 30000uF ea. Sounds like a lot. Worked pretty well. Then I got a wild hair and roughly doubled it to around a quarter-Farad per chassis. Improved the bass considerably. Just something to ponder as you're listening.
Grey
My brain has been eaten by the Cold Germs From Hell...there's something else that I should have mentioned above: Power supply.
Are the two amps running on more or less equivalent power supplies? It's not always easy to compare, especially if you're using different transformers, etc., but when in doubt throw another couple zillion uF into the filter. If can have a profound effect on the perceived bass response.
The Threshold S-500 came stock with 4 big computer grade caps, something on the order of 30000uF ea. Sounds like a lot. Worked pretty well. Then I got a wild hair and roughly doubled it to around a quarter-Farad per chassis. Improved the bass considerably. Just something to ponder as you're listening.
Grey
Peter, thanks. You are confirming what I was assuming...so the rela high-end-solution for a F4 is Dual-Mono Supply, so two Transformers for stereo or 4 Windings and two capacitor banks...
OK...
Last Question: What is your recommendation for a cost no object-monoblock ? As well complete mono-psus as described above or will that not really make a difference in your experience when amplifying the different halve of the same signal ?
OK...
Last Question: What is your recommendation for a cost no object-monoblock ? As well complete mono-psus as described above or will that not really make a difference in your experience when amplifying the different halve of the same signal ?