The basically the same tubes. The 6E5P has own unit pins layout with heaters connected across the tube – very moronic in my view and it does not allow twisting the AC filament wires to the very end. The 6E6P has a common pins layout that most of western tubes of the same type use (D3a/7721and etc). The 6E5P is a bit larger and can dissipate heat better when you drive anode closer to 7W-8W.  They have different data in datasheet but it only because the 6E6P has more strict parameters and therefore on paper it provisioned for lower voltage, voltage power and shorter life. In reality is just because 6E6P the residual requirements for 6E6P were higher. The 6E5P considered consumer tube but 6E6P had a military version – the 6E6P-DR. Those tubes had ever more stringent requirements and the data on them was QA after the tube was burned out. Some of them had gold pit and so on. BTW, if you buy the DR tube then you will see that they even new look like they were used with darken glass – this is the result of pre-burring on factory.

Both the 6E6P and 6E5P need to be use in the same way – 200V on plate and no less then 15K on anode. Do not forget the grid sopped – they are very fast tubes.  Stonily they are very similar in my view with a very slight advantage of 6E6P in delicacy and softness. But it is VERY minor, near negligible. Among all 6E6P and 6E5P that I had I have seen only one that was microphonic.  Be advised that those tubes tine pick up some HF nose as they age and become worn. Also be advised that both 6E6P and 6E5P are noise what they cold. As the heat up they shall become calm and silent, usually it takes 5 minutes. I do not know what you mean “respond differently regarding vibration” are you heating them with baseball bat and mount them on a top of  the Vibratex Rabbit Habit Vibrator?

Romy the Cat wrote:

Stonily they are very similar in my view with a very slight advantage of 6E6P in delicacy and softness. I do not know what you mean “respond differently regarding vibration.”

Romy the Cat wrote:

Floobydust, I have a question to ask. Those dam Ruskies when they did the YO186 then made it to have an absolutely idiotic pin layout. The layout is very simile to 2A3 but one of the pins a few mm away, far enough for me to consider that it would  not be save to bend the pins. So, what I heard is that in 30-40 Germans made the similar pins and I wonder if any tubes sockets for them are available? I told that there is a Germany aftermarket company that make those add sockets very recently. So, since you are in Germany, or any other Germans – did anybody see the “faulty” not-fitting 2A3 tube sockets? It is not imposable to accommodate some other solution to YO186 but I would prefer to buy off the shelf socket and do not be bothered with it. Ich bin Katze

drdna wrote:

As I had been looking at all these tubes I began to also inspect their interior construction. This will amuse you: one thing I would do is to hold the tube right up to my ear so the glass would be touching and thus mostly damped. Then tapping the tube slightly would cause the internal cathode and anode to vibrate a bit, making a noise. There was a correlation between the type of noise and the sound the tubes in the stereo would make when music was played.

Years back what I used Lamm LP2 phonostage with notoriously microphonic 417A tubes I was doing something similar by maxing out volume, sticking the head into the horn and hitting the tubes with a little hammer with rubber coating. I was under impression that the character of noise and the decay of the nose would symbolize how good the tube was. Well, it did and did not. It helps to filter out the obviously bad tube but if does not helped to predicts how it might sound. Pay attention BTW that my methods was using hot tubes, not the cold tubes. If you feel that you are able to get the correlation between the type of noise and the sound then it is fine but I feel that it is more contrived self-convincing. I do clear remember the I had some tubes that did not have the lower noise (they were passable though) but they sounded the best. I think this method is OK to filter out the tubes of the same make (brand, type, vintage) but I think it is worthies if you try to compare the resonating noise of the tubes that have even slight construction differences.

drdna wrote:

I don't have a circuit built now for the 6E5P, but I have a bunch of 6E5P & 6E6P tubes. Based on my examining them I was guessing that the 6E6P should have slightly more "clean & neutral" sound than the 6E5P. I was curious if this was the case, so I thought to ask you, since you have a familiarity with both tubes.

You can make what I did. I made a small adapter that cross wires and convert 6E5P into 6E6P. Then you can plug in your tube socket whatever tube you wish. BTW, the 6E5P and 6E6P have in a way a unique construction that has a lot of to do with the way how Russians shaped in this tube the profile of electron cloud. The 6E5P and 6E6P were reportedly made to completely eliminate the Dynatron effect. I do not know or they did or not but the spaces in there are atypically huge, it is a fact. I have no idea how all this affect sound but I like how it sounds. Plug it in and you will hear it yourself.

Romy the Cat wrote:

drdna wrote: As I had been looking at all these tubes I began to also inspect their interior construction. This will amuse you: one thing I would do is to hold the tube right up to my ear so the glass would be touching and thus mostly damped. Then tapping the tube slightly would cause the internal cathode and anode to vibrate a bit, making a noise. There was a correlation between the type of noise and the sound the tubes in the stereo would make when music was played. If you feel that you are able to get the correlation between the type of noise and the sound then it is fine but I feel that it is more contrived self-convincing.

Romy the Cat wrote:

When I said four transformers I meant that I can see 4 type of the tubes. The 2A3 with 700-80R on plate, YO186 with 1200R on plate, the 45 with 1800R on plate and 10Y with 5K on plate. Hey are requires different transformers.  I do not like taps. I like to have transformer with remapable sections. The 2A3, 45 and YO186 still might be possible to care with one transformer; the 10Y would need a very different beast. Also, I have a filing this time to try something different. I might go with DHT for a slower core OPT but to load anodes more idle – I have a feeling that it might bring me where I would like to be. I am thinking about 4.5K-5K for 2A3 – I mean a lot of impedance, as much as my S2 will be able to handle. I even will to give up a bit speed of my code for trying it…. In my single-stage IDHT amp I have no gain to afore this luxury.

Studying YO186 I concluded that that it was not AD1-type tube as it was mistakably considered but it rather was an equivalent for RE604, LK460 , E406 , KL71403, K435/10, P460, P4, O15/400, RE614, U4H

They all 4V with near 1A on filament. They all from one to two kohm on plates (with exception of U4H that has 4K), basically 1.3-1.4K in average. The YO186 with it 1.2K would feet the bit but the plate impedance would greatly vary with operational current anyhow.  They all have gain of 2-3-4. And the YO186 is right there. The all have 30-40 on grid and semi-identical size with YO186 with YO186 being a bit larger. The all 10-12W on plate with YO186 15W but I think here is where the YO186’s larger balloon is in advantage. So, I think the YO186 with RE604/KL71403 have found its family.

Looking at the externals construction of Telefunken RE604 and Klangfilm KL71403 I kind of surpassed that YO186 is made better or I would say more refined. It would serially say nothing about sound or about the quality of materials were used. I was not able to found anybody who used RE604 and YO186 or KL71403 and YO186, so I have no idea how one stand against other. As one guys said to me: “Romy do not search anyone - you are the person to answer this question.” Perhaps I am, as there are very few YO186 users out there. I would be very interested to see how the RE604/KL71403/YO186 class tube would push against the 2A3/45/6A3 class and the 300B class.  Of course there is a great variety of differences between the different between of the same DHT tube, but still it is interesting to know if any common tendencies are there. it is very much might be that there is no important differences in any of it and it will all depends from how good the given tube was made. I plan in future to buy one RE604 and one KL71403 to see were the YO186 stands (as I have life supply of YO186) but first I need to found out the answer for the main question: how much S2 driver in context of Macondo will b e able to endure the YO186’s loading.

People out there usually load RE604/KL71403 to 3.5-4K getting from RE604/KL71403 1.5-1.8W. That might be a good start for YO186 if I run it at 57mA but sine I will be running my YO186 with no bass then something suggests me that I might end up with lover currant, higher plate impedance and might load YO186 to 7-12K. The “sucks” part in all of it that it is difficult to found out what I need without actually falling in something and recognizing of with what I do not need…

Each new idea is an opportunity or a pain to be involved into a new round of custom work. With all my considerations regarding engaging the DHT I more and more biased to have YO186 as the leading candidate, in fact I almost decided to do it.  From a certain perspective the YO186 is Russian-made RE604 that is good itself, considering the mythical quality of sound from RE604 but there is a twist in it. If the YO186 was mane in 1947 then I would say “Yes”, Russians copy the RE604. BUT, first the YO186 looks like none of the Telefunken or Klangfilm tube of the period and second the YO186 came to production in 1932 and this make the story VERY interesting.

The Russia of very beginning of 1930s is an interesting time. The generation old empire engineers among those who do not escape to west or was not killed still were around and it is very possible that Telefunken stolen RE604 from Russians, or at least that they were independent developments.  A commercial public radio was introduced in Germany in 1923 and in Russia in 1926. So, Russian in beginning of 1930s had people and recourses to do the interesting things and they did.  So, the YO186 might be an interesting tube on it’s own.

Anyhow, returning back to the pain of new round of custom works. It looks like I would need another low inductance output transformer 20:1 or even perhaps 5 more.  This sucker needs to be ordered but I kind of debating what I want this time. I have two options: to go for fasters core (amorphous) as I did before and load the tube a bit harder or to go for more mellow core (cobalt, nickel, Mu-Metal, chicken, wood etc) but to let the plate to idea a bit more. With 350V and 30mA I will get around 3W from YO186 – much more then I need, so I can but some power on damping, thankful the gain won’t be an issue with two stages anymore.  The question is how much S2 driver will be able to handle – I have no idea until I try…

Since I kind of targeted with my YoYo tube to the RE604-class then I am considering to pay once a lot of money and to buy one of those RE604 to see how much YO186 better or worse. (BTW, do not be under impression that YO186 is cheap – it is not still it is not $1500 per NOS RE604). Standing the park of small oxide power tubes from 30 it look like there is a great variety of the tubes that that I might be using in the amp above if I go for YO186.

Besides the mentioned Telefunken RE604 and Klangfilm/Siemens KL71403 it also might be Philips RE-614, Valvo LK460,  Triotron k435/10, Mazda 601 or DW302, Mullard AC084, Ferranti P4, Tungsram P460 or O15/400 ( the last has slightly higher plate impedance) and Marconi PX4.

The similarly of YO186 with PX4 opens a whole new chapter in exploration of YO186. I think I did heard an amp once with some kind of yellow driver but I did not paid attention to it’s sound.  During that times all of those DIY amps I considered as people soldered instead of sniffing bangs. I was too far from truth as the owner of the amps was “dead”, still it would listed that amp now just for sake if my curiosity in PX4.

Interesting that Prague-based company KR Electronics that Adrian pitched above makes today production of PX4

http://www.kraudio.cz/pic/px4.jpg

That kind if make my idea of going for RE604-YO186-class tubes kind of expendable and not so dead-end bookish if the YO186 heat the wall sonically. I was trying to found out how much KRs’ PX4 cost but it looks like no dealers have them. Are any visitors on my site from Czechoslovakia who can quote the KRs’ PX4 price? As anyone around Boston who run PX4 and would be interested in temp PX4/YO186 swapping for few days?

Romy the Cat wrote:

Those dam Ruskies when they did the YO186 then made it to have an absolutely idiotic pin layout. The layout is very simile to 2A3 but one of the pins a few mm away, far enough for me to consider that it would  not be save to bend the pins. So, what I heard is that in 30-40 Germans made the similar pins and I wonder if any tubes sockets for them are available? I told that there is a Germany aftermarket company that make those add sockets very recently. So, since you are in Germany, or any other Germans – did anybody see the “faulty” not-fitting 2A3 tube sockets? It is not imposable to accommodate some other solution to YO186 but I would prefer to buy off the shelf socket and do not be bothered with it.

I never used any of them but it is not a big deal to found them, even Chinese nowadays make a tone of them, the “gold” plated.

KM,

Yes, it turned out that the B4/B5 sockets are not a problem at all. I do not like the original sockets with springy contacts and I like the contemporary sockets that hold the pins with full micro-tubes.

Regarding the YO186’s price - this is difficult. There is no price form them as there is no market for them, they just not available for sale. There are some prices perhaps in Russia but considering that they have just a few of them change hands per years then the prices might be whatever asked. The reason why I got them because I came across a party of 10 tubes. I would not buy 2 or 4 of YO186 as I would never find more if I like then and need them more but I figured out the 10 of them might be a life-long supply. I will not incriminate myself by saying how much I paid for them – it was more then might be considered sane. I just will say that it was comparable to the prices of the period 2A3, but still lover then it would be for a brand new RE-604.

It is only if you chose to employ tube rectification.  Many people claim that tube rectification affects sound greatly in this or that way and they are right, it does. However, it does only because the circuit is designed to be affected by rectification. Let see what we have in case of tube rectification. Uselessly after the rectifier we have a small cap to ground then in best case a choke and another small cap. In better case we have another few CL or RC chains. The rectifiers can’t handle fast inrush of current to charge big caps. To put time delays is expensive, so most of the tube amps end up with 20-100uF anode cap. The ripples looks like more or less killed, and AC coming from tube look like has some path to ground.  However, the capacitance of the last cap before anode is small and cap does not act as brick wall, shunting all AC right the way to ground, letting the AC voltage from plate to “see” choke and to see the rectifier tube. Sure, in this case the sonic characteristics of choke and rectifier maters.

Look what I do. I use SS rectification and invariably input choke filter with additional RC chain. The key in here is to use the last cap of a large value that would decouple the PS from AC voltage. This way rectification is less irrelevant and I did a bunch of the tests to confirm it. In fact I found that tube rectification had lighter lower frequency harmonics that I did not like.

I can give you an interesting test to look into it yourself. Take you normal tube rectified SET mono-blocks (A and B). Drive A amp normally but B amp connect in a kinky way. You need to power the driver stage off the B amp from the last cap of the A amp’s power supply. Then feed the A amp with signal but listen not the A amp but the result of penetration of AC voltage unto the B amp. Diving the last cap on the A amp down you will make the AC voltage from plate of A amp to find ground deeper into A amp’s choke and rectifier.  The further ground is the better sound you will hear via the B amp. Your objective shall be to have the worst sound from B amps, or in the best case absolute silence from it. In this case the A amp will be indifferent to anything behind the last cap. I made those experiments and … I do not listen the sound of rectifiers. I do not say that it is imposable to make good sounding amp with PS elements being “in AC path”. I just try do not do it…

This post is a continuation of my late desiccation with Chris from:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=9641

David Slagle have made the OPT for YO186

http://www.intactaudio.com/forum/viewtopic.php?p=3560

Ideally I would like to try in their 20:1, 25:1 and even 30:1, loading the output tube less and less and to see how S2 driver will behave. David does not do re-mapable secondaryies but he does replaceable coils, so it might be still coming. Still, I think 20:1 might be a good place to start. The inner-stage will be transformer will be 70% nickel, 20% of chocolate, 5% of rose’s smell and 5% of penicillin. Go figure how it all will work together. Theoretically this transformer "as is” would allow to drive any 2A3/45 type of tube in a good “unloaded plate” mode.  Let see where this fly will lend. The inner-stage transformer will be here in 2 weeks and then I am planning to start destroying my Sun Audio kit with 6E5P-2A3 and to experiment with my new version of DHT Milq before I apply the changed (if they were worthy) to the 6ch Melquiades DSET.

drdna wrote:

However, there is no comparison to the expensive tubes from Kron, Sophia, and Emission Labs. These are all in a separate category. These produce a very different sound. It is like this: on the old black and white TV sets, there were controls for brightness and contrast. The NOS Sylvania tube has the controls set quite well, but it is a totally different ballgame from a new color TV. Now, some movies, like Citizen Kane, depend on black and white. It would not work in color. Likewise, the NOS tubes present the music in a unique way the new tubes do not.

This comment of your about “some movies” makes developed nerviness in me.  What in your view in the Kron, Sophia, and Emission tube would not allow them to operate in monochrome setting? Are they so saturated with color that they toss them where they shell not? I do not want to be completely taken away by your association but am a bit concern the you still give some black/white credit to NOS Sylvania. Can you more elaborate on it? Where is from you view is the place where the NOS Sylvania still hold the ground?

Romy the Cat wrote:

<P>  drdna wrote: However, there is no comparison to the expensive tubes from Kron, Sophia, and Emission Labs. These are all in a separate category. These produce a very different sound. It is like this: on the old black and white TV sets, there were controls for brightness and contrast. The NOS Sylvania tube has the controls set quite well, but it is a totally different ballgame from a new color TV. Now, some movies, like Citizen Kane, depend on black and white. It would not work in color. Likewise, the NOS tubes present the music in a unique way the new tubes do not. </P> <P>This comment of your about “some movies” makes developed nerviness in me.&nbsp; What in your view in the Kron, Sophia, and Emission tube would not allow them to operate in monochrome setting? Are they so saturated with color that they toss them where they shell not? I do not want to be completely taken away by your association but am a bit concern the you still give some black/white credit to NOS Sylvania. Can you more elaborate on it? Where is from you view is the place where the NOS Sylvania still hold the ground?</P>The Cat