Lampizator Valve / Tube Rolling Review Thread

[Bobofei86]

Glad you bought those the 2nd link was wrong!

Now removed, but I noticed it sold. I have a spare so if you bought it on my recommendation contact me and I'll send it to you if you pay postage. Sorry about that!

Don’t worry, I noticed that after I placed the order for that single tube
Then I found the link and ordered that VU71 pair, target to receive them by end of Aug

 

[Jazzhead]

The RK 5u4g was my fav Recti in the PAC , but pole position has been now taken by the Takatsuki 274b , vastly more refined and a much higher resolution, works great for me alongside the RK242s

 

[Bobofei86]

For me it is the exact opposite.

IME the AME 274b is an "effect" tube (very airy, but hollow in the mids and lean in the upper bass) that I use to compensate for fat and rolled off in the treble output tubes, like the NOS GEC KT66 for example.

The RK 5u4g is very linear and transparent but also robust sounding.
I still like the RK 5u4g very much.

I got another RK5u4g to test again and this time it blows my mine

It sounds simliar to GZ480 and much better than ACME, excatly the same description given by Christoph, my RK sounds so harsh and likely it's a faulty unit. Kudos to Christoph and WBF ?? i think i can get a new RK5u4g as GZ480 backup

 

[cpcat]

Another nice recti for me- National Union JAN/vt244/5u4g

Interesting that the NU is actually quieter for me than the USAF 596 -by a fair margin of at least 5db -measuring background hum at full volume. Gain measures the same. I thought the increased noise level might be due to a gain difference at the output between the two different rectis but that isn’t the case.

 

[christoph]

Another nice recti for me- National Union JAN/vt244/5u4g

Interesting that the NU is actually quieter for me than the USAF 596 -by a fair margin of at least 5db -measuring background hum at full volume. Gain measures the same. I thought the increased noise level might be due to a gain difference at the output between the two different rectis but that isn’t the case.View attachment 80900

and how does it sound?

 

[highstream]

Another nice recti for me- National Union JAN/vt244/5u4g

Interesting that the NU is actually quieter for me than the USAF 596 -by a fair margin of at least 5db -measuring background hum at full volume. Gain measures the same. I thought the increased noise level might be due to a gain difference at the output between the two different rectis but that isn’t the case.

Since presumably you don’t listen at full volume, perhaps measuring the noise difference at intermittent points, starting with nothing playing, would be more definitive. The single full volume measurement also assumes the noise difference is linear.

I’ve only heard a pair of National Union 6F8G‘s. Very decent but nothing special. I still find the RCA JAN CRC 5R4GY up to 1945 to be the best I’ve used in my TRP.

 

[cpcat]

and how does it sound?

At the risk of sounding like an objectivist (which I am not) I am not really convinced yet that I can tell a difference between rectifiers with regards to sound quality. I assume though that if I can measure lower noise (and my gain has not changed which I can also measure), then the noise floor is lowered. This should then result in blacker background and improved low level detail.

 

[cpcat]

Since presumably you don’t listen at full volume, perhaps measuring the noise difference at intermittent points, starting with nothing playing, would be more definitive. The single full volume measurement also assumes the noise difference is linear.

I’ve only heard a pair of National Union 6F8G‘s. Very decent but nothing special. I still find the RCA JAN CRC 5R4GY up to 1945 to be the best I’ve used in my TRP.

This is a valid point- however I am already at the lower limits of what I can measure with my rat shack SPL meter at max volume on the DAC. The meter‘s lowest setting is 60 db and the meter reads --2db (58db) at max volume with the microphone/meter on the floor touching the bottom of the speaker with the NU rectI. For comparison the reading is 64db with the USAF 596.

 

[highstream]

Do you have a phone or tablet? The NIOSH Sound Level Meter app is considered about the best around -- https://www.cdc.gov/niosh/topics/noise/app.html. I've done well enough holding an iPad Mini either on my lap or directly in front of my face at the listening position. As long as the position is consistent, good comparisons can be made.

 

[cpcat]

Wow, thanks. how easy was that. I feel like a real 21st century guy now.
I should be able to get a few more measurements and report back.

 

[christoph]

At the risk of sounding like an objectivist (which I am not) I am not really convinced yet that I can tell a difference between rectifiers with regards to sound quality. I assume though that if I can measure lower noise (and my gain has not changed which I can also measure), then the noise floor is lowered. This should then result in blacker background and improved low level detail.

If you can't hear a difference in sound quality between different rectifiers, what is the purpose of your "hunt"?
1 or 2 dB less noise?

 

[cpcat]

If you can't hear a difference in sound quality between different rectifiers, what is the purpose of your "hunt"?
1 or 2 dB less noise?

Well - I guess mainly for the fun of it. What is the purpose for your hunt?
Are we getting philosophical now?

I do believe there are sound differences among rectifiers - I think they are probably subtle though assuming everything is functioning correctly.

And yes, background noise is important to me-I use one of the analog inputs on my DAC as a HT input and need to run it at approximately unity gain -so it can be audible and even distracting from from my listening position if it isn’t mitigated.

3db is 50 percent less noise, 2db around 35 percent less. It is logarithmic so certainly isn’t insignificant-but that may not be the whole story either.

 

[highstream]

Chasing rectifiers to find one or two that help the system satisfy sonically is not fun for the most part, but the necessary and costly overhead of owning good quality tube gear. Fun is finding the one(s) that work for me; the rest is frustration. If for some reason you can’t hear the differences, save your money and time for what you can hear.

 

[christoph]

Well - I guess mainly for the fun of it. What is the purpose for your hunt?

Only sonics

 

[christoph]

Chasing rectifiers to find one or two that help the system satisfy sonically is not fun for the most part, but the necessary and costly overhead of owning good quality tube gear. Fun is finding the one(s) that work for me; the rest is frustration. If for some reason you can’t hear the differences, save your money and time for what you can hear.

Fully agree

 

[cpcat]

Well, if anyone is interested, here are more noise measurements on 4 different rectifiers using the NIOSH sound meter app as suggested.. As it turns out, Highstream is correct in that the noise measured at high volume setting doesnt behave linearly and likely doesn’t impact what you hear at normal listening levels, nor even at unity gain, but rather only at much higher levels.

The 4 below are highest to lowest noise, measured and pictured left to right-USAF 596, NU vt244/5u4g, RCA 5u4G, and stock Svetlana 5u3c. The output tubes are 4 WE 101FA’s and I hot-swapped the rectis and allowed a few minutes to stabilize for each measurement.

A pic of the measurements on a note pad follows that. The vc setting is the left column. My ambient room noise is around 30db. Unity gain on my balanced B7 is around -20b to -25db on the VC from what I can tell in setting up my B7 to run as HT bypass on one of its analog inputs. As you can see any rectifier noise has faded into ambient noise at around that level for all 4 tubes. This could vary somewhat I would suspect with speaker sensitivity, balanced vs single ended operation and also likely with output tubes. So many variables!

For what it is worth, I am still liking the sound of the NU 5u4G at the moment—very much.

 

[dminches]

I have been spending a good amount of time with the WE 300B reissues in my Pacific and I really like them. I haven't found any weaknesses in terms of over tonal balance. Now that I am very familiar with their sound I am going to try some different rectifiers. Currently I am using the Tak 274B.

 

[AMR / iFi audio]

So many variables!

But compared in a very clear and orderly manner. Individual measurements are always engrossing. Do you mind elaborating a little bit on the method of your test? To be more precise, I am interested to know about the tools you've used to get your measurements?

You've got very nice handwriting, by the way

 

[cpcat]

But compared in a very clear and orderly manner. Individual measurements are always engrossing. Do you mind elaborating a little bit on the method of your test? To be more precise, I am interested to know about the tools you've used to get your measurements?

You've got very nice handwriting, by the way

Well, it’s not very elaborate at all. For years I have used an old analog Radio Shack spl meter for level measurements in my various systems as they have evolved (slowly, as I don’t buy gear often). I have measurements going back over 20 yrs and 3 houses. I use the bass decade on the Stereophile test CD (I now have it ripped to the hard drive) as a reference for attempting to optimize the bass response in my room.

As I integrate my HT with my 2ch system I have always needed a “home theater bypass“ for my front 2 channels - basically a switchable analog passthru on the preamp for the L/R channels coming from the HT processor. After getting my new Lampi B7 this required me to configure one of the analog inputs at approximately unity gain so that I can continue to enjoy both HT/multichannel and 2ch as before -I am using the B7 (with volume control and added analog inputs) as a preamp. This means one analog input set to a fairly high volume on the B7 (which accentuates any background noise/hum if present). So, for me it is important to have the lowest noise possible- even with the B7 vc at higher settings -and I have experimented quite a bit in trying to accomplish that.


Recently, very recently, another member here (Highstream) suggested I try the NIOSH SPL meter app as an alternative to the old SPL meter that I have :

‎NIOSH Sound Level Meter

‎This award-winning app combines the best features of professional sound level meters and noise dosimeters into a simple, easy-to-use package. - Developed by experienced acoustics engineers and hearing loss experts. - Completely FREE – No ads, no limited features, and no in-app purchases. -...

apps.apple.com

Initially, I would measure the noise on the analog input at the 0db setting on the vc , without signal playing, as a reference for noise. However, following Highstream‘s suggestion with the newer SPL meter app I have also measured at various other levels on the vc and found the noise to be similar among the rectifiers I have on hand (less difference, but not identical) at lower levels.

I simply place a phone or tablet running the app at the base of the speaker at the selected vc setting to make the measurement.

 

[MOME]

I have been spending a good amount of time with the WE 300B reissues in my Pacific and I really like them. I haven't found any weaknesses in terms of over tonal balance. Now that I am very familiar with their sound I am going to try some different rectifiers. Currently I am using the Tak 274B.

I can only agree with what has been said. Although I have tried many driver tubes, including NOS ones, the new WE300b are my favourites.
As for the rectifier tubes, I would like to share my personal ranking in combination with the WE300b:

TOP:

USAF 596 "The Accurate“
Tak 274 b "The Harmonic“
Osram U52 "The Vocalist“

MID:

RCA 5U4G
KR 5U4G
KR 274b

LOW:

ELROG 274b
Siemens CV 717

I am already curious about your experiences