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Rectifer Tube Choice for easy on the other components.............

107.2.79.94

Posted on April 1, 2021 at 16:53:19
Cut-Throat
Audiophile

Posts: 15432
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
I had a pair of Korneff Clone Monoblocks built that pretty much match the following schematic.. B+ was lowered to 275 Volts, but otherwise it is pretty much identical. I have a question on the rectifier tube. The Builder said that I could use the 5U4G or 5Y3G or 5R4G among others... I don't need a lot of power out of this 45 amp, as I Bi-Amp and the 45 amp is only used on my 115db Horns. My question is what Rectifier Tube would be the easiest (Put the least stress) on other components on the Amp such as the Transformers, Tubes and Capacitors? I have tried the 5U4G and the 5Y3G Tubes and to my ears the 5Y3G sounded a bit better.











 

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RE: Rectifer Tube Choice for easy on the other components............., posted on April 1, 2021 at 19:26:10
Eli Duttman
Audiophile

Posts: 10431
Location: Monroe Township, NJ
Joined: March 31, 2000
Forward drop in 5Y3s is large. You may be hearing the reduction in B+ rail voltage.

If, as the schematic suggests, you're taking the "raw" B+ from pin 8 of the rectifier socket, try a Bendix/Red Bank 6106. It's a variation on the 5Y3 theme that is constructed with a cathode sleeve. Vacuum rectifiers with cathode sleeves exhibit slow B+ rail rise.

BTW, the original use for 6106s was in Nike SAM systems. Bendix/Red Bank is THE epitome of rugged and reliable.


Eli D.

 

If you like a 5Y3..., posted on April 2, 2021 at 05:59:42
Steve O
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Posts: 10288
Location: SE MI
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...you might also like a 6087. It's an indirect heated version of the 5Y3 with essentially the same characteristics. Personal experience indicates slightly less voltage drop compared to std 5Y3 but with much slower warmup. These should be both more available and lower cost than the coveted and overbuilt Bendix Redbank stuff.

 

RE: If you like a 5Y3..., posted on April 2, 2021 at 06:34:03
Eli Duttman
Audiophile

Posts: 10431
Location: Monroe Township, NJ
Joined: March 31, 2000
Yes, the 6087/5Y3WGTB is nice. I've used 'em.


Eli D.

 

RE: If you like a 5Y3..., posted on April 2, 2021 at 11:03:54
baileyler
Audiophile

Posts: 353
Location: Chadds Ford, PA
Joined: January 17, 2007
You could also try a GZ30 or a Euro 5Y3GB. Those are both actually 5Z4, which I understand to be a 5Y3 with an indirectly heated cathode.

 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 12:22:38
Cut-Throat
Audiophile

Posts: 15432
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
Just to clarify... Are you saying that the 5Y3G Tube is putting more stress on my other components in the Amp than the 5U4G tube?






 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 14:40:18
Eli Duttman
Audiophile

Posts: 10431
Location: Monroe Township, NJ
Joined: March 31, 2000
A 5Y3 yields a "shorter" B+ rail than a 5U4. Good, bad, or indifferent will depend on the specific situation.


Eli D.

 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 14:59:19
Cut-Throat
Audiophile

Posts: 15432
Location: Minneapolis - St.Paul Area
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Thanks for your reply.... What exactly does a 'Shorter B+ rail' mean? -- And how is that different from what the 5u4G tube does?

And I not talking about Sonics here. I am talking about Stress on the other Components such as the 45 Tube, and the Transformers etc.....






 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 16:59:24
Eli Duttman
Audiophile

Posts: 10431
Location: Monroe Township, NJ
Joined: March 31, 2000
The forward drop in 5Y3s is larger than that in 5U4s. Therefore, rectifying with a 5Y3 gets you fewer B+ volts than rectifying with a 5U4. What sort of an effect the "shorter" B+ rail has will be situation dependent.


Eli D.

 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 17:10:19
Cut-Throat
Audiophile

Posts: 15432
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
So, it won't hurt anything?






 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 2, 2021 at 18:07:35
samstone
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Location: midwest inner city
Joined: August 11, 2002
I vote for the 5y3.

 

Thanks, posted on April 2, 2021 at 23:15:31
Cut-Throat
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Posts: 15432
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
An answer!






 

A More Detailed Answer, posted on April 3, 2021 at 06:18:53
FlaCharlie
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Location: Gville, FL
Joined: June 1, 2003
When the builder said it was OK to use either the 5Y3 or the 5U4 I'm sure they were thinking in terms of how much B+ voltage the circuit would see as a result. Both of them drop quite a bit of voltage and the resultant B+ is in the range the builder suggests.

The exact voltage drop will vary depending on the circuit but the data I've seen indicates a 60v drop for the 5Y3 and 44v for the 5U4. So the 5Y3 will result in slightly lower B+, but the builder said either one is fine.

Of the two, the 5Y3 will stress the amp less because its heater only draws 2A, while the 5U4 draws 3A.

The other factor is fast vs slow startup. Both the 5Y3 and the 5U4 are directly heated which means fast startup. If you want to minimize stress, slow startup is preferable. Some versions of the 5Y3, such as the 6087 and others listed earlier, are indirectly heated versions which will give you a slow startup.

So the least stressful would be one of these indirectly heated versions of the 5Y3.

There are other indirectly heated 5v octal rectifiers, most notably the 5AR4, but they drop considerably less voltage and the resultant B+ would be higher than the builder suggests, so it should not be used.

 

Thanks, Exactly the explanation I was looking for !, posted on April 3, 2021 at 06:54:22
Cut-Throat
Audiophile

Posts: 15432
Location: Minneapolis - St.Paul Area
Joined: September 2, 2000
Also, the Amp builder said that a 5V4G could also be used in my 45 Korneff Clone Monoblocks. And since this is an indirectly heated tube, I am thinking that this may have the slow start up characteristics and may stress the amps less. His actual comments on the 5V4 vs. the 5U4 were as follows.

"I think the 5V4 will be fine. The 5U4 can is capable of handling more current draw, like 200 mA, compared to the 5V4 that can handle up to 150 mA. Each block only draws about 40-50 mA so you will be okay. 5V4 also drops less voltage which will add slightly more to the plate voltage on the 45."

Thanks Again!







 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 5, 2021 at 03:59:35
PakProtector
Audiophile

Posts: 11965
Joined: May 14, 2002
It is a matter of how you describe 'stress'. The DH models like 5R4, 274, 5Y3 and 5U4 are all DH, and deliver voltage almost instantaneously. If this is an issue, then an IDH would be called for. If it is a matter of voltage output, then the higher resistance models like 5Y3 would be called for.

There is another IDH 5Y3-ish tube, type 6087.
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: Rectifer Tube Choice for easy on the other components............., posted on April 5, 2021 at 05:06:33
vacuumtube1954
Audiophile

Posts: 233
Joined: December 24, 2009
PakProtector hello and agree with you. I remember asking the late Don Garber about using the Bendix 6087 in my Fi and he stated that he thought it was the finest for use in the 5Y3G section. Slow start-up and tough as nails.

 

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