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5AR4 vs 5U4 rectifiers in Cary SLI-80

SET12 said:
Wish I had the opportunity as you have!
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I'll be the first to admit that it's an opportunity that no one in their right mind would pass up. I try and make myself useful from time to time, and then learn as much as I can every chance I get. Maybe when I retire in 8 or 10 years, I will have learned enough to be able to supplement my income with amp building projects, but for now, I'm happy sitting at the feet of one of the true masters of the art...:ntwrthy:
 
analog addict said:
Maybe when I retire in 8 or 10 years, I will have learned enough to be able to supplement my income with amp building projects, but for now, I'm happy sitting at the feet of one of the true masters of the art...:ntwrthy:
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:yes: That's my plan as well.

Dennis was very inspiring for me, I met him once at a Chicago Audio club meeting back in the early 90's and a couple of audio shows. Hearing his 2A3 a first for me nearly had me in tears and I told him so. He replied "That's Powerful Stuff!"

When I think back to when I pulled a EL84 single ended console amp out of a trash pile. I spent about 10hrs reverse engineering it. Today with such a circuit, I can visualize the same circuit on a wall from my mind. And today I'm designing circuits such as these 1.6 watt EML45 Monoblocks. That bring great such great pleasure to my friend and AKer jdg123 who built them. While there is some $3000 in parts, he tells me they have been his dream in sound reproduction. Real monsters 3ft by 3ft for the pair.

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SET12
 
I am really enjoying this thread. You guys have some amazing stories/pics, and I am learning quite a bit so far. Forums like these definitely make this hobby more fun and are a huge help to somewhat newer guys like me. I have only been dealing in tubes for a couple years. Before that, it was vintage SS Mcintosh equipment for me....Great gear, but man I love the sound of tubes :yes:

Thanks to everyone who has commented in helping me with my rectifier choice for the SLI-80. I'm gonna order a pair of Sovtec 5AR4's just to try for fun, and be watching out for a nice pair of NOS 5U4GB tubes. I am getting the feeling it's hard to go wrong with the 5U4GB's. I don't want to sacrifice any power by staying with my current Phillips 5R4GYS. Some have said the difference in voltage with this tube could drop my power/dynamics/etc.
 
dsd-7 said:
I'm gonna order a pair of Sovtec 5AR4's just to try for fun, and be watching out for a nice pair of NOS 5U4GB tubes. I am getting the feeling it's hard to go wrong with the 5U4GB's. I don't want to sacrifice any power by staying with my current Phillips 5R4GYS. Some have said the difference in voltage with this tube could drop my power/dynamics/etc.
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dsd--for what it's worth, I compared the Sovtek 5AR4 to the Shuguang 5AR4 and I thought the Shuguang sounded quite a bit better--more neutral and better extended on the high end. The Sovtek is okay, but the Shuguang was better. You may find differently, just FYI. Maybe consider the Shuguangs as an inexpensive backup since they are about the same price as the Sovteks. Neither of them compare to the Philips 5R4's, however.
 
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I did notice the Chinese tubes as another option to Sovteks. Like you said though, I'm sure neither of these will compare to NOS. I just would rather try a new production (cheaper) 5AR4 before fully committing to this type tube with an expensive NOS. If I really like the sound of the 5AR4, then I will probably look for a NOS pair. Thanks for your suggestion.
 
Perhaps the BEST rectifier for this application is the Sylvania MIL-SPEC 5931 (Military 5U4G). Has the lowest noise floor I've heard from a rectifier tube to date.
 
5U4G has more voltage drop than a 5U4GB though, and will tend to have more sag than a GB in an application that specified a GB. I haven't tried that particular Sylvie tube but I have tried 5U4G's in place of a 5U4GB in my Magnavox 9300 and after attempting to ignore it, I finally gave in to the fact that it sounded mushy and put the right tube back in. A voltmeter on the B+ line clearly showed the sags under heavy bass passages, which is where it sounded mushy. The 5V4G it currently runs is better though. Higher voltage, so I had to tweak a few resistors in the power supply but the B+ supply is rock solid and its got cleaner bass than it had with any of the 5U4G or GB types I tried.
 
I am going to try a pair of GZ37s next to replace the GZ34s.

What I learned today from Cary tech support is that the 2 rectifiers work in parallel and that you can run the amp with only one of them (but you could be short of power).
 
dminches said:
I am going to try a pair of GZ37s next to replace the GZ34s.

What I learned today from Cary tech support is that the 2 rectifiers work in parallel and that you can run the amp with only one of them (but you could be short of power).
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Wow, I had no idea that you could run 1 rectifier tube since they were ran in parallel (not that I would ever do that). You are talking about the SLI-80 correct?
 
dsd-7 said:
Wow, I had no idea that you could run 1 rectifier tube since they were ran in parallel (not that I would ever do that). You are talking about the SLI-80 correct?
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Yes. I was having an issue and he told me to power up with only 1 rectifier to make sure it wasn't the tube. I could have tested the tube so that wasn't necessary but he told me that only 1 rectifier was needed.
 
Having them in parallel gives double the current handling capacity. If the amp doesn't pull more than one tube can handle, you're perfectly OK doing that if they are wired in such a way that both tubes act as a full wave rectifier. Sometimes you'll see the tubes wired so each is a half wave rectifier. When its like that, you can't pop one out.
 
Ah, ok. Now that makes sense gadget73. I guess if Cary tech support said it was ok to try the one rectifier, it would be ok. I plan on always keeping two in the amp, but good knowledge none the less.
 
Excellent thread. Have recently purchased an SLI-80 Sig dating from 2005 and very pleased with it after being quite disappointed with the McIntosh MA2275.

Freo-1 said:
Perhaps the BEST rectifier for this application is the Sylvania MIL-SPEC 5931 (Military 5U4G). Has the lowest noise floor I've heard from a rectifier tube to date.
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Am running a pair of NOS JAN Sylvania 5U4GBs and quite pleased with their performance. Am thinking I need to pick up a pair of the NOS JAN GE 5R4GYs to give a try.

Analog Addict - what is Dennis Had up to these days now that Cary is in his past?
 
MX117.MC7150 said:
Analog Addict - what is Dennis Had up to these days now that Cary is in his past?
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He's building SE amps again, generally SEPs and SE beam tetrodes. I just got an e-mail from him a few minutes ago. I'm heading over to the shop this afternoon to pick up an amp he trouble shot for me, and listen to his new "Fire Bottle" high output 6BQ5 amp.

Here's some more info...

As for your original question, I'd roll every 6SN7 I could find through it. I have a huge pile of them, and you can PM me if you might like to see what exactly what I have.

Dennis is fond of 274Bs, the current ones made in China. He also uses 5V4s, 5U4s, 5AR4s, etc. He knows the voltage drop of all of these tubes, and as mentioned before in the previous thread, just plunks them in and out of his amps with apparent carelessness, but you can bet he knows exactly what he's doing....

BTW, if your ever in the RTP, NC area, let me know, and I'll take you by his shop. He's a genuinely nice guy, and loves to show off his latest creation.....
 
Thanks for the update. Very interesting read. Used his Soliloquy speakers 20yr ago and thought the 5i and 5.2 were excellent.

battradio said:
With that much capacitance a 5AR4 would crash and burn . As an example the three different tubes will give three different B+ reading with the same voltage in .

5U4GB 427 volts , 5R4G 411 volts and a 5AR4 462 volts . I would stay with the 5R4G , they are tuff old beasts.
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Good stuff.
Would the GZ37 be the same as the 5AR4?
 
Actually, was asking battradio about the B+ voltage with the GZ37. Am hoping he will run his modeling program for same to compare to the 5U4GB, 5R4G and 5AR4 calcs he ran.
 
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