I just got a Denon TU-800 and on the fmtunerinfo website JohnC has posted his component upgrades to take the tuner to the next level.
one of his upgrades is 6 Schottky diodes in the power supply section.
Power Supply
D703/704/710/711/712/713 - 11DQ10 Schottky diodes
C716 - 3300/25
C709 - 33/35
C703/710 - 47/25
C701 - 68/35
C705/708 - 470/50
C704 - 100/50
https://www.fmtunerinfo.com/DIY.html#TU-800
I have done a bunch of reading and do not understand how using Schottky diodes in this case will upgrade the tuner.
Can someone help me understand.
TIA
one of his upgrades is 6 Schottky diodes in the power supply section.
Power Supply
D703/704/710/711/712/713 - 11DQ10 Schottky diodes
C716 - 3300/25
C709 - 33/35
C703/710 - 47/25
C701 - 68/35
C705/708 - 470/50
C704 - 100/50
https://www.fmtunerinfo.com/DIY.html#TU-800
I have done a bunch of reading and do not understand how using Schottky diodes in this case will upgrade the tuner.
Can someone help me understand.
TIA
No reverse recovery, lower (forward) dissipation?
But there's a gotcha that you have to be careful about which is high reverse leakage, which can lead to thermal runaway in some situations and I'd never simply substitute Schottkys like this in a relatively high voltage circuit without careful analysis of the worst case thermal behaviour - Shottky's may need heatsinks to prevent this. Plain diodes just run hot without reverse leakage creeping up to milliamps, so leakage dissipation is never an issue.
But there's a gotcha that you have to be careful about which is high reverse leakage, which can lead to thermal runaway in some situations and I'd never simply substitute Schottkys like this in a relatively high voltage circuit without careful analysis of the worst case thermal behaviour - Shottky's may need heatsinks to prevent this. Plain diodes just run hot without reverse leakage creeping up to milliamps, so leakage dissipation is never an issue.
Hello,
Well, using Schottky diodes is supposed to lessen the RF generated when the diodes switch with the AC coming in. Pretty likely in a properly designed power supply that filters out any RF, there is little or nothing to be gained. Now marginally filtered and poorly designed power supplies, there they may help. Also, the audio circuit should be far enough away from the power supply (or shielded) that any RF is not getting into it. Again, good design makes a difference. IMHO.
Regards,
Greg
I replaced the diodes to Schottky in my Marantz ST-54L tuner. It brought an improvement, but at the same time I also experienced some distortion. Probably it should be aligned again, could be related to the AFC.
Compared to slowish snap-recovery diodes, schottky's are certainly an improvement in a tuner environment, but compared to the almost universally available slowish, soft recovery diodes used nowadays they probably have more potential to create switching noise (very small when rectifying slowly varying waveforms like the mains, but present nonetheless).
Basic rule: if something ain't broke, don't fix it. Just look at the innumerable stories of recapping going badly wrong for example
Basic rule: if something ain't broke, don't fix it. Just look at the innumerable stories of recapping going badly wrong for example