Rectifier tubes?

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Re: Rectifier tubes?

Postby rmyauck » Thu May 02, 2013 9:24 am

Add the diode mod found on the tubes4hifi sticky on their form. Use UF4007 as they are only a few cents more and a newer , quieter faster diode. Whoever buys it won't come back to you short either with a premature 5AR4 failure.
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Re: Rectifier tubes?

Postby Blair » Thu May 02, 2013 11:25 am

All it is is 1N4007/UF4007 in seriess with the red leads?
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Re: Rectifier tubes?

Postby Geek » Thu May 02, 2013 7:59 pm

Better mod - gives the same voltage drop as a GZ34 ;)

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Re: Rectifier tubes?

Postby Blair » Thu May 02, 2013 8:49 pm

That's a nice mod and looks like it will handle S*#t ton of current:)

I was just going to try to sell this amp as a "returned to original" type amp. Is there anything really wrong with the GZ34?

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Re: Rectifier tubes?

Postby Geek » Fri May 03, 2013 4:18 am

No. GZ34 is a great tube (y)
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Re: Rectifier tubes?

Postby rmyauck » Fri May 03, 2013 11:35 am

It's just taxed a bit high so will help any of them last much longer, and especially new ones which fail early so the diodes in series help. No one will even know they are there as the advantages of the slow warm because of the RAR4/GZ34 is kept. It will also help when the power flashes off and on in a power interuption.

This is a handy way where the spare tube pins are used to mount the diodes. If you want to hide them just put them in series to pins 4 & 6 with the correct orientation and put shrink wrap over them.


http://dynacotubeaudio.forumotion.com/t ... -diode-mod
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Re: Rectifier tubes?

Postby joeriz » Sun May 12, 2013 7:33 pm

I have a question about the "diode mod". If this mod is done, does one get the same effect as moving to "pure" solid state rectification (i.e. a bit more power, "tighter" bass)? Also, once the diode mod is done, does one even need the rectifier tube anymore if one is not concerned about having a "soft" start?

Thanks,
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Re: Rectifier tubes?

Postby kheper » Tue May 14, 2013 5:48 am

joeriz wrote:I have a question about the "diode mod". If this mod is done, does one get the same effect as moving to "pure" solid state rectification (i.e. a bit more power, "tighter" bass)? Also, once the diode mod is done, does one even need the rectifier tube anymore if one is not concerned about having a "soft" start?

Thanks,
Joe


The diode mod makes the rectifier a hybrid (solid state/tube). The ss diodes increase the voltage and current handling capacity of the rectifier, but the tube provides soft-start and the tube sound is retained (a hybrid should sound less harsh than with just ss diodes). Better current handling, soft-start and tube rectifier sound, all for the price of 2 ss diodes.

You can go with a pure ss diode rectifier at ~450Vdc without worrying about damage to the cathodes, but you need to make sure that your caps can handle the extra voltage, since there is less of a voltage drop with ss diodes than with a tube rectifier.

Below are examples of hybrid, Full Wave bridge rectifiers. Most think that soft-start is needed for high(er) voltage (> ~800Vdc) applications:

http://www.lundahl.se/sidor/hybrid_power.html

http://web.archive.org/web/200706121922 ... ifier.html
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