5751's.....

The Secret Weapon?
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5751's.....

Post by !KANT » Thu Mar 24, 2005 11:42 am

Man oh man....these RCA Commands are rare and when you do find 'em.....woooooweeeee they hit ya hard with the price [$100 to $150] a pop. I've been doing some tube searching and been researching about "rolling" [not only with regards to VooDoo Audio, but HiFi audio aspects as well. Now I'm looking at other manufactures of 5751's, other than RCA. Sylvania JHS series and Tung-Sol are also on the list--these are up there in friggin' price too. Let's see what happens as I do more (re)searching....

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The Commands are the Best, then there are the rest...

Post by Voodoo Guru » Thu Mar 24, 2005 6:37 pm

The "RCA Command Series 5751 Black Plates" are by far the Best sounding Tube for VooDoo Audio. They have the Richest, Low End Harmonics that you will find in any other tube.
There are a few that are real close. The closest to the RCA Commands are the "GE 5 Star Triple Mica Grey Plates". W5UDX has compared the 2 tubes extensively and he said the differences are VERY minimal. The Commands have a tad more colored Harmonics...but it is so hard to tell, that we doubt if you would here it over the air. There is also some minimal differences in the High Frequency area.
Another good substitute are the "RCA 5751 Triple Mica Black Plates" around the 1950's era. The are a notch under the GE 5 Stars. They are not all that expensive either.
We have a set of the Prized Holy Grail "Sylvania Gold Series JHS-5751WA Triple Mica Black Plates". They are a matched pair and we spent $180.00 for them, which was actually a steal. They are a wonderful sounding tube. For Music, they are by far the best tubes. But for the application that we put them in, Voice...the JHS are My second choice. The RCA Commands have more Robust, Richer, and Thicker Harmonics. The Sylvanias have a Mid range warmth and a spectacular High Frequency smoothnes, yet ultra crisp. They just don't have the Commands Low Frequency Harmonics that slap you in the face and make you take notice. They don't call them "Command" for nothin!!
We don't like the "Tong Sol" tubes, not even for music applications. They are too Brassy, and are lacking in the Low Frequency area.

"Tube Rolling" is an art. Most people don't have the "ears" to notice the differences and sonic characteristics in the different tubes. We have had so called "Audio Engineers" tell us "There is absolutely no differences in the tubes when it comes to audio characteristics...only in the gain".
We got one word for them...BULL!
We can hear them, W5UDX can hear them, a whole Hell of allot of other Audiophiles can hear the differences.

We guess thats why we all like the Harmonics and the VooDoo, that We do, sooooooo weeeelllll!!
Last edited by Voodoo Guru on Fri Sep 18, 2009 2:56 pm, edited 3 times in total.
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Post by !KANT » Fri Mar 25, 2005 12:03 am

I knew I could get ya to respond straight and direct on this subject :lol:

Well, the reason I even found out about Sylvanias and Tung-Sol's is from reading about 'em and the differences--meaning someone out there can HEAR the difference. The RCA's are really highly sought after by MANY [domestic and foreign]. I figured even if I find just one I'll be content....not in a rush anyway. We'll, keep an eye peeled. As always, thanks for the guidance. :wink:

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Post by !KANT » Tue May 10, 2005 1:52 pm

Well, my hunt for [well priced] 5751's continued today. I got one hell of a lesson on tube types and manufacturers, including the type of business it was and the way it was conducted back then. I eventually felt comfortable enough to place an order and I did.

So now I have some RCA's coming in--actaully 4--and I look forward to getting them in here. It was interesting as hell, and the salesman was very knowledgable and took the time out of his day to explain it all. After 34 minutes on the phone the lesson was worth it.

There are many outlets to acquire tubes from, but pricing, customer service and warranties dictated my decision. eBay can be a little scary especially when you consider that these are much older tubes and no longer being manufactured. So the reliablity factor of the seller makes it uneasy to settle [even if they have a high rating]. Thanks to Greg for putting that outlet on the map for me. I think I'll be getting some more tubes over time from them just to experiment with--

:wink:

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Excellant!

Post by Voodoo Guru » Wed May 11, 2005 2:11 pm

Very Good!!!
You will not be disapointed.
Don't forget....they require about 50 hours worth of burn in time before the tube "Sound" stabilizes.

So as good as it sounds when you first put them in ......
it only gets.............

Smoooooooooother!
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Post by !KANT » Thu May 12, 2005 12:57 am

I was going to ask how long they need to be burned in. I ordered 2 Black Plates and 2 Grey Plates--I couldn't resist the price(s). He only had one Commader, but I wanted a pair. He did mentioned that the Sylvania Gold Series are rare 5751's and are his most expensive when he gets 'em. I really wanna hear the difference before rolling 'em--to appreiciate the sound more when I do. :twisted:

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Got em

Post by Voodoo Guru » Thu May 12, 2005 6:22 am

Yes, the Sylvania Gold Label are a very fine tube.
We have a Pair here.....very expensive.
We paid $180.00 for a matched pair....and that was a steal.
There are 2 different kinds though,
There are:
1) the Sylvania Gold Series with the Gold Pins
2) the Sylvania Gold Series without the Gold pins but has a Gold Label with Black Plates and triple mica insulators. Their number is JHS 5751WA and all the writing on the tube is in Gold. (wipes off REAL easy!). These were Government issue tubes.

#2 above is the Rare one. we got 2 of those as a matched pair.
They sound wonderful and musical, but they just don't have the Low End Harmonics that the RCA Command Series does.
We have made comparison recordings between these tubes.
We'll put them in here when we have the time.
Last edited by Voodoo Guru on Fri Sep 18, 2009 2:56 pm, edited 2 times in total.
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Tube Comparison

Post by Voodoo Guru » Thu May 12, 2005 4:25 pm

Ok Ya'll,
Here is an audio clip of the Tube Comparison Recordings we made during the Tube Rolling.

The First pair of tubes you will hear in the Clip are "RCA 5751 Triple Mica Black Plates".
The Second pair of tubes are the "Sylvania 5751 Gold Series Black Plate Government Tubes".
The Third pair of tubes are the "RCA 5751 Command Series Black Plates".

All three pairs of tubes were burned in for over 100 hours before the recordings were made.

All the Recordings were made with the Audio being Transmitted on a TS-850s/DSP-100 Combo and Received on another TS-850s/DSP-100 Combo, then recorded with Cool Edit Pro on the Hard Drive.

The Microphone was a Sennhieser MD421.
The rack at the Time was as follows:
Bellari RP520 Studio Tube Microphone Preamp
Behringer SNR2000 Denoiser
Bellari RP533 Studio Tube Multi-Processor
Behringer DEQ2496 Ultracurve Pro
Behringer EX3200 Ultrafex Pro
Behringer DSP2024P Virtualizer Pro

We know, We know..Not the "Rack from Hell" we got now....but it worked wonderfully at the time

The Tube Rolling was accomplished in the Bellari RP533.
That was it..just the tubes were changed.
Absolutely no settings were messed with during the tests.
That includes Gain, EQ, Compressor or anything else....
Just the tubes.
You will hear a bit of Downward Expander "Breathing" due to us not changing any settings and the amount of background noise we had at the time.....so don't concentrate on that....just listin to the difference in the way the different Tubes "Sound".

Enjoy....

http://www.wz5q.net/mp3/5751tuberolling.mp3

One, Two.......da VOOOOODOOOOOOOOOOOOOOOOOOOOO!!!!
Last edited by Voodoo Guru on Sat Mar 24, 2007 8:31 am, edited 2 times in total.
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Post by !KANT » Fri May 13, 2005 1:36 am

Belive it or not I prefer the sound of the RCA Black Plates...though the Commanders definitely had a slightly more pronounced harmonic sound.... I wish you had a test with the Grey Plates.... :wink:

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Oh Hell....

Post by Voodoo Guru » Fri May 13, 2005 7:02 am

Yea, we wish that too.
We have some now, but not at the time these comparisons were done.
We would have to roll all the tubes out again due to all the different equipment we have now, not to mention the modifications that were accomplished on the rack gear, to get an accurate comparison.

We might do that after we get moved in to the riverhouse on a slow Tuesday.

Hmmmm....
interesting choice of tubes.
Why is that?

We'll email you the complete recordings for further evaluation.
Last edited by Voodoo Guru on Sat Mar 24, 2007 8:33 am, edited 1 time in total.
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Post by !KANT » Sat May 14, 2005 1:19 am

I got 'em and now I'm magnetized to the Sylvania Sound. After a few hours it's so damn smooth...my god... :shock: Well for the next few days I'll be keeping these units on just to burn-in the tubes.

The tubes did arrive today....just that the box was stuck in the mailbox, so my wife waited for me to get it out [since it said "tubes" on the package]. So I figure I'll get 'em in over the weekend and let 'em run their pace....

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Short Tube Life

Post by Voodoo Guru » Sat May 14, 2005 9:28 am

Be careful with the Sylvanias.
If you listin to the recordings, there are two of them.
The Sylvania 100 hour is the last recording. That smooth sound changed again after the tubes burned in for a week.
One of the Problems with the Sylvania Gold Series Government 5751 Black plates with the silver pins is that they tend to go flat fairly fast.
We have read on the internet that they flatten out quicker than any other 5751 tube.

Tube Rolling is sooooo much FUN!!
Now you too can VooDooooo with the Sounds of Tubage!!!!
Last edited by Voodoo Guru on Sat Mar 24, 2007 8:34 am, edited 1 time in total.
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Post by !KANT » Sat May 14, 2005 6:18 pm

Yeah babyyyyyyy!!!! :D

Just wondering, is it recommended not to run 'em--any tubes--consistantly if the units are not in use???

Black Paltes are in and the Gray Plates are in the other unit, and both units have been on for the past 5 hours. I have no intension of turning them off for the next few days.

I don't intend to use the Gold Series, but I will experiment with others. One day the Commanders will be in this as well.

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Smoothness in the EQ

Post by Voodoo Guru » Wed May 18, 2005 9:07 pm

It has always been our understanding that turning them "on" and "off"
is where the damage occurs, due to the inrush current on the filaments.
Also if the tubes have been "off" for an extended amount of time, the internal "Gas" seems to leach from the "getter" halo, or sometimes outside gas will migrate into the tube.
This is one reason why it is good to keep them turned "on", also why they require such a long "burn-in" time when new. You have to have them on with High Voltage on the Plates to energize the "Getter" halo. This pulls out all the Gas in side the vacuum tube.

We can't wait until you get the command series in there to here them yourself.
Last edited by Voodoo Guru on Sat Mar 24, 2007 8:35 am, edited 1 time in total.
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Post by !KANT » Fri May 20, 2005 12:59 pm

Well thank you for clarifying this for me--I've been turning them off every morning before "leaving the lab". I'll keep both of 'em on [thought the '53's lights will probably burnout a lot quicker than I want them to. I did notice over the course of them being on for a few days, there definitely was some warmth and depth to the sound....really really nice. I can only imagine how much more I'll be impressed with the Commands--I believe I don't need 'em, but I can always keep the thought... :twisted:

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Post by SawzAll » Sat Jul 24, 2010 3:45 am

Anyone have some thoughts on the "Black Sable" line of tubes?
They seem to have a following... :o

I have a stack of 12AX7's, some 7025's, and I found one 5751 'Made in Holland" in the bunch from my past days in music/studio. Also found two Tungsram/Hungarian-made tubes. Plus a "Groove Tube" 5751 and 7025. I knew that saving those tubes would be needed some sunny day.

I just wonder if putting that Holland/5751 tube in my Behringer Ultra Gain Pro 2200 mic preamp would be wasting time.
Or is it worth the time to try it?
Would you?
:?:
Thoughts?

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Post by Voodoo Guru » Sat Jul 24, 2010 4:14 am

Never had any of the Black Sables in the equipment to be able to give any thoughts on them.

The MIC2200 uses what they call a 'Starved Plate' circuit for the tube. It only uses about 30 volts on the plate. They just use it for some small type of tube effect.

You can try replacing it, but don't expect much of a difference.

Take Care,
Last edited by Voodoo Guru on Sat Aug 24, 2013 11:09 am, edited 1 time in total.
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Post by !KANT » Thu Jan 27, 2011 2:25 pm

And it's a BAWL-Biter to get to that tube in the '2200... :evil:

[Mine sitting in the box in the corner with other processors I no longer use :oops: ]

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Post by ECC82 » Sat Jun 22, 2013 12:34 pm

Some nice 5751 photo's in this Ebay ad
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... ink:top:en
Pure tube porn :wink:
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Post by ECC82 » Sat Aug 24, 2013 10:22 am

Bought a 5751 on German E-bay, 15 euro's. Could see on the photo that it had black anode plates, it's an RCA and when I compared it to an RCA Command it looks like a twin brother, most of the orange paint is gone. It tested good on the tube tester, so nice purchase. That is one thing European tube manufacturing companies should have learned from the American companies: make sure the tubename/type stays on the tube. Most European made tubes lose their paint/print and than it is almost impossible to determine type/brand.
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