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Old 16th January 2002, 04:50 AM   #1
richt is offline richt  Puerto Rico
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Default hexfreds vs. regs diodes

folks

i installed superfast hexfred diodes in my amp and
there is big improvments in the transients but
sometimes i notice some harshiness in the top end.

if anyone had the same experience????????????????????

thank you
richt
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Old 16th January 2002, 10:34 AM   #2
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I have researched (theoretically only, no listening tests yet) diodes and have decided to standardize on IRF 15ETH06 http://www.irf.com/whats-new/nr001005.html (For low voltage stuff I expect I will standardize on a shottky). The unit is marketed as "Hyperfast" and "very soft-recovery". A noble marketing message if ever there was one + the datasheet looks nice.

These units are 600V which is more than adequate for my needs. Higher voltage units are available in similar series, but this particular model is quite new.

My philosophy at this point is to check out the data sheets and make an informed decision. Your mileage may vary.

Petter
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Old 25th February 2003, 10:11 AM   #3
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Default Hyper fasts are the go!

My friend can't stop raving about these rectifiers...one of the cheapest places to get them is www.future-active.com although MOQs are usually 50. Get a few friends together and go for it. I had enough gumption to just put an order through myself...

He was using the RHRG3060s and similar types.

From their website:

1. Mfr. Part #: RHRG3060
Future Part #: RHRG3060
Vendor: FAIRCHILD
Package Qty: 30
In Stock

View Similar Parts 30 - 90: 1.254
120 - 150: 1.199
180 - 210: 1.177
240 - 270: 1.155
300+: 1.134

Dirt cheap:
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Old 25th February 2003, 12:31 PM   #4
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I finally did some diode comparison tests yesterday and here's what I found: http://www.diyaudio.com/forums/showt...303#post134303

Basically my findings about hexfreds are confirmed with the above comments.
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Old 25th February 2003, 04:41 PM   #5
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Default Re: hexfreds vs. regs diodes

Quote:
Originally posted by richt
folks

i installed superfast hexfred diodes in my amp and
there is big improvments in the transients but
sometimes i notice some harshiness in the top end.

if anyone had the same experience????????????????????

thank you
richt
-----------------------------------
Have a look at the wave form using a wide band say 100MHz scope and see if you have a nive traingular shape, or if there ia a lot of hf hash. In that case try a snubber cap.,0.01uf across eaxh diode. Pl post your findings.
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Old 15th May 2008, 01:52 AM   #6
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Default diode and cap placement

Hello Richt; Could you please sketch a diagram of what you mean by ".01 cap across each diode"? I am having a difficult time trying to conceptualize this in my stressed out brain. Would you do this for each diode if you were making a full wave bridge?

Thanks, Andy
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Old 16th May 2008, 12:52 AM   #7
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put each cap in parallel with each diode is what he meant. this reduces the RF noise generated by the diodes. for a bridge rectifier, this would require 4 0.1uf caps.
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Old 17th May 2008, 04:06 AM   #8
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Default snubbed diode bridge?

Would this be what you mean? I just want to make sure before I use my last fuse!

Cheers,
Andy
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Old 17th May 2008, 10:30 AM   #9
AndrewT is offline AndrewT  Scotland
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no,
you have paralleled two of the diodes with caps, but not the other two.
You should also experiment with adding resistors in series with each cap to create a real snubber (damped RC) rather than rely on the very low ESR that is inherent in some caps.
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Old 17th May 2008, 03:08 PM   #10
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Yeah, I still don't know how to wire them. Could someone make a crude drawing, snap a picture of it and upload it here? This would greatly eliminate confusion for me.

Thanks for all of the excellent help!

Andy
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