[bcowen]

In my best Mr. T voice...I pity the fool who nicks a wire inside my tester and causes a short!

Oh, and in the manual I love the section on how to prevent it from falling into enemy hands in case an expeditious retreat is necessary.

If you print out the Maintenance Manual, the resulting stack of paper is almost as big as the tester.

https://bama.edebris.com/download/military/tv7/TM 11-6625-274-35 hi res.pdf

 

[Novik tube]

I want to buy a used Valhalla
Tubes are not needed! Better than European version, but I can also consider American
Age and condition is not very important! I welcome any advice and suggestions.

 

[Runrunsmithfly]

The inexpensive JJ 6922 tubes continue to impress me. I have Amperex orange globes that cost more but the JJ's are more dynamic and provide a sound that I like.

 

[GumbyDammit223]

If you print out the Maintenance Manual, the resulting stack of paper is almost as big as the tester.

https://bama.edebris.com/download/military/tv7/TM 11-6625-274-35 hi res.pdf

I do love finding PDF'd manuals online for free. The problem is that a lot of them are the result of being run through a document feeder at high speed and the quality is usually somewhat lacking. I almost do a little dance when I find one that has been scanned at something approaching normal print resolution. And if I find one with pictures that are more than a black splotch, I do do a little dance!

 

[Novik tube]

Hello!
I have been using Soviet tubes for more than 40 years and I want to share some of my comments.
6N6P began to be produced in 1956-57 in Fryazino. Pairs from these years are very rare and I saw an listings on the US market for over $1000 a pair.
Since 1962, they began to be made in Tashkent at the PHOTON plant.
In 1965-1966, NEVZ began to make the same model of tubes.
A lot of different parts of the same model before 85 differ in construction and therefore (probably) can have a different sound (not explored so far)
All these modifications had a filament current of 0.75 A (as I understand it, Valhalla is designed for it)
And if the filament current of these tubes is powered separately, it is clear why the Schiit does not recommend using 6N6P-IR (0.9 A) and most importantly 6N6P-DR (0.85 A)
which in other respects correspond to 6n6p
I had to change 6N6P to 7044 with a converter for the owner of an expensive phono stage and he really liked it
I am carefully studying this thread and have only read half of it so far (about 6 years), but I have already seen a request to replace 6N6P several times
I want to collect more information on this subject and will try to post it on this thread! Maybe this will help someone!
An example with 6N23P-75 Reflector (NG) is not the only possible one, as it seems to me now.

I want to add a little and clarify the first message a little!
I hope this can help you spend your money more carefully when buying 6N6P
1957-1959 Fryazino box anode is the most expensive and good sounding
1959-1964(65?)!!!! Photon Tashkent up to 62 years old is also a box anode, but with a different getter - also good and expensive (but cheaper than Fryazino)
after 62 wings! (up to 64-65?) is much cheaper.
Everything that is called a photon after 65 was done in Saratov (reflector-PUL) with a similar (but different) technology, it is even cheaper
Somewhere from 67-68 they started doing it at NEVZ in Novosibirsk
If possible, I will post a photo and more additional options!

 

[greenblured]

Look out for the miltary specification mark when shopping for 6n6p's. It consists of two digits, followed by a diamond/rhombus shape, and then a final digit.The first two digits indicate the military specification number, while the final digit indicates the year in whitch the tube was tested and approved.
Tubes with the military spec. marks sounds better than the ones without (of same type and vintage). Red tip or OTK number is not relevant in regards to sound quality IME.
Make sure to get properly tested and matched pairs.It matters a lot IME. Some of untested pairs of old Foton's i bought were microphonic, noisy or had a channel imbalance.

 

[Novik tube]

The unbelievable cost of 6N6P made me delve into this topic as deeply as possible.
Thanks in advance to those who can either supplement or refute what I will state.
In 1956-57, a new (having no direct analogues) 6N6P tube was developed in Fryazino. In those years, it was a research institute and plant.
This partly explains the very low quality of commercially produced tubes at that time and the huge percentage of rejects that can now be on the market. This does not negate the excellent sound quality that was discovered many years later.
This tube was designed for completely different purposes. From 1960 to 1964-65, technology and production were transferred to Tashkent to the Foton plant and there they immediately changed the getter and installed a box-shaped anode until 1962 (with minor changes)
From the middle of (approximately) 1962, another form of anode (winglets) began to be used, which was subsequently used in all subsequent versions and in other plants too!

In the middle of 1965, the Foton plant (Tashkent) stopped the production of vacuum tubes (this is official information). Therefore, everything that was released later has nothing to do with it.

In a comment to a post from Greenblured :

All stamps that are applied to the tubes, except for the model name and year of manufacture, refer only to the quality control system. Sometimes there can be three or four of them, and also red and yellow dots on top of the lamp, which mean input control at the enterprise that received (bought) these tubes for its products!

The design and, accordingly, the sound, these icons did not determine!

 

[bcowen]

The unbelievable cost of 6N6P made me delve into this topic as deeply as possible.
Thanks in advance to those who can either supplement or refute what I will state.
In 1956-57, a new (having no direct analogues) 6N6P tube was developed in Fryazino. In those years, it was a research institute and plant.
This partly explains the very low quality of commercially produced tubes at that time and the huge percentage of rejects that can now be on the market. This does not negate the excellent sound quality that was discovered many years later.
This tube was designed for completely different purposes. From 1960 to 1964-65, technology and production were transferred to Tashkent to the Foton plant and there they immediately changed the getter and installed a box-shaped anode until 1962 (with minor changes)
From the middle of (approximately) 1962, another form of anode (winglets) began to be used, which was subsequently used in all subsequent versions and in other plants too!

In the middle of 1965, the Foton plant (Tashkent) stopped the production of vacuum tubes (this is official information). Therefore, everything that was released later has nothing to do with it.

In a comment to a post from Greenblured :

All stamps that are applied to the tubes, except for the model name and year of manufacture, refer only to the quality control system. Sometimes there can be three or four of them, and also red and yellow dots on top of the lamp, which mean input control at the enterprise that received (bought) these tubes for its products!

The design and, accordingly, the sound, these icons did not determine!

This is great info. Thanks for sharing!

 

[GumbyDammit223]

The unbelievable cost of 6N6P made me delve into this topic as deeply as possible.
Thanks in advance to those who can either supplement or refute what I will state.
In 1956-57, a new (having no direct analogues) 6N6P tube was developed in Fryazino. In those years, it was a research institute and plant.
This partly explains the very low quality of commercially produced tubes at that time and the huge percentage of rejects that can now be on the market. This does not negate the excellent sound quality that was discovered many years later.
This tube was designed for completely different purposes. From 1960 to 1964-65, technology and production were transferred to Tashkent to the Foton plant and there they immediately changed the getter and installed a box-shaped anode until 1962 (with minor changes)
From the middle of (approximately) 1962, another form of anode (winglets) began to be used, which was subsequently used in all subsequent versions and in other plants too!

In the middle of 1965, the Foton plant (Tashkent) stopped the production of vacuum tubes (this is official information). Therefore, everything that was released later has nothing to do with it.

In a comment to a post from Greenblured :

All stamps that are applied to the tubes, except for the model name and year of manufacture, refer only to the quality control system. Sometimes there can be three or four of them, and also red and yellow dots on top of the lamp, which mean input control at the enterprise that received (bought) these tubes for its products!

The design and, accordingly, the sound, these icons did not determine!

Looking a bit into this, I see that ECC99's come up as a potential cross. If I compare the pinouts, I see that the 6n6p heaters are in parallel across pins 4 & 5 with a screen/shield connected to pin 9. The ECC99 on the other hand has the heaters in series across pins 4 & 5 with pin 9 as a center tap on the heaters. In my mind those are not directly swappable. Am I wrong here? Mind you, I'm not even looking at numbers yet.

The reason I'm asking is that I'm trying to come up with settings for my TV-7 tester to test them. @bcowen have you found anything comparable with your tester(s) to test what you have?

 

[bcowen]

Looking a bit into this, I see that ECC99's come up as a potential cross. If I compare the pinouts, I see that the 6n6p heaters are in parallel across pins 4 & 5 with a screen/shield connected to pin 9. The ECC99 on the other hand has the heaters in series across pins 4 & 5 with pin 9 as a center tap on the heaters. In my mind those are not directly swappable. Am I wrong here? Mind you, I'm not even looking at numbers yet.

The reason I'm asking is that I'm trying to come up with settings for my TV-7 tester to test them. @bcowen have you found anything comparable with your tester(s) to test what you have?

I have the settings written in my 752A manual, but I honestly can't remember where I got them. Probably on a forum somewhere, but damn...old age and memory don't go well together. If you can't find anything with a search, might be easiest to make an adapter and use the ECC99 (or E182CC) settings if one of those is in your TV-7 chart.

 

[GumbyDammit223]

I have the settings written in my 752A manual, but I honestly can't remember where I got them. Probably on a forum somewhere, but damn...old age and memory don't go well together. If you can't find anything with a search, might be easiest to make an adapter and use the ECC99 (or E182CC) settings if one of those is in your TV-7 chart.

There was something I was going to say to that, but I forgot...

Oh yeah, that's a good idea on making an adapter! And wouldn't you know, I just got a batch of cheapo socket savers off Amazon.

Oh...what about the fact that pin 9 is different - shield (6n6p) heater center tap (ECC99)? Is that why you said make an adapter? If I plugged an ECC99 directly into the VH2 or FV, I might let the magic smoke out?

 

[Novik tube]

Looking a bit into this, I see that ECC99's come up as a potential cross. If I compare the pinouts, I see that the 6n6p heaters are in parallel across pins 4 & 5 with a screen/shield connected to pin 9. The ECC99 on the other hand has the heaters in series across pins 4 & 5 with pin 9 as a center tap on the heaters. In my mind those are not directly swappable. Am I wrong here? Mind you, I'm not even looking at numbers yet.

The reason I'm asking is that I'm trying to come up with settings for my TV-7 tester to test them. @bcowen have you found anything comparable with your tester(s) to test what you have?

Hello! I will give you some information on this matter.
6N6P has a standard 6 volt filament connection circuit 4 and 5 (pin 9 is a screen and is not connected to the filament)
also like ECC88 ECC85 6N1P etc
ECC 99 has 12 volts to 4 and 5 pins in series, this is the standard for heating ECC81 82 83 12AX7 and so on (9 pin is connected to the middle of the glow and allows you to make 6 volts


The pinout 6N6P coincides with the entire group 6922, ECC88 ECC85 and soviet 6N1P 6N23P, etc. (2 paralleled glows of 6.3 volts
ECC99 is one filament for 12 volts with a tap to the middle for 9 pins, as is done with ECC81.82.83 and 12AT7, etc. (for this reason, ECC99 must be used with a converter).
Most likely, this tube will work in Valhalla even without a converter, but with a glow of 6 volts instead of 12 - but I do not recommend installing it without a converter.


I want to share a very curious remark from the radio museum:
url https://www.radiomuseum.org/tubes/tube_ecc99.html

 

[KoshNaranek]

You all are making my head hurt. Has anyone tried the ECC99 in Valhalla?

 

[GumbyDammit223]

Hello! I will give you some information on this matter.
6N6P has a standard 6 volt filament connection circuit 4 and 5 (pin 9 is a screen and is not connected to the filament)
also like ECC88 ECC85 6N1P etc
ECC 99 has 12 volts to 4 and 5 pins in series, this is the standard for heating ECC81 82 83 12AX7 and so on (9 pin is connected to the middle of the glow and allows you to make 6 volts


The pinout 6N6P coincides with the entire group 6922, ECC88 ECC85 and soviet 6N1P 6N23P, etc. (2 paralleled glows of 6.3 volts
ECC99 is one filament for 12 volts with a tap to the middle for 9 pins, as is done with ECC81.82.83 and 12AT7, etc. (for this reason, ECC99 must be used with a converter).
Most likely, this tube will work in Valhalla even without a converter, but with a glow of 6 volts instead of 12 - but I do not recommend installing it without a converter.


I want to share a very curious remark from the radio museum:
url https://www.radiomuseum.org/tubes/tube_ecc99.html

Thank you for verifying my concern! A lot of websites say tube x is "~equivalent" to tube y, but they never explain this equivalency. Apparently they are assuming the reader is much more knowledgeable about tube terminology than the average monkey such as myself and don't have to be told adapters are necessary. I'm glad my ample gut feeling was correct here!

 

[bcowen]

There was something I was going to say to that, but I forgot...

Oh yeah, that's a good idea on making an adapter! And wouldn't you know, I just got a batch of cheapo socket savers off Amazon.

Oh...what about the fact that pin 9 is different - shield (6n6p) heater center tap (ECC99)? Is that why you said make an adapter? If I plugged an ECC99 directly into the VH2 or FV, I might let the magic smoke out?

@Novik tube said it better than I could.