Yes - the location of the devices on the heatsink is absolutely no problem whatsoever. I can run the F4 at higher bias than suggested in the F4 manual.
Great drawing pidesd !
🙂There's a far better way to exploit that idea - see Chris Hornbeck's proposal (post #148):
http://www.diyaudio.com/forums/tubes-valves/189153-phase-splitter-issue-3.html#post2802454
For one of possible practical renditions of that circuit see attachment. CCSs (Q5,Q6) should be matched to provide the same current (15mA) by means of R5,R15. P1 sets the DC offset.
Attachments
Juma,
At first glance, I would think that outputs would not be symmetrical, with the negativee half having a greater amplificationfactor. Not arguing, just don't really understand.
The positive half would appear to have no gain, coming out of the source pins of the FE.
At first glance, I would think that outputs would not be symmetrical, with the negativee half having a greater amplificationfactor. Not arguing, just don't really understand.
The positive half would appear to have no gain, coming out of the source pins of the FE.
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Buzz, let me help you understand: there are no halves, it's the same circuit as in LSKpre thread. If you omit all the spectacular stuff (complementary pair, folded cascodes, biasing, etc...) essentially you'll have a JFET with Rs=Rd ie. R6=R9 (condition for A=1) and one output taken from the source and the other from the drain, just like the simple cathodyne phase splitter.
It's true that outputs won't be absolutely equal but the other way around (negative phase will be 2-3mV lower) due to the fact that Rs includes internal resistance of JFET but it's easy to adjust it by adding a few Ohms to the value of R9.
Also, the Zout of both outputs won't be absolutely equal but with the load that is high enough (10k or more) it won't matter.
It's true that outputs won't be absolutely equal but the other way around (negative phase will be 2-3mV lower) due to the fact that Rs includes internal resistance of JFET but it's easy to adjust it by adding a few Ohms to the value of R9.
Also, the Zout of both outputs won't be absolutely equal but with the load that is high enough (10k or more) it won't matter.
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Maybe +OUT can be the input signal +IN instead of that indicated [cleaner], and then tweak -OUT by measurement to make it equal in amplitude.
Great drawing pidesd !
There's a far better way to exploit that idea - see Chris Hornbeck's proposal (post #148):
http://www.diyaudio.com/forums/tubes-valves/189153-phase-splitter-issue-3.html#post2802454
For one of possible practical renditions of that circuit see attachment. CCSs (Q5,Q6) should be matched to provide the same current (15mA) by means of R5,R15. P1 sets the DC offset.
Hi Juma,
Is this circuit being suggested as appropriate for adding a pot on the +/- outs to make it a "pre" for a balanced F4, or is it being considered as a *replacement* of a balanced F4 front end so that it can be driven by a single ended unity gain buffer preamp?
Big E,
i m not sure 100% of what you mean, but the phase splitter posted by juma is a unity gain buffer.
i m not sure 100% of what you mean, but the phase splitter posted by juma is a unity gain buffer.
Specs for pcb & fet mounting hardware
Can anyone point me to a source for pcb & fet mounting hardware,
and the part specifics, for the stores Deluxe 4U "Jack of all Chassis"?
I've had the pcbs and parts for over a month and would like to
build this thing.
Can anyone point me to a source for pcb & fet mounting hardware,
and the part specifics, for the stores Deluxe 4U "Jack of all Chassis"?
I've had the pcbs and parts for over a month and would like to
build this thing.
The Hardware is all M3. The RCA are fairly standard. The Speaker posts are Daytons.
PM me for more info. 🙂
PM me for more info. 🙂
Actually it gives close to 6dB gain - for 1V SE input you'll get about 2V balanced (~1V per phase).
Finally...Pics of the Fugliest F4 in the world!
Ok, Fugliest in the world in my opinion! 😉
I know my power supply approach is probably a bit unorthodox, but I ruined my PD boards with a stupid mistake. I was going to buy more, but this worked and the amp is dead quiet and sounds great. My 845 amp is driving the F4, which is providing power to the MTM portion of my VSA VR-35s. It sounds wonderful at normal levels at which I listen (75-85 db). However, when I crank it, I am quick to understand that my next project will be a higher wattage amp! The pics are not that great, but you'll get the idea: I am a novice with zero chassis building talent. Thanks for all your help (even though you didn't know you were giving it to me!)
https://picasaweb.google.com/117221555538051805236/DIYF4Amplifier?authuser=0&authkey=Gv1sRgCM7q4svVubmt3QE&feat=directlink
Ok, Fugliest in the world in my opinion! 😉
I know my power supply approach is probably a bit unorthodox, but I ruined my PD boards with a stupid mistake. I was going to buy more, but this worked and the amp is dead quiet and sounds great. My 845 amp is driving the F4, which is providing power to the MTM portion of my VSA VR-35s. It sounds wonderful at normal levels at which I listen (75-85 db). However, when I crank it, I am quick to understand that my next project will be a higher wattage amp! The pics are not that great, but you'll get the idea: I am a novice with zero chassis building talent. Thanks for all your help (even though you didn't know you were giving it to me!)
https://picasaweb.google.com/117221555538051805236/DIYF4Amplifier?authuser=0&authkey=Gv1sRgCM7q4svVubmt3QE&feat=directlink
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for all your help (even though you didn't know you were giving it to me!)
Next time turn your heatsinks around 😀
Fins to the Left, Fins to the Right, You're the Fugliest Amp in Town!
Yes, I knew you folks would pick up on that mistake right away. It adds a certain je ne sais quoi don't you think? 😉
Yes, I knew you folks would pick up on that mistake right away. It adds a certain je ne sais quoi don't you think? 😉
Maybe it is all right the way you have it; provided the suggested heatsink temperature is not exceeded. As you have it, heatsink temperature is probably uniform through out versus some gradient with the alternate fins perpendicular to the chassis; because cool air enters at the bottom, rushes upward across the fins and emerges as a hot wind at the top. Fortunately, as you listen to your diyF4 you will be doing the experiment.
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