Hi All,
Getting close to finishing my dual mono F4 clone. It's only been powered up for about an hour and I was listening to it for 15 min or so. Sounds great with the tube pre-amp that is also mostly done. I'm going to let the F4 run a few hours on the bench and re-adjust the bias and offset in preparation for a full listening session tonight. HP339 is saying THD: ~0.0078% at 1 watt into 8 ohm. Real number is likely lower than that as I think the notch filter on the HP needs some work.
The case is the diyaudio deluxe 4u.
Anyway, thanks to Papa and everyone else for all the info you've posted to this site. Without it I'd still be listening to store bought stuff.
Getting close to finishing my dual mono F4 clone. It's only been powered up for about an hour and I was listening to it for 15 min or so. Sounds great with the tube pre-amp that is also mostly done. I'm going to let the F4 run a few hours on the bench and re-adjust the bias and offset in preparation for a full listening session tonight. HP339 is saying THD: ~0.0078% at 1 watt into 8 ohm. Real number is likely lower than that as I think the notch filter on the HP needs some work.
The case is the diyaudio deluxe 4u.
Anyway, thanks to Papa and everyone else for all the info you've posted to this site. Without it I'd still be listening to store bought stuff.
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every stereo F4 deserves proper XLR on back plate
Don't worry. 30 minutes with a saw and I can switch the RCA to XLR if/when I need to.
Here's a question for ya
Look at the second waveform in my picture, 1st post (1st waveform is 1khz input). This is the HP distortion monitor output. This the signal sent to the meter after the notch filter. See how much fundamental frequency is in the signal? Shouldn't that have been removed? and isn't it throwing my measurements off?
thx
Look at the second waveform in my picture, 1st post (1st waveform is 1khz input). This is the HP distortion monitor output. This the signal sent to the meter after the notch filter. See how much fundamental frequency is in the signal? Shouldn't that have been removed? and isn't it throwing my measurements off?
thx
Has anyone ever posted an F4 schematic with cascoded JFETs? This could be interesting to see alongside the recent F5 Turbo excitement. F4 Turbo V1?
This would be another way to raise the voltage, at least to the max voltage of the BA-3 front end, whether running balanced or SE.
Out of curiosity, would this be achieved by omitting R1-4, Q1-2, D3-4? What about C1-2, still needed?
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probably yes ; pretty trivial ( read - cut'n'paste jobie)
speaking of which schematic , exactly ?
I built my headphone amp using attached schematic - also added Jensen JT-123-ALCF as Nelson recommended as interstage transformer (posts 3397 -3400.)
I was just kindly gifted some 2Sk2013s and 2Sj313s. Can they replace the IRF510s and IRF 9510s? I have these currently biased at 350mA
As always thanks.
Bob
I was just kindly gifted some 2Sk2013s and 2Sj313s. Can they replace the IRF510s and IRF 9510s? I have these currently biased at 350mA
As always thanks.
Bob
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I may have to adjust R8 or R9 for biasing and R6 or R7 for offset. I ended up with R9 at 5k and R6 at 8k