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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Western Electric New 300B made in USA 2018

It is not very easy to resurrect 80 years old manufacturing process. Many materials simply cannot be found, because there was no demand for them for decades. Some material and processes cannot be used, because modern standard on safety and environmental conditions prohibit you from using them (does RoHS rings the bell for you). That means some materials and processes need to be altered, and that may result in final product being worse than it used to be 50 years ago. And all these when you need to compete with Chinese manufacturing that runs full steam, has less environmental restrictions, and the only advantage you have is QUALITY.


This reminds me boutique phono cartridge manufacturers in Japan. Many of them are in fact ONE MAN shop. They do make nice niche, very expensive low volume products and often you have to wait while ordered item is manufactured after you paid for it.


To be honest, most often people buy those tubes because of the brand name and the absolute focus on quality that kept the former Western Electric company being the supply for military and federal equipment. They just wanted to produce the best.


Myself I'm using such ONE Man shop parts in my system beside other MIL parts. Its the best system I've ever had, nearly totally DIY and build with parts that lasted a lifetime and everything bullet proof quality and I've to tell you, the nitro laquer on my 1971 Mercedes W115 was the best quality of all. Thick and deep shining creamy white nitro. Not comparable with todays water based car laquer, but unfortunate its against environment laws today for the motor car companies to use it still. And thats the same as with electron tube manufacturing today.
 
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there can be a self-defeating aspect too. If you make tubes that last forever then once everyone who's crazy enough to pay the steep price has bought their tubes the demand will collapse and the company goes out of business again. Look at JJ, they make tubes for guitar amps, they get burned up fast and they get to sell more tubes. As a result, JJ will be around for a long time and we'll be able to buy their really good 300B's long after WE....

well it's just a perspective, hopefully we'll see the opposite, WE will prosper and they will see demand increase over time so they can reinvest and produce other tubes, widening their product range to compete.
 
As to bad-mouthing JJ tubes . . .

1. Over the decades, JJ has constantly improved their tubes.
Reliability, consistency of characteristics, etc.

2. Eurotubes.com in the US re-tests all the tubes they get from JJ in Slovakia.
They have lots of tests, not just Gm, u, rp, noise, and other characteristics too.
They do not have years-old tubes lying on the shelves; the tubes are fresh production.

3. Many Guitar Amps abuse and exceed one or more of the maximum specifications of the tube. Exceeding 2, 3, or even more maximum specs can cause premature tube failure.
Surprise!
This has been going on for decades.
It is these Abusive amplifiers that will be around for decades more, constantly destroying good tubes!

Your mileage may vary.
 
Some decades ago, when the east european 300B clones popped up on the market I had the opportunity to compare one of those czech valves with an original set of WE 300B (not Whitener 300B). Those clones had its "improvements" over the original tubes, for e. g. more lower frequency energy, but it had nothing in common regarding its sound character with the original Western tubes. Just like a fake Rolex had nothing in common with the original but the housing and the name. It was the same sonic difference than comparing an EL34 vs. a 6550. Totally different tubes and sounds. This is a very interesting topic, because the data curves of both tubes were equal or at least nearly the same but the sound character wasn't. This may have changed or not but since this time I don't believe in fake Rolex.
 
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As to bad-mouthing JJ tubes . . .

I hope you didn't think my reference to JJ was in any way negative. My comment was intended to say that Guitar Amps by reputation abuse tubes by operating them hot which therefore wears them out faster than they would if used in a hi-fi amp. You have said the same thing as I was trying to say but with too few words to avoid ambiguity. I believe JJ tubes make a very good product and hence I bought their 2A3-40.
 
Fixed Bias (or Adjustable Fixed Bias):
EL34 max Rg 500k
6550 max Rg 50k
Caution: Red Plate danger when Rg is too large

One is a True Pentode, with a real Suppressor Grid.
One is a Beam Power Tube, with Beam Formers.

For most amplifier designs:
Tube Rolling a 6550 into an EL34 amplifier . . .
Just Plug and PRAY
It is not a case of Plug and Play

On a high powered push pull amp, I have seen individual 10 Ohm cathode resistors burned to a crisp when 6550s were inserted into the EL34 sockets, even though the fixed bias was adjusted to the same current. Set the fixed bias level for specified current, then just wait until later when the 6550 starts to run-away.

And I saw a 6550 Red-Plate that was put in a SE EL34 Amp, and re-biased for the same current.

Those two tube types will sound different in the same amplifier at low level power and mid level power . . .
Unless there are Large amounts of negative feedback.
And one single amplifier will not be optimized for max power for both tube types, so that will sound different too.
If it does not sound different, I want to hear that amp.
 
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Fixed Bias (or Adjustable Fixed Bias):
EL34 max Rg 500k
6550 max Rg 50k
Caution: Red Plate danger when Rg is too large

One is a True Pentode, with a real Suppressor Grid.
One is a Beam Power Tube, with Beam Formers.

For most amplifier designs:
Tube Rolling a 6550 into an EL34 amplifier . . .
Just Plug and PRAY
It is not a case of Plug and Play

On a high powered push pull amp, I have seen individual 10 Ohm cathode resistors burned to a crisp when 6550s were inserted into the EL34 sockets, even though the fixed bias was adjusted to the same current. Set the fixed bias level for specified current, then just wait until later when the 6550 starts to run-away.

And I saw a 6550 Red-Plate that was put in a SE EL34 Amp, and re-biased for the same current.

Those two tube types will sound different in the same amplifier at low level power and mid level power . . .
Unless there are Large amounts of negative feedback.
And one single amplifier will not be optimized for max power for both tube types, so that will sound different too.
If it does not sound different, I want to hear that amp.


Sorry to be misunderstood. I didn't meant to have compared both tubes in the same amp. I know that they are different, technically and sonically.
What I tried to describe was that 300B tubes could have the same sonic difference than both EL34 and 6550 heard in two different amps (that were each designed and optimized for one tube, no tube rolling being applied here). Having known those sonic differences and preferring an output pentode, it was time for me to DIY my own pentode SEP amp which is serving me fully satisfacory in terms of its sonic footprint. No triode amp any longer needed.
 
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Schmitz77,

I am glad you have an amplifier you are enjoying listening to.

SEP?
Single Ended Pentode?

I did not mean to criticize.

There are so many varied experiences in tube amps.
And a vary large portion of them are pleasing to those who own those widely varying amplifiers.

In amplifiers that I have made:
I have used 45, 2A3, 6B4G, 6A3, 300B, 6BX7, and 6CK4.
I have used EL84, EL34, 6550, KT66, KT77, KT88, 6V6, 807, 6L6, and 7591.
Some have been single ended, some self inverting push pull, and some push pull.
Some have had no negative feedback, local negative feedback, and global negative feedback.
Pentodes and Beam Power Tubes have been in Pentode/Beam mode, Ultra Linear mode, and Triode wired mode.

And I still have lots to try.

I do enjoy listening to music playback using tube amps.
 
High output impedance for a pentode? This is all relative and adjustable. The pentode has a slightly higher impedance but for a given output transformer, the circuit defines with its parameters the output impedance and that has to fit the output transformer. And yes, its using negative feedback to stabilize the amp. Will it sound like a trioded- pentode therefore? Nope.
 
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Fixed Bias (or Adjustable Fixed Bias):
EL34 max Rg 500k
6550 max Rg 50k
Caution: Red Plate danger when Rg is too large

One is a True Pentode, with a real Suppressor Grid.
One is a Beam Power Tube, with Beam Formers.

For most amplifier designs:
Tube Rolling a 6550 into an EL34 amplifier . . .
Just Plug and PRAY
It is not a case of Plug and Play

On a high powered push pull amp, I have seen individual 10 Ohm cathode resistors burned to a crisp when 6550s were inserted into the EL34 sockets, even though the fixed bias was adjusted to the same current. Set the fixed bias level for specified current, then just wait until later when the 6550 starts to run-away.

And I saw a 6550 Red-Plate that was put in a SE EL34 Amp, and re-biased for the same current.

Those two tube types will sound different in the same amplifier at low level power and mid level power . . .
Unless there are Large amounts of negative feedback.
And one single amplifier will not be optimized for max power for both tube types, so that will sound different too.
If it does not sound different, I want to hear that amp.


6550 is much closer to KT88 than to EL34. But 6550 is more rugged than modern KT88, thus from reliable operation perspective KT90 will be more appropriate replacement.
 
Schmitz77,

I am glad you have an amplifier you are enjoying listening to.

SEP?
Single Ended Pentode?

I did not mean to criticize.

There are so many varied experiences in tube amps.
And a vary large portion of them are pleasing to those who own those widely varying amplifiers.

In amplifiers that I have made:
I have used 45, 2A3, 6B4G, 6A3, 300B, 6BX7, and 6CK4.
I have used EL84, EL34, 6550, KT66, KT77, KT88, 6V6, 807, 6L6, and 7591.
Some have been single ended, some self inverting push pull, and some push pull.
Some have had no negative feedback, local negative feedback, and global negative feedback.
Pentodes and Beam Power Tubes have been in Pentode/Beam mode, Ultra Linear mode, and Triode wired mode.

And I still have lots to try.

I do enjoy listening to music playback using tube amps.


In fact its a tetrode but it acts like a pentode, so it could be called single ended pentode amp.
For me, its more important to have a valuable design and parts than to make a cult of a single output tube. And it means freedom to have learned to build amps that could be special designed to bring the best out of any type of output tube. Saves budget money, too. Because that savings being invested in parts for the amp could bring a much bigger benefit in terms of sound than a cheap designed WE amp could ever do. So for me, I'd love to do an amp with an original WE 300B but that should be a cost no object project these days and not a budget amp. Then it would be fun. Otherwise the amp would have a hard time competing with other amps. And yes, lots to try and hear still.
 
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High output impedance for a pentode? This is all relative and adjustable. The pentode has a slightly higher impedance but for a given output transformer, the circuit defines with its parameters the output impedance and that has to fit the output transformer. And yes, its using negative feedback to stabilize the amp. Will it sound like a trioded- pentode therefore? Nope.

interesting

I have seen some glowing reviews of the Shindo Cortese, an amp using a Siemens f2a pentode output with feedback and if these tubes were not at stupid prices I would be tempted to clone it. The stupid prices also resulted in the manufacturer changing to a 300b output tube, same topology but a lower feedback factor. There are very few comparison reports but some preferred the 300b. Well, I may make a clone of that instead using an 845 as I have a pair of those but no 300b’s. I think it's v difficult to compare pentode with triode without keeping the same topology.

I built a spud amp (‘Yukon Gold’) with a pentode output (and input :D) and found the pure pentode without feedback too odd sounding but it worked best with some feedback although not fully triode wired. It started out as a clone of the Jeff Larson spud amp (readily reverse engineered) of some fame but the sound was not right without these changes.

One day, after I’ve built my 2a3, 845, 47 and others, I may have to build a 300b just because it seems odd to be a tube amp builder and not to have used the most famous one of all and when I do I will take a look at the state of production and reviews for new production WE as an option.
 
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Bigun, the data of both F2A and 300B are so different (not in its output impedance, but otherwise) than the conclusion could only be both amps are using different circuits. And thats what they do but in the end, each is optimized for the choosen output tube.
And thats makes them comparable. Its not that you could do tube rolling on the same amp, but same amps with different circuits. And thats how it should be done to let every tube shine in its most magical ways.
Did build a 300B amp already but it wasn't that much refined to let the tube shine. It just was a good amp, although it kicked some others out. Today, I would do it quite different and because of the high prices real 300B command, this project should better be determined a cost no object one. Its like flying to the moon and you better succeed otherwise too much wasted money for a just mediocre amp.
 
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