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Old 29th December 2010, 03:09 PM   #5671
Salas is online now Salas  Greece
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Quote:
Originally Posted by nicoch46 View Post
found this for free , but need a beta tester......
I did it. I haven't heard anything different, but it did not do any damage either. My cart never saw some prolonged offset though since it was only hooked on Jfet input stages. Beyond the very limited time DMM test there is no suspicion it could have been slightly polarized.
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Old 29th December 2010, 03:17 PM   #5672
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Originally Posted by SGregory View Post
Here is something of interest regarding coax. I keep it close by to reference.
RF Cafe - Coaxial Cable Specifications Cables Chart

I use rg59/U at time since it is available at the local electric supply store when I need it.
According to the link RG49 have a Zo of 73-75 ohms of characteristic impedance, not ideal for analog transmission line but perfect for digital SPDIF....

I want to point about cables that all is reduced to have small capacitance, I remember one time I did a cable with 15pF meter & the sound was very very bad, thes is also other importants things like: inductance, shield, geometry, characteristic impedance, etc.....believe me guys It's not easy.
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Old 29th December 2010, 03:34 PM   #5673
Salas is online now Salas  Greece
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Quote:
Originally Posted by Joao@AltheaMusica View Post
Let's try something with the power supply for 2011. I can see that mostly a dual mono ps is used and I would recommend another version.

Use a stereo power supply for each stage:
a regulated, of course a Salas, low voltage ps for the first stage, another for the 2nd stage and a 3rd for the output stage.

I think that it's better to use a common supply, here called stereo, for each stage with has the same phase instead of a common supply for each channel.

My experiences with such a supply result in more inner detail and inner dynamic of music reproduction.
Individual regs per stage are best isolation of course. Have you done that with the phono and regs discussed in this thread, or its general experience?
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Old 29th December 2010, 03:37 PM   #5674
Salas is online now Salas  Greece
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Originally Posted by massimo View Post
Splitting each single channel PS into three is definitely a good idea, but I do mind the polar bear!
Let's take a 200+200 mA CCS setting: now becomes 600+600 mA or 1.2A in total. With 45 V, equals to over 50 watts power consumption for a stereo circuit drawing around 2 watts (AndrewT will rectify my math) that is 5 % (95% wasted!)
It can be done, I guess, using a single ccs set for 200-300 mA per channel followed by three shunt devices + error amps. Each new shunt circuits separated by low ohm resistors.
Many regs especially shunt are a royal luxury regarding efficiency, very true. That would not stop some hobbyists on the other hand, given the popularity of hot rod or class a. I wouldn't be much surprised to see a DIY phono in a sinks flanked medium size power amp case some day.
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Old 29th December 2010, 04:18 PM   #5675
massimo is offline massimo  Italy
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When too much is.... too much!
What do you think about the idea (credit to Andrew T) of one CCS followed by 3 shunts/error amps per channel?
R could be in the 3.3 - 4.7 ohm ballpark.

P.S. this can be done without changing the Xfrm (from 200 mA to 300 mA), but if you step onto 600 mA......
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Old 29th December 2010, 04:26 PM   #5676
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We have discussed that idea again in the past, maybe with Andrew and ZenMod also, must have been a multi reg query of a member about jfet active crossovers with many legs and functions, can't be sure I remember well. Sounds logical, though nobody gave any practical feedback in the end. So I don't know if it will have any practical difficulties to fix.
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Old 29th December 2010, 04:31 PM   #5677
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I read Andrew T's suggestion in the HV thread.
Thus we need another "beta tester"..... Maybe Joao would like to give a try
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Old 29th December 2010, 04:41 PM   #5678
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Old 29th December 2010, 04:51 PM   #5679
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...or Gregory when he will finish to shovel up!
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Old 29th December 2010, 05:04 PM   #5680
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That will be the spring!.
May consider building it though. I have some 1.5kW torroids laying around from an old Aleph Project
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