Best 100$ that I had spent on my Audio System


I had enjoyed my Line Magnetic 508 integrated to drive Lansche 4.1 speaker.

Even with stock tube, LM 508 was better than retubed Rogue Cronus Magnum II with open and more dynamic sound.

But I got bothered by somewhat bright presentation of LM 508 with stock tubes.



When I had replaced stock SL7 tubes with 1944 RCS Nos SL7, sound got much more neutral.

https://www.ebay.com/itm/Vintage-1944-RCA-JAN-6SL7GT-VT-229-Tube-Tests-Good/112606823278?ssPageName=...


After few more tube rolling, I am using Sl7 Nos Brimar which I am happy with natural and transparent sound.

https://www.ebay.com/itm/True-NOS-Gain-Tested-Brimar-England-CV1985-6SL7GT-Vacuum-Tube-Brown-Base/12...



I also had replaced stock SN7 with Amperex SN7(Bugle boy) the sound got more natural with more bloom and details.

https://www.ebay.com/itm/PAIR-OF-6SN7GTB-AMPEREX-TUBES-NEW-6SN7-NOS-NIB-Vacuum-Tubes-Bugle-Boy/26392...

I had been happy with "Bugle Boy" for a while, this is a steal for the money.


But after noticing right channel sounds slightly louder than left channel, I had decided to replace Bugle Boy with Bad Boy (1944 Sylvania VT-231 ) yesterday.


Holy Cow!

Sound got much more dynamic with wider soundstage.

Also some siblance that I noticed after placing bells behind my speakers are gone.

"Bad Boy" battered "Bugle Boy".


Bugle Boy is a pretty good tube with nice details and overall balance but it could not match the dynamics and open sound of Bad Boy.

As I like Bad Boy, I ordered one more tube as spare from the same source.


This time he charged 125$.

NOS SYLVANIA JAN CHS 6SN7GT (VT-231) chrome top Black 3 hole Tplates | eBay



I had used Accuphase DG28 digital equalizer for room correction for 15 years.


With Bad Boy in LM 508, the sound is so open and dynamic that it sounds more natural without room correction.


Thus 100$ Bad Boy bumped Accuphase DG28 digital equalizer that I had paid 10K 15 years.


100$ Bad Boy brought more than twice improvement over that brought by Synergistic 150$ Blue fuse.


This is the best 100$ that I had spent on my audio system.

100$ tube bumped 10K digital equalizer.


Thomas
128x128shkong78
@lowrider57

Thanks a lot for useful information.

By the way I have more than 4 tubes for 6sn7 and 6sl7.

I also have ultimate best 300B, that is, original Western Electric 300B made in 1930

Matched pairs of them cost 6k or more.

Thus I am reluctant to put them inside LM508.

I am going to do tube rolling one by one.

It will take several months to finish it.
RCA made so many variations of each tube type. Plus the sonics varied over time from the 1940s up to the 70s. Some have a tubby bass, some have a tight bass with a very open sweet midrange and the Cleartops have a extended airy top-end. 
RCA is one of the best built and dependable tubes.

Here's a great reference from a great dealer. I linked to 6SN7 so you can see how many there are available. Also check out 6SL7's, but there aren't as many.

http://www.audiotubes.com/6sn7.htm


@lowrider57

Thanks for your advice.

I know that it could be hit or miss in Ebay

So far, I have not had any problem.

I check their rating and acceptance of return.

I believe in my hearing.

All the tubes appears to be genuine.

But not all NOS tube sound fantastic.

For example, RCA SL7 that I tried gave tubby and veiled sound although not bright.

But I will keep trying to find gem in Ebay.


The Mark Baker belt (Origin Live) for my Townshend Rock 7. Cost...under $30.00 shipped. Wowrerzzers!
The Sylvania VT-231/6sn7GT is loved by many tube rollers for its airy highs, and open 3D imaging. Some of the Bugle Boys are known to have an extended top-end with a "sting" and possible sibilance.

It seems like you got lucky with a genuine NOS pair of Sylvanias. But buying on Ebay is risky. Your Bugle Boys were not made in Canada, but could have been imported from Holland or US. There's also the chance that they were not manufactured by Amperex but were rebranded tubes. And they possibly were not NIB or matched since one channel was losing strength over time.

Great news that you found the right tubes. But buyer beware on Ebay.