Dennis Had Inspire Amps

[Masterlu]

Isaacc7... Welcome to AA!

[Analog Addict]

Originally Posted by joel_hifi

Input driver tube - it came with the GE NOS 6SN7 GTB, is there any other tube that would possibly better that one?

Thanks!

There are lots of choices for "better" 6SN7 tubes, but only your ears can tell you which. However there are many highly regarded choices available. For vintage tubes, look at KenRad, Sylvania, RCA, Tung Sol. In general, the older the better. Anything marked VT-231 is a military tube, and typically also desirable. WWII vintage tubes command a premium, especially the metal based Sylvania 6SN7W tubes. Do a search on everyone's favorite auction site for "6SN7 tube" and use the advanced function to look at the sold items. There were NOS pairs of the metal based Sylvania 6SN7W tubes that went for $350-$450. Also, google "6SN7 reviews/shootout". Lot of opinions out there....

[FloridaBoy]

Originally Posted by Bombadil

I own 5 different 5AR4 / GZ34 rectifiers. In both my SE HO and my PSE amp, all five sound exactly the same to my ears.

It is changing the 6SN7 tube where I hear differences.

I *think* the PSE amps are directly heated rectifiers only. Analog? Straitwire?

[FloridaBoy]

Originally Posted by joel_hifi

Bombadil, Bentan, many thanks for your kind feedback

Rectifier tube - well noted, so no much difference between various 5AR4/5U4/5Y3... would you say it's also true/same for 274B?

Input driver tube - it came with the GE NOS 6SN7 GTB, is there any other tube that would possibly better that one?

Thanks!

Are you driving the Omega CAM speakers with the Inspire?

[joel_hifi]

Originally Posted by Bentan

Hi Joel_hifi, to be clear , there are differences between the different types of rectifier tubes because they have different voltage drop. From what I know, for instance, the 7581A should not be used with the 5AR4. I’ll leave the explanation to the more experienced and knowledgeable guys around here. What I meant was that there are no audible differences to me across different brands of the SAME rectifier tube types.

I have a bunch of 6SN7 but I haven’t got around to rolling them yet.

Yes no problem, I did get the Output/Rectifier Tube Cross Reference chart with the amp, I was also referring to the sonic/audible differences

I wanted to check if rollers could also share their experience about the 274B tube, does it make any sonic/audible difference vs. the 5AR4 when used with KT88s?

[joel_hifi]

Originally Posted by Analog Addict

There are lots of choices for "better" 6SN7 tubes, but only your ears can tell you which. However there are many highly regarded choices available. For vintage tubes, look at KenRad, Sylvania, RCA, Tung Sol. In general, the older the better. Anything marked VT-231 is a military tube, and typically also desirable. WWII vintage tubes command a premium, especially the metal based Sylvania 6SN7W tubes. Do a search on everyone's favorite auction site for "6SN7 tube" and use the advanced function to look at the sold items. There were NOS pairs of the metal based Sylvania 6SN7W tubes that went for $350-$450. Also, google "6SN7 reviews/shootout". Lot of opinions out there....

Thanks a lot for all your good suggestions

[Isaacc7]

Originally Posted by Masterlu

Isaacc7... Welcome to AA!

Thanks! Apparently I had an account already since my computer prompted me with the password. Don't think I've ever posted before though.

[joel_hifi]

Originally Posted by FloridaBoy

Are you driving the Omega CAM speakers with the Inspire?

Correct, a very good match. I'll report some more on the Inspire amps and which speakers thread.

[Bombadil]

Originally Posted by FloridaBoy

I *think* the PSE amps are directly heated rectifiers only. Analog? Straitwire?

They can run either directly or indirectly-heated rectifiers. The noise floor is slightly higher with indirect. I run direct ones nearly all of the time, but did test out my indirect rectifiers, as noted earlier.

All of my 274B / 5U4G type rectifiers sound the same to my ears too. I must have 7 or 8 of them. I use them interchangeably in my amps, selecting one over another solely for aesthetic reasons. I like big rectifiers when I run big power tubes and use smaller ones with smaller power tubes.

The old vintage "used but still good" ones that I picked up for $5-$10 each sound the same as more highly sought-after ones which sell for $100+.

[Bombadil]

Hard to say which 6SN7 variant will be best to your ears. People have different preferences.

I've tested out about 25 different brands and years. My two favorites are 1960s Westinghouse 6SN7GTB tall copper rod and a 1940s Raytheon VT-231. Close behind are some 50s and 60s Sylvania, but I haven't had a chance to listen to the famous Sylvania Bad Boy 6SN7GT 3-hole black plate, copper grid. These were only made for 18 months in 1951-1953. Many other Sylvanias from the 1940s and later 50s are advertised as Bad Boys but are not the real McCoys.

I do have a new Psvane CV181-T MkII, which has received rave reviews and liked by many in the online forums. I found it to be good, but not great. I like a big open soundstage with good detail. This tube produced a smooth, pleasant sound while a bit softer on highs and a slightly diminished soundstage. I understand why many like it.

As to the VT-231 tubes, these are "military" in name only. The military wanted their common tubes to adhere to their inventory numbering system. So companies simply started labeling their standard production 6SN7 tubes as VT-231. No changes to the tube itself. However if it is labeled as a VT-231 then you are assured that it is an old tube made in the 1940s.

Years later the military started demanding strict low noise standards and long life and tubes which passed these tests were designed as "JAN" or "USN" military spec tubes. Some believe, and many dealers promote, the earlier VT type tubes as being similar and having passed more rigid testing, but they weren't.