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Tube reviews in an amp

Rega

audiopro

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Hi

I decided to post my views and experiences with rolling different tubes. When I first started I had no idea about any tubes but over the past several months I have studied them and had the chance to own a few nos tubes as well. This article is posted here to make it easier for anyone else to get a grip on tubes without having to spend a lot of money or time.

First a bit about tubes.

On a basic level one has pre stage tubes and output stage tubes. Pre stage tubes are the ones that you usually hear about. They go with nomenclature such as 12ax7, 6922, 5687 and so on. The most famous are the 12ax7 series followed by the 6922 family.

A little about these two families.

The 12ax7 also has two sibling namely the 12au7 and the 12at7. The difference is that they all have different gain factors. Hence it is recommended to stick with the model that the manufacturer provides.

The 6922 is based on the 6DJ8 tube and is considered as a beefed up 6GJ8. It can be replaced in any circuit that used a 6DJ8 tube. Then there is a 7DJ8 which can also be used in most circuits but it uses a 7v heater rating. There is also a 6H23 tube which is the Russian equivalent.

Output tubes go by nomenclature such as higher output tubes like 211, 845, kt88, kt120 and lower output tubes like el84, 6L6 etc.

Now coming to the brands. There are various brands but I'll mainly divide them into NOS tubes and current production tubes.

Current production.

You mainly have 2 players here. The Russians and the Chinese. The Russians have bought the rights to many great brands such as sovtek, genelex, mullard where as the Chinese have brands such as JJ Telefunken Psvane etc. Except for psvane all the other brands are run off the mill tubes if they are new production. The sovteks can withstand a lot of abuse and hence many manufacturers use them in their pre stage. Basically when you buy any new tube Amp today you will have one of these tubes in it.

Now coming to the nos players. This is where the party begins. Telefunken, Amperex bugle boys, Philips mini watt, Mullard.

Telefunken.
They are considered to be among the best tubes out there. They are expensive. They have a ruler flat response. You won't have the typical tube sound with this tube. The mids are not fat nor is the bass bloated. Nothing sticks out yet everything is delivered when it's called for. It's not a euphonic tube but is extremely well balanced head to toe. It times well, has enough air, enough body, and extends at both extremes just enough. And it can boogie when needed. It will make your toes tap and make you dance. It's not an emotional tube that draws you in on some songs, but makes other songs sound boring. I'm using the cheapest nos 12au7 that I could find so I can only imagine how much better the medical grade tubes must be.

Amperex bugle boys

Once again there is a lot of variety available. I'm using the cheapest tube costing about 45 USD but these guys can get expensive.

This tube doesn't extend as much on top yet it doesn't sound rolled off. It's a bit dark on the top end and mainly focuses on giving a dry, slightly upfront mid band. The bass doesn't really stick out and is integrated into the mid band itself. Sounds nice on small bands. Imagine you have a whiskey in hand and there are 3 performers in a dark night club. This is exactly what this tube does. Very good for jazz etc. I'll call it the dark night club tube.

Voshkod 6H23

These tubes came stock in my audionote source so I switched them to nos amperex initially hoping for some magic. I was transported to the dark night club but on many other songs I felt I was missing out. I put the voshkod back and guys, this tube is the holy grail. It is THE most transparent tube I've heard. No hash, no artificial bloat, just one clean clean band if energy. This is probably why it didn't hit me when I first heard it. Good equipment doesn't draw your attention at first but with time one appreciates it. According to me this is how the perfect source should be. Transparent without emphasizing or deleting anything.
The only other player that did this was an old simaudio cd player that I tried many years ago. Nowadays far too many sources try to voice their products in a particular fashion, which makes them sound great on some songs and boring on others. The voshkod sounds neutral on anything you put through it letting the Amp or speakers deliver the boogie factor. At just 10 bucks a tube this is the steal of the century. Audionote picked it for a reason and this was it. Google voshkod rocket tubes if you want this fellow. He also has a bigger brother costing more.

Sovteks new production
Very mid heavy tube with a dark top end without bite. Sounds heavenly on stuff that has female vocals that tend to be bright but overall not a very good tube.

Telefunken new production
These are produced by JJ and are not even close to the nos tubes. These tubes are very transparent top to bottom but a little thin and bright with a slightly recessed mid band. Good tube if you will combine it with a nos tube in the same circuit.

I'm currently using this with the nos telefunken as I didn't have the budget to go all nos. It's main strength is that it is very transparent and doesn't really have a strong signature to impose on any other tube in the circuit.

I'll update this thread if I test anymore tubes. Hope it's useful to those who have tube amps and want to experiment a bit.

I'm using the audionote oto Amp and with the Telefunken NOS in it, it is one of the most satisfying amplifiers that I have owned.

Please note that before tube rolling check with the manufacturer or on forums regarding what can and cant be rolled. If the amp runs the tubes hard then only the new production sovteks may work over a long period.
 
Last edited:

murali_n

Well-Known Member
Joined
Dec 30, 2008
Messages
1,317
Points
113
Location
Chennai
Hi

I decided to post my views and experiences with rolling different tubes. When I first started I had no idea about any tubes but over the past several months I have studied them and had the chance to own a few nos tubes as well. This article is posted here to make it easier for anyone else to get a grip on tubes without having to spend a lot of money or time.

First a bit about tubes.

On a basic level one has pre stage tubes and output stage tubes. Pre stage tubes are the ones that you usually hear about. They go with nomenclature such as 12ax7, 6922, 5687 and so on. The most famous are the 12ax7 series followed by the 6922 family.

A little about these two families.

The 12ax7 also has two sibling namely the 12au7 and the 12at7. The difference is that they all have different gain factors. Hence it is recommended to stick with the model that the manufacturer provides.

The 6922 is based on the 6DJ8 tube and is considered as a beefed up 6GJ8. It can be replaced in any circuit that used a 6DJ8 tube. Then there is a 7DJ8 which can also be used in most circuits but it uses a 7v heater rating. There is also a 6H23 tube which is the Russian equivalent.

Output tubes go by nomenclature such as higher output tubes like 211, 845, kt88, kt120 and lower output tubes like el84, 6L6 etc.

Now coming to the brands. There are various brands but I'll mainly divide them into NOS tubes and current production tubes.

Current production.

You mainly have 2 players here. The Russians and the Chinese. The Russians have bought the rights to many great brands such as sovtek, genelex, mullard where as the Chinese have brands such as JJ Telefunken Psvane etc. Except for psvane all the other brands are run off the mill tubes if they are new production. The sovteks can withstand a lot of abuse and hence many manufacturers use them in their pre stage. Basically when you buy any new tube Amp today you will have one of these tubes in it.

Now coming to the nos players. This is where the party begins. Telefunken, Amperex bugle boys, Philips mini watt, Mullard.

Telefunken.
They are considered to be among the best tubes out there. They are expensive. They have a ruler flat response. You won't have the typical tube sound with this tube. The mids are not fat nor is the bass bloated. Nothing sticks out yet everything is delivered when it's called for. It's not a euphonic tube but is extremely well balanced head to toe. It times well, has enough air, enough body, and extends at both extremes just enough. And it can boogie when needed. It will make your toes tap and make you dance. It's not an emotional tube that draws you in on some songs, but makes other songs sound boring. I'm using the cheapest nos 12au7 that I could find so I can only imagine how much better the medical grade tubes must be.

Amperex bugle boys

Once again there is a lot of variety available. I'm using the cheapest tube costing about 45 USD but these guys can get expensive.

This tube doesn't extend as much on top yet it doesn't sound rolled off. It's a bit dark on the top end and mainly focuses on giving a dry, slightly upfront mid band. The bass doesn't really stick out and is integrated into the mid band itself. Sounds nice on small bands. Imagine you have a whiskey in hand and there are 3 performers in a dark night club. This is exactly what this tube does. Very good for jazz etc. I'll call it the dark night club tube.

Voshkod 6H23

These tubes came stock in my audionote source so I switched them to nos amperex initially hoping for some magic. I was transported to the dark night club but on many other songs I felt I was missing out. I put the voshkod back and guys, this tube is the holy grail. It is THE most transparent tube I've heard. No hash, no artificial bloat, just one clean clean band if energy. This is probably why it didn't hit me when I first heard it. Good equipment doesn't draw your attention at first but with time one appreciates it. According to me this is how the perfect source should be. Transparent without emphasizing or deleting anything.
The only other player that did this was an old simaudio cd player that I tried many years ago. Nowadays far too many sources try to voice their products in a particular fashion, which makes them sound great on some songs and boring on others. The voshkod sounds neutral on anything you put through it letting the Amp or speakers deliver the boogie factor. At just 10 bucks a tube this is the steal of the century. Audionote picked it for a reason and this was it. Google voshkod rocket tubes if you want this fellow. He also has a bigger brother costing more.

Sovteks new production
Very mid heavy tube with a dark top end without bite. Sounds heavenly on stuff that has female vocals that tend to be bright but overall not a very good tube.

Telefunken new production
These are produced by JJ and are not even close to the nos tubes. These tubes are very transparent top to bottom but a little thin and bright with a slightly recessed mid band. Good tube if you will combine it with a nos tube in the same circuit.

I'm currently using this with the nos telefunken as I didn't have the budget to go all nos. It's main strength is that it is very transparent and doesn't really have a strong signature to impose on any other tube in the circuit.

I'll update this thread if I test anymore tubes. Hope it's useful to those who have tube amps and want to experiment a bit.

I'm using the audionote oto Amp and with the Telefunken NOS in it, it is one of the most satisfying amplifiers that I have owned.

Please note that before tube rolling check with the manufacturer or on forums regarding what can and cant be rolled. If the amp runs the tubes hard then only the new production sovteks may work over a long period.

I just have one assembled pre-amp of Conrad Johnson PV-10 model. It has a 12AX7 & 12AT7 in the phono section, and 12AU7 in the line section. I am using Telefunken, ElectroHarmonix & RCA tubes, I must say that the ElectroHarmonix- Gold tubes are really good. I will post more on the RCAs and Telefunken in future. I use this pre with NAD power amp + Paradigm Studio Monitors. My source is a CA CDP, I also use Kenwood TT with Grado Blue MM Cartridge.
 

Kannan

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Location
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Very good thread for those graduating to tubes. Tubes are like OPamps and have their own flavors and fun to play around with.

Though I have stopped dabbling with tube gear some years back after finding satisfaction with SS, I recently had the opportunity to play with two 6J1 (EF95 family) based buffer, a basic Little Dot FX Audio Chinese one and another was the better built Yaqin SD-CD2.
I was then using Parasound DAC.

The Yaqin was superior to FX Audio. One primary reason being Yaqin is unity gain, and has no SS stage like the Little Dot which has a built-in SS gain stage with volume control.

The stock 6J1 tube that came with both the gadgets was crap. I then ordered various types of 6J1s which included Mullard, Voshkod (normal and gold tipped military grade), Philips and GE and borrowed Telefunken, Sylvania and an RCA from a friend who too purchased the buffers with me.

Without a grain of doubt, the Voshkods was the best to my ears. No roll off or suppression in the highs, no unnecessary bloat to the mids and the lows were to die for. The only caveat I found is it needs atleast 200 to 250 hours of break in and about 30 minutes of run from a cold state to even out. The Voshkods are for those who listen to all kinds of music

Mullards were the next best with the typical tube warmth to mids that many like, and a bit bloated lows (exaggerated. This was the typical of the tube breed to me and would possibly be preferred my most who like the typical tube sound.

The GE/Philips (565W version) have quite an airy presentation, but a little bit recessed on the lows, quite taut though, midrange is in-between Mullard and Voshkod, nice instrument separation. Probably attuned to persons who are more into Jazz kinda stuff but not for rock fans or fans of typical Indian recordings.

Rest of the tubes were ok bit nowhere near the ones mentioned above.
Ofcourse i will make a point here. The source signature and cable makes a big difference with buffers since there is solid state uo and down the chain.

After I upgraded Parasound to the Teac UD-301 Dual DAC, I no more found a need for a buffer, as I am more than happy with the pre-amp quality in the TEAC , where it uses two muses OP amps.

But since many are still using Little Dots in our forum, I felt sharing my experience.
However these Little Dots are great VFM gear for those who are using a very grainy chain, but again not with the stock tubes.

Cheers
Kannan
 

Kannan

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Messages
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Location
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I just have one assembled pre-amp of Conrad Johnson PV-10 model. It has a 12AX7 & 12AT7 in the phono section, and 12AU7 in the line section. I am using Telefunken, ElectroHarmonix & RCA tubes, I must say that the ElectroHarmonix- Gold tubes are really good. I will post more on the RCAs and Telefunken in future. I use this pre with NAD power amp + Paradigm Studio Monitors. My source is a CA CDP, I also use Kenwood TT with Grado Blue MM Cartridge.

Saar...Oru Audition???:)
 

Hari Iyer

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My tube amp uses these - 300B - Shaugaun (Chinese) for the Power, 12Au7 for the pre - Tungsol(Russian).
 

audiopro

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Jan 31, 2015
Messages
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Very good thread for those graduating to tubes. Tubes are like OPamps and have their own flavors and fun to play around with.

Though I have stopped dabbling with tube gear some years back after finding satisfaction with SS, I recently had the opportunity to play with two 6J1 (EF95 family) based buffer, a basic Little Dot FX Audio Chinese one and another was the better built Yaqin SD-CD2.
I was then using Parasound DAC.

The Yaqin was superior to FX Audio. One primary reason being Yaqin is unity gain, and has no SS stage like the Little Dot which has a built-in SS gain stage with volume control.

The stock 6J1 tube that came with both the gadgets was crap. I then ordered various types of 6J1s which included Mullard, Voshkod (normal and gold tipped military grade), Philips and GE and borrowed Telefunken, Sylvania and an RCA from a friend who too purchased the buffers with me.

Without a grain of doubt, the Voshkods was the best to my ears. No roll off or suppression in the highs, no unnecessary bloat to the mids and the lows were to die for. The only caveat I found is it needs atleast 200 to 250 hours of break in and about 30 minutes of run from a cold state to even out. The Voshkods are for those who listen to all kinds of music

Mullards were the next best with the typical tube warmth to mids that many like, and a bit bloated lows (exaggerated. This was the typical of the tube breed to me and would possibly be preferred my most who like the typical tube sound.

The GE/Philips (565W version) have quite an airy presentation, but a little bit recessed on the lows, quite taut though, midrange is in-between Mullard and Voshkod, nice instrument separation. Probably attuned to persons who are more into Jazz kinda stuff but not for rock fans or fans of typical Indian recordings.

Rest of the tubes were ok bit nowhere near the ones mentioned above.
Ofcourse i will make a point here. The source signature and cable makes a big difference with buffers since there is solid state uo and down the chain.

After I upgraded Parasound to the Teac UD-301 Dual DAC, I no more found a need for a buffer, as I am more than happy with the pre-amp quality in the TEAC , where it uses two muses OP amps.

But since many are still using Little Dots in our forum, I felt sharing my experience.
However these Little Dots are great VFM gear for those who are using a very grainy chain, but again not with the stock tubes.

Cheers
Kannan

Youre spot on with the Voshkods. Those Russians weren't fooling around.

Any experience using rca tubes?
 

Kannan

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The RCA I think was 5654, but not the black plate version which is supposed to be better.
This one is another tube that needs lots of break in.
Quite a good tube, It seems to throw a wide stage, highs were severely lacking. Midrange was nice, lows are its strength is what I would say.

I distinctly remember the massive stage it produced in 'Westminister's Choir' from the Chesky Records Album.
The intro of 'Radha Kaise Na Jale' was pretty disappointing as the highs were lacking big time.
 

bhaskarcan

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Don't have much experience with tubes, presently using BEL ecc83 and el84 in my amp. Previously have used Tele's, Philips, Siemens and Telam. Both driver and power stage. All of them are great sounding with different flavors. The amp originally came with Ge 5751 and Sovtek el84s.

Regards,
Bhaskar
 

yogibear

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Before I chime in my little experience with tube rolling, may I ask, how do you guys store or organize your tubes ?
 

Kannan

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how do you guys store or organize your tubes ?

I have a couple of unused NOS pairs of Voshkod 6J1s left with me. They are bubble wrapped and put inside a cardboard paper box individually and I have them stored inside a spare Tupperware box which is relatively airtight.
I did not understand the term 'Organize' though in your query.

Ofcourse do correct me if my storage method is incorrect.

Cheers
Kannan
 

yogibear

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Kannan, here I will get my little interesting secret out. My usage of terms, “ store, organize and even safe keeping and ready reckner” will become apparent. Please refer to the picture below:

7A4DDF9B-9C52-4146-8CD8-CC858B167514.jpeg

It shows an acrylic lipstick commercial display with graduated heights just like a stadium. I scratched my head when I started collecting tubes and had hard time keeping them safe and ready to refer to.

And this idea flashed. Each tube has a piece of foam at the bottom to secure pins and little on the sides for non-rattling, secure fit.

Can be done for smaller, medium size tubes and not “rich man” tubes like 2A3 or 300B. I have mostly 6J1P, EL84, AU7, AX7 and varaiations of them.
 
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