[abvolt]

Hi all, from Suffolk UK.

I personally adapted ECC31s for use in the 6SN7 slots of the Feliks-Audio Elise, and they were better than any 6SN7 tried!

Trouble was the heat they generated - so I went for the EL3N, then the EL11, which I (and others) found 'better' and ran the amp MUCH cooler. So you pays your money, and takes your choice!!

I will agree with that for sure, After I started trying the mullard eccxx's in my amp I sold all my 6sn7's..funny enjoy

 

[CZ4A]

Hi everyone, I'm new in this forum and this is between very few places when I saw a discussion about ECC31. I show you my collection of ECC31 that I got about 20 years ago and maybe you can give me some advice about the manufacturer and some data about testing them. I got them as NOS, 15 with brown socket and 9 with black socket. Brownies are all identical, with code 1029 1A4 visible on few tubes, but the black ones are at least two types and I'm not so sure that are really NOS. They are all QTL but as we know QTL is just a commercial brand, not a manufacturer one, so, who made them?

Sorry but I think I don't have the right to post images here as a beginner. Will come soon.

I don't think true ECC31s (also known by the British military designations NR73 and CV1285) were ever made by anyone but Mullard. Someone in the Feliks Elise posted a photo of a QTL-rebranded Mullard ECC31 here: https://www.head-fi.org/threads/fel...-6080-prototype.732875/page-133#post-11815816

For testing, if you have a tube tester but no ECC31/NR73/CV1285 setting, use the 6N7 settings. The ratings aren't exactly the same, but they are close. In any case, nice score!

 

[rosgr63]

Beautiful tubes, nice collection

 

[leftside]

Beautiful tubes, nice collection

Thanks. From what I've learnt the last few years, my photos should probably focus on date codes, micas, construction, etc. Perhaps I'll provide some updates at a later date.

 

[L0rdGwyn]

I purchased a NOS pair of Mullard CV181 tubes. I am wondering if anyone is able to decipher these date codes? Much appreciated!

I believe they read "1185 K1" and "1185 I1".

 

[Oskari]

I purchased a NOS pair of Mullard CV181 tubes. I am wondering if anyone is able to decipher these date codes? Much appreciated!

I believe they read "1185 K1" and "1185 I1".

See these for 1) my guess of the Mullard code, and 2) for the CV code:

1. https://www.head-fi.org/threads/ecc33-ecc35-tube-addicts.558352/page-3#post-9020495
2. https://www.valvecollector.uk/cv-valves.htm

 

[L0rdGwyn]

See these for 1) my guess of the Mullard code, and 2) for the CV code:

1. https://www.head-fi.org/threads/ecc33-ecc35-tube-addicts.558352/page-3#post-9020495
2. https://www.valvecollector.uk/cv-valves.htm

Thanks, Oskari! With 1185 being the pre-1955 Mullard code for the ECC32, and assuming K and I correspond to the months, I believe that would put these tubes in September and November of 1951. That will work for me, thanks.

 

[kartikey]

I purchased a NOS pair of Mullard CV181 tubes. I am wondering if anyone is able to decipher these date codes? Much appreciated!

I believe they read "1185 K1" and "1185 I1".

May I know where you purchased these from? I am trying to find ECC32-35 for my WA22.

 

[leftside]

I purchased a NOS pair of Mullard CV181 tubes. I am wondering if anyone is able to decipher these date codes? Much appreciated!

I believe they read "1185 K1" and "1185 I1".

The best! Can you see the getter type?

 

[L0rdGwyn]

The best! Can you see the getter type?

I don't have them in hand yet, but looks like a D getter from the photos.

 

[L0rdGwyn]

Well these came today, good timing ahead of my imminent Glenn OTL arrival. Threw them in my modified Bottlehead Crackatwoa for a test run. First impression, soundstage and resolution on these drivers is incredible. I am legitimately worried they have rendered a large portion of my driver collection obsolete...

 

[whirlwind]

Well these came today, good timing ahead of my imminent Glenn OTL arrival. Threw them in my modified Bottlehead Crackatwoa for a test run. First impression, soundstage and resolution on these drivers is incredible. I am legitimately worried they have rendered a large portion of my driver collection obsolete...

I know what you mean.
I could listen to ECC31,32,35 and TSBGRP maybe GEC B36 and a Brimer 13D1 the rest of my life and have no complaints

I have lots of driver tubes that will never see my amp again.

I like the ECC31,32,33 the best of the Mullard tubes, but everybody's mileage will vary, depending of what their ears tell them.

Rolling drivers is a lot of fun, but when push comes to shove....these seem to never disappoint me.

 

[L0rdGwyn]

I know what you mean.
I could listen to ECC31,32,35 and TSBGRP maybe GEC B36 and a Brimer 13D1 the rest of my life and have no complaints

I have lots of driver tubes that will never see my amp again.

I like the ECC31,32,33 the best of the Mullard tubes, but everybody's mileage will vary, depending of what their ears tell them.

Rolling drivers is a lot of fun, but when push comes to shove....these seem to never disappoint me.

That is a solid rotation! I'll have to see how it all shakes out with the GOTL. Looking forward to giving the ECC31 a listen too we'll see if I go all the way for the ECC33 and 35

I can firmly say that I am a fan of the Mullard ECC32 though, I am pretty certain they will be somewhere at the top of the list. I have been collecting and listening to some 6J5 tubes lately as well, there are some special ones out there.

 

[tintinsnowydog]

Reviving an old thread, but I thought this was the most appropriate place to post this. I received some NR73/ECC31 tubes today, and am trying to figure out the date codes. Was wondering if someone more knowledgeable here could be of help. So far the clues are that the plates are short and black, non parallel top heater shields, and a bottom rectangular cup shaped getter. The date codes are 1029.1 and 1MV; I have one other single ECC31 labelled 1029 and BJ which has slightly different plates, but the same getter and heater shields. If anyone knows how to interpret these that would be very helpful!

I guess what is adding to the confusion is the labelling on the boxes. The CV registry was established 1941, so should NR73 designation point to pre-1941? The boxes however are labelled 1963/69, and one labelled 1964/70. I have worked out so far that 'omprovas' means re-tested in Swedish, so retested in 1975.

My guess right now is that these were old tubes made in 19?? that sat in military stock, were packaged in 1963/69, then retested again in 1975, and were still never used. Hope to find out some more history!

 

[adamaley]

That is a solid rotation! I'll have to see how it all shakes out with the GOTL. Looking forward to giving the ECC31 a listen too we'll see if I go all the way for the ECC33 and 35

I can firmly say that I am a fan of the Mullard ECC32 though, I am pretty certain they will be somewhere at the top of the list. I have been collecting and listening to some 6J5 tubes lately as well, there are some special ones out there.

Which 6J5 tubes will you recommend one prioritize? I'm looking at exploring them.