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#461 | |
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One Seriously Addicted to Audio and Electronics
diyAudio Member
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Quote:
![]() (just to put things in perspective: that's not all of them.... )Ray. |
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#462 | |
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Magneto the Gravity Man
diyAudio Member
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Quote:
Hi. Another tube I want to try is PC900 - small size triode Andy |
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#463 | |
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diyAudio Member
Join Date: Jan 2006
Location: London
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Quote:
Ta ra i off to oceana, bye bye guys |
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#464 | |
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diyAudio Member
Join Date: Sep 2005
Location: DK
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Quote:
Hi Ray.. Yes it has, mainly a thicker baseplate. I think bluetag and bitumen are gonna do the job just nicely. I just start unsolder the standard. btw, ok picture ![]() /avr |
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#465 | ||
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diyAudio Member
Join Date: Dec 2003
Location: Berlin, Germany
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Hi all,
I tend to go for the multipcb offering: Their toroid is 70mm dia. / 37mm height and specified with 35VA. Even their 50VA toroid is only 75mm dia. / 38mm height (and probably only € 2-3 more)... Right now, we are only using 27VA with our specifications. Should we change this? Quote:
Still, until now no one from the US seems to be interested... Quote:
![]() I understand that 17V AC secondaries turn into something around 23V DC when you consider ripple and diode drop. But since we load the 200mA windings with only 35mA, I would still expect the DC voltage to be higher: A toroid this size has a regulation of 16% when unloaded. How much of this regulation remains when it is only partially loaded? (I have no idea...)
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Brutalized by bass and terrorized by treble... |
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#466 |
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diyAudio Member
Join Date: Dec 2005
Location: Doncaster England
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AVR300 - SE as the reference cd player. mmmm.
The SE has quite a lot of improvements over the standard player, most caps around the dac ,op amps and Hdam are elna silmics and cerafine. and the 4.7 ohm resistors are changed to 5% types on power rails etc. The tx is also improved with better caps on psu The hdam has copper shield and there is the chassis braise + extra damping plate on the bottom of player. So you can use this as a reference or mod it. It will be easy to get the standard 63 past these levels by changing a few critical components, so I would change these bits on the SE and get bigger gains I often do very simple mods (output caps , opamps , hdam , a few caps and resistors) to SE players and they become sooooo much better than the KI in standard form, infact you would think the SE was twice the price.
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#467 |
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One Seriously Addicted to Audio and Electronics
diyAudio Member
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Hi avr,
My point exactly. You should use the improved chassis of the SE for your modded version. Ray. |
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#468 | |
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One Seriously Addicted to Audio and Electronics
diyAudio Member
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Quote:
This is the reason I pleaded for a smaller tranny in the first place, instead of a 50VA. As we don't really need the power, the voltages are going to be a bit higher. How much is going to be a guess. Let's assume that if we load it with half the power, the regulation is going to be like 10%?? Then we would get 18.7VAC from the 17VAC winding. The peak value is 18.7*1.4142 = 26.4VDC. Minus two diode drops (1.4V) leaves 25VDC. But since there's always a load connected it's going to sag, and will probably say below 24VDC. It's a theoretical value, if your mains voltage is a bit higher, it could be above 24V, if you use smaller caps it will be lower. Personally I don't have a problem with it, since my regulators can handle 35...40VDC input. We could tune the voltages down a bit to be sure. How do the others feel about this? I don't think we should change the tranny to 35VA, since that will only make this effect worse. It's not a problem to have a slightly more capable core. Regards, Ray. |
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#469 |
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diyAudio Member
Join Date: Dec 2005
Location: Doncaster England
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I think we should stay @ 20V so that everyone can use the TX. We all have different regs/reg pcbs.
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#470 |
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Magneto the Gravity Man
diyAudio Member
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hi.
Bigger VA, Lower Off-load voltage = Better Regulation = Better PSU If a bigger VA toroid is available for a few cents more and it will fit, then this is the better option. It does not matter whether discrete or 7805-type regulators are used, the whole idea of a psu is to provide a stable output voltage, regardless of the load conditions. The psu will not perform to its best if an inadequate Tx is used ( like the oem!!!) The idea or replacing the Tx must be considered to be part of the rebuilding of the PSU section along with diodes, caps, pre-regulator if required etc. For those worried about the offload voltage, you can always use an (extra) preregulator - it will NOT degrade performance. Andy PS Lower noise is a beneficial by-product of PSU regulation! |
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