The 5E6P is the same as my 5E5P only with more or less military ambitions and with congenital “western” pins layout. It has more fragile specifications and more tight tolerance then 5E6P but it is the very same tube. There is very very very minor sonic difference between then and it is why I used 5E6P for my MF and tweeter channel. Still, the 5E6P and 5E5P has the same character in sound and might be consider as the same tube.

However, the 5E6P has the identical pins lowing with another my favorite tube – the 7721 or D3a in European specification:

http://www.goodsoundclub.com/pdf/7721_D3a.pdf

The 7721 is from the same family as my beloved 7788 and they were made in the truly golden age of tube manufacturing. It is a bit more powerful then 7788 and it is much better driver then 7788. The 7788 is a king for microphones and MC cartridges, the 7721 is a next output state…

Now is the fan…. The 7721 and 5E6P have the same pins and pretty much interchangeable.  The 7721 won’t handle as much power as 5E6P but my interest to use it on tweeters what I need no power.  I drive the 5E6P at 200V and a good 5E6P pushes 1800mS under 30mA and with minus 4V on bias. The 7721 (as a triode) give the same transconductance at the same voltage and 12mA on plate.

What I need to learn how would 7721 sound driving my tweeter.  I also need twice lower plate impudence for my tweeter driver (do not ask why - it is classified). The 7721 does has lower impedance but a higher current. I wonder what would be the 7721’s plate impedance at 12mA.

I wonder what would be the 7721’s plate impedance at 12mA

op.9, cv and the rest folks at the previous page.

After a long debate and consulting with multiple parties it looks like I am incline to go for nickel-iron alloy (Mu-metal) transformer in my substitution of single-stage MF amps with DHT. The objective it to drop the core “speed” and decrease plate loading. Let wee it is was a right direction to go.

Be careful to relieve me if I am not impressed, many promised no one excelled. :-)

Chris, I do not think that you will see me to think about transformers for other channels. I do not think that what I do will be some kind of resolution for Amorphous vs. Nickel transformers: in my care it will be a different amp with different out tube and differently loaded. The subject of faster core vs. more idle plate is very interesting but I am not the one to address it. I do want to do for a SLIGHTLY slower core, but not too much slower, then increase damping and power, will see where it will lead. I have a hunch the it might be a good direction for a limited bandwidth

About the transformer. I was thinking about it a lot. It will be 70% Nickel with limited inductance to support 200 cycles  at 50mA. 20:1. It will load the ~1250R plate of YO186 to ~6K. I have no idea if it will be good and if the YO186 even the tube that will give any interesting sound. Here is what I was thinking:

In my priory list are the “small” 4V DTH tubes like RE604, AD1, PX4 and those ghost-like YO186 since they were damped to my head and might be a “cheap” replacement of the imposable to get good RE604, AD1, PX4. If my project with small DHT will go south then I will go for full-size DTH but the high-impedance, like 10Y. Many experiences people advised me that I will not see in those high-impedance tubes the “tacky” and “overly romantic” qualities that I do not like in some DHT. I kind of would like to have “clean” and “neutral” sound, the one similar in “cleanness” to 6C33C, sine it will be DSET I do not see any problem with high OPT ratio. If the 10Y will not go as well then I will jump into the common 2A3/300B/45 wagon. If all falls then I will return to my ½ 6C33C… that it absolutely securest assurance of the result that I accept.

So, how to put one ass to all DHT transformers? I find a solution. In fact I did not find it, it just came itself. I spoke with Dave Slagle, inquiring what he can do and he told that his design implies the field interchangeable coils and adjustable gaps. That is a very cool solution for me. He also assured me that the assembling and disassembling of his transformer is Morons-complained, which is perfect for me. So, he will wind a base transformer and I might just get from him more windings if I need them.

Regarding you to hear the installment? Be my quest. From what you heard before my playback nowdays is 342 light miles ahead and I am very comfortable to play it "as is" without any MF modifications and with the Amorphous  magnetiks. I afraid that MF modifications will do some downtime foe a month or so, unless my unicorn YO186 hit the mark from a first try…

cv wrote:

…. I'm not sure I believe the overall hypothesis, I think it is more a function of the particular high/low impedance tubes he was writing about (300B, 10, 45 etc). But how this translates to neutrality above "levels 1 or 2" is another matter entirely...I think the 6C33 is a complete outlier in this respect.

cv wrote:

Yes, well - I wasn't really saying much; just a vague hypothesis. There is some tendency for lower Rp tubes, (and somewhat related) tubes with a certain harmonic structure, to sound more romantic, and hence impart that quality to music regardless of the content, the 6C33 has the lowest Rp out there, and is not the most linear, and yet you've found that somehow it manages to keep out of the way of the musical expression, or even enhance it in some ways? It seems to polarise tube fans - many won't touch it, saying it sounds solid-state... ie they are missing the romanticism (despite it being not that linear....) Something like a 10Y is rather clear/lean sounding *and* measures it too... so - along the lines of some of your comments  - what exactly is the 6C33 doing? I don't have that much experience with either tube, so these are just some wishy-washy thoughts... sorry I don't have more time to elaborate more clearly!

I have heard criticism of some people that 6C33 sound like solid-state and missing some romanticism. I disagree, not to mention that I practically never heard any good sounding amp around 6C33 – not because the tube but because the people who cooked the tube. The 6C33, with all appeared simplicity, is a difficult tube to get good sound out of it. In fact among all 6C33 amps that I ever heard in my view only ML2.0 was able to get right sound out of 6C33: the ML2.0 had no even references to SS or to tube sound. The SS vs. tube is for AA or DIYAudio.com - level of audio, the ML2.0 was beyond it…

Anyhow, I am not a huge fan of romanticism-addiction that some many DHT fans look like have. Romanticism is great but if music is not call upon romanticism then what would you do? I understand that those people who complain that 6C33C has “missing romanticism” understand neutrality in a different and very primitively way, so who care what they think. A two-year old child might have an Opinion why Moon is moving 2” further from Earch each year. Does anybody care what this child thinks?

I do not know what 10Y does – I never used it but from comments of people who have the similar to me detaste for the tubey “artificial melancholy” and pulled out-of-ass phony romanticism I concluded that 10Y MIGHT be different then the other DHT’s casual suspects. I do not know how accurate it is.

Anyhow, I kind of stuck with 6C33C and her definition of neutrality - I am quite comfortable with it. I begin to question my move toward to a single stage, but this is whole other subject. BTW, I do not know if you have seen it but David have made a transformer for my YO186:

http://www.goodsoundclub.com/GetPost.aspx?PostID=9689

I know you were interested.