PCC88s vs 6922s

[admin]

Interesting. Tubes failing at 200 and 500 hours is certainly not expected (or ideal). I'm sure this will be helpful for ET5 users as personally I would not go with tubes that fail with such low hours.

[AnotherJohnson]

Just an update on tube longevity as I needed to replace the Matsushita 7dj8/pcc88 recently in my ET5. I keep track of listening hours. It lasted 500 hours and then sounded dull and lifeless.

Reading the list, it appears that none of these tubes specifically failed per se.

They did not get “noisy” or “quit.” They just lost their edge compared to what the poster had liked about them earlier in their life. Of course it is a legitimate reason to change, but another listener with another systems, like admin for example,” might not have thought they were ready to change.

With my ET3SE, two ET7s, and ET7s2, I found some of the OEM tubes to get noisy more quickly than I would like, and I would replace them for that reason. But the replacement tubes (typically EH 6922 platinum grade from Upscale) performed noise free for a longer (considered normal) period.

Last year when I was moving into ARC REF gear, I traded my PH8. I ran into the fellow who it turns out bought it. We did not know about this common gear … and we were discussing tubes and tube life.

He commented on how he’d bought a used PH8 recently with xxxx hours on the tubes. It had not sounded good to him. But he changed all the tubes and now it was spectacular. He was very happy.

I recognized xxxx as the number of hours on the PH8 I’d traded, and I asked him when and where he’d gotten it. It was my old unit which still sounded great to me and to the dealer who took it in trade to resell.

My point is that many people seem incredibly sensitive to how individual tubes affect the sound of their gear. Others are less sensitive. And at the other end of the spectrum, there are people who refuse to replace a tube until it is either red plating (power tube), snap crackle popping (first stage in amp), hissing loudly (preamp), seriously distorting, or silent.

[Music Matters]

Yes AJ you are correct. The Gold Lion and Matsushita just went lifeless and dull in my opinion and my system lacked dynamics. They were quiet though, and did not fail. The EH6922 also went lifeless and dull but also some got quite noisy with hiss as well. But none of them failed. Remember this is also very small samples as well, so just my experiences in my system. Maybe I will try a Gold Lion 6922 again in the future as I loved the sound before it went lifeless and dull, and shouldn't judge on a sample of 1 tube! Out of interest how long are others getting in ET5 or similar preamps like ET3/67/GAT etc?

Kind regards,

Graham

[AnotherJohnson]

Out of interest how long are others getting in ET5 or similar preamps like ET3/67/GAT etc?

In my own case with all three brand new ET series preamps I’ve owned (one was bought used), the factory installed tube sounded good after a day’s use, but displeased me before the first year was out due to increased noise floor.

If you read through this thread from page 1, there are a lot of anecdotal data.

People do have personal expectations for their tubes. And why not? Being able to change the tubes is a feature of tube gear.

[Music Matters]

Thanks AJ. Yes I had read all the thread from Day 1. So roughly after a year of your listening they increase in noise floor for you...do you know approximately how many hours that is as a year of listening is fairly ambiguous! I have been in this hobby a while and owned from new a pv10a, pv14l, ev1, premier 11a and mv 55...the only CJ amp to go through tubes quickly is my current ET5...all other CJ gear has been not as hard on tubes

Kind regards,

Graham

[roberto]

Hola Chicos,

Just thinking loud. The new NOS tubes are made on these days with different conductivity materials and have much better signal to noise ratio, but these new materials are not lasting as they should. I got lucky with the previous 6922 Gold Lion gold pins, and it is still working as good as like new. A different history I have with another Gold Lion gold pins...it last only 7 months and got a noisy hissing right channel. I put another and the noise went away, and the quality is fantastic.

On the other hand, these New Old Stock is amazing. The sound quality that I am getting is as good as the Philips Holland made with super wide stage and stunning clean sound quality. Harmonic textures are granted, and easy to understand what is happening with the musicians and their communication with each other too. This is a fantastic feature for me!.

I have my fingers crossed...I hope that I got a bad Lemmon...we know that these small signal tubes do fail a lot. Old tubes exhibit a longer life span.

Happy listening!

[AnotherJohnson]

Thanks AJ. Yes I had read all the thread from Day 1. So roughly after a year of your listening they increase in noise floor for you...do you know approximately how many hours that is as a year of listening is fairly ambiguous! I have been in this hobby a while and owned from new a pv10a, pv14l, ev1, premier 11a and mv 55...the only CJ amp to go through tubes quickly is my current ET5...

In those days I had several systems to listen to and it’s hard without logging the hours to report. My sense is that those three new ET series preamps got hissy in the same range that report, ie a few hundred hours (in less than a year).

I have one system to listen to now. The preamp has been in service about 6 weeks. It is showing 270 hours on its clock.

[Big Dog RJ]

Attn: Music Matters

Nice write up mate and comparisons on tubes.

Agree on the GGL's, they're always special sounding but don't last too long either compared to the EH version, which according to my local tube supplier in Melb, they're both identical! Same construction, same factory, same process.
According to him on his latest measurement data using the various tube testers he has on his work bench, there are slight variations in gain, this is where it varies, so tube matching is important.

Since you're using the ET5 which has just one tube, that's not too shabby... however, in my case I require matched pairs for my monoblocks. Agree on the NOS types, there's something extra special going on here... but Matsushita hasn't made tubes since the first Toyota Land Cruiser came off the assembly line... so these Japanese NOS are really NOS! Such that, I bought a few at some fancy prices and they didn't last at all! Went poof in under 3 months! The seller wasn't budging that anything was wrong and swears that he tested them and were working perfectly before shipping off down unda... yeah whatever.

So, my days with NOS are off! Not going there anymore, just sticking with current production type and of course what the manufacturer recommends. CJ HQ has always been 110% accurate and honest with me when placing tube orders or specialised parts for mods... so far top notch service and my gear has lasted a lifetime!

If those NOS tubes hold out well then you're quite lucky... just as is the case with a good matched set of GGL's. Once a good batch has been identified, just stick with it!

Looks like you've found the type of sound you're after, so that's a good thing! Just sit back and enjoy those fine tunes!

Cheers, RJ

[Music Matters]

Thank you all for sharing your experiences. Very interesting to me and I think others reading the thread. Especially the difference between the EH and GL from the technician, even though very similar construction. On another note I have new production Mullard, GL, and Sovtek LPS all in 12AX7 for my CJ phono stage and have used all of them. These were purchased from the tube store tested and matched. The gain is always higher according to the tube store testing equipment on the GL than the new production Mullard 12AX7 and Sovtek 12AX7 LPS even though essentially all same/similar construction from same factory, which matches your technicians finding RJ with the 6992 EH vs GL.

Currently I have an old NOS Russian military spec 6h23/6922 EB premium in my ET5. I bought a few of them and put the oldest one in!!... 1972 as it is same as my DOB!! It's running in now and the initial stridency in the lower treble I heard has calmed down...or I've just got used to it!! Either way it's sounding great and I'll see how long it lasts.

RJ are you using the EH6922 from CJ now? I got my Matsushita from Watford Valves in the UK. He was very informative and pleasant. He basically said himself and Upscale Audio from the US bought most of the stock available for the Matsushita 7dj8. Yes I suppose it's hit and miss with batch you get for NOS. I bought a few 5751 NOS GE at quite an expense and they just sound bad in my phono stage, and they should be perfect as CJ used them OEM...but the new production Sovtek or Tungsol 5751 sound way better...so I think I may have got some GE 5751 from a bad batch...!

The Matsushita I put in that lasted 500 hours before sounding dull, lifeless and lacking dynamics, was factory tested...not tested and matched from Watford Valves. I do have some tested ones as well but have not used yet. I only buy tested ones now.

Kind regards,

Graham

[Big Dog RJ]

G'day Graham (music matters) ...in fact it does matter!

At the moment I'm using the GGL's 6922's on my monoblocks. The reason being, sometime back in early April then again in July and again in Oct 2022, the system started reproducing that annoying scratching noise...
I suspected it was one of the 6922's so I changed several versions, from GGL's to EH to Philips. It ended up being the Sovteks in the preamp! Nothing to do with the power amps at all! So after tube swapping to diagnose which bloody tube... I ended up placing back the GGL's, so I just let them sit there since last Oct.

To me or at least what I was thinking I was hearing is: on the GGL's the full spectrum is well balanced and the bass has slightly more weight to it. On the EH version, the midrange seems to be more profound and comes across with a greater presence. The rest of the freq spectrum is quite good but doesn't have the kind of bass compared to the GGL's.

I'm not really sure if this is accurate or whether it's all in the mind but from initial thoughts, as soon as I swapped these tubes, I noticed these changes.

The Philips OTOH has a lovely sound to it. Like silky smooth, everything is just a breeze, an absolute enveloping affect and a delight to listen to.

Both the EH and GGL's were sourced from CJ HQ and the Philips and my little Mullards M8080's are sourced from Watford Valves. Derek Rocco is a great chap, excellent customer service and I've never had a bad tube from him.
He's always mentioned about the variations in NOS type and has given me updated info to make better decisions but he's never given me the typical sales approach. I respect Derek R as much as I respect Jeff F. So far the other tubes are now carefully stored away as spares. That reminds me, I need to order some Mullards from Derek, since I don't have any spare M8080's!

All the premature tube failures I've had with NOS type and regular GGL's were bought from two stores in the US, which are listed on this forum. Since some have found them to be quite reliable... I won't mention the names since other owners are happy. Perhaps it was a bad batch... I don't know but it was several failures one after the other across a few months. Hence, I don't purchase from them anymore.

Now, I just stick with Watford Valves UK, CJ HQ and my local tube supplier who apparently sources directly from Russia, so he says! Maybe that's why he charges a premium! Plus he's got the full array of tube testing equipment and is a real tube nutty professor! He knows tubes! He's the chap who provided me with two sets of EH 6N30P gold pins for my preamp. The other one pair being another standard Sovtek 6N30P, which I'm keeping as spares. Speaking of which, I had placed another order of EH and Sovtek 6N30P's from CJ last Aug, and they've arrived at my CJ dealership since Oct. I haven't been out there to collect them... been enjoying the fine tunes!

I don't want to tube roll too often due to three things:
1. Tube rolling often will lossen the sockets.
2 Tubes itself take time to settle in, therefore allow a few 100hrs before deciding to change tubes.
3. Changing too often doesn't allow for a proper assessment, it becomes more tedious and confusing. Rather just enjoy the music!

Cheers mate!
RJ

[ELM]

Just an update on tube longevity as I needed to replace the Matsushita 7dj8/pcc88 recently in my ET5. I keep track of listening hours. It lasted 500 hours and then sounded dull and lifeless.

So what I have so far in my ET5 which may help folks: (in order of use since I bought new many years ago).

Hope this helps anyone looking for tubes for their ET5. Happy listening everyone.

Hi Graham (Music Matters),

Thanks for the sharing. Very informative indeed.

I am also an ET5 owner. Have been using it for 9 years and am still happy with it.

It is helpful to know about the compatibility with a 7dj8/pcc88. I thought of using this tube type for some time but was always hesitant for the 7V requirement vs. the 6.3V for 6922.

I have rolled a number of NOS European tubes over the years - Siemens, Telefunken, Mullard, Philip Watts and Tesla etc. At the moment I have settled in with a Siemens '63 CCa which gives me the necessary holography and sound stage to suit the music I often listen to. This tube has been with the ET5 for 3 years and it still runs strong.

I also used the EAT E88CC (actually from JJ Slovakia) for a short while but was not quite attracted to its sonic performance.

Just some sharing. I have no luck with the CJ stock tubes. I remember the EH6922 that came with my ET5 exhibited white noise within its first 50 hours. The local dealer replaced one for me but it turned bad again shortly - indeed it was those circumstances that started my journey for European tube rolling in quest of their reliability.

Last year I got my ART150 power amp which came with three Slovakia made E88cc (believe from JJ). Luck failed me again. Two out of three tubes displayed white flashes within the first 50 hours. As one of the failed tubes served in the phase split stage, I could hear obvious channel imbalance.

The local dealer reported the issue to JF who was kind to send me a set of replacement E88cc (x 3) immediately. Unfortunately history repeats itself. Again two out of three failed for the same symptom after 3 days of use. I did not want to bother CJ again as their inventory for that whole batch of tubes might have a fluctuating quality. Since those JJ tubes are not pricey and quite easily accessible in the market, I bought a match pair from Watford Valves. They have been working in my ART150 without any problem.

An interesting point is why CJ uses the JJ E88cc for my ART150 instead of EH6922 as stock tubes. I can only assume that Russian tubes have been getting increasingly hard to source, so they go for Slovakia tubes. Just my guess.

Happy listening. Sure I will check out the PCC88.

Cheers
ELM

[Joe Appierto]

The Philips OTOH has a lovely sound to it. Like silky smooth, everything is just a breeze, an absolute enveloping affect and a delight to listen to.

Just a side note, what you describe RJ is exactly why the Philips/Amperex brand were always among my favorites. Never irritating or grating and threw a soundstage that was very well laid out and dimensional.

[roberto]

I will add, a little bit more harmonic texture and detail Joe.
Happy listening.

[Joe Appierto]

[Music Matters]

Thanks all ...good discussion and sharing of experiences! Agreed RJ Watford Valves awesome in my experience too!

[Paolo]

I don't want to tube roll too often due to three things:
1. Tube rolling often will loosen the sockets.
2 Tubes itself take time to settle in, therefore allow a few 100hrs before deciding to change tubes.
3. Changing too often doesn't allow for a proper assessment, it becomes more tedious and confusing. Rather just enjoy the music!

Cheers mate!
RJ

As usual, excellent info from my CJ "mentor from down undah...." I especially appreciate the comments on tube rolling. I am now content and reaping lovely sonic and monetary rewards by "just letting 'em be." So thanks again....
Ciao Matey,
P

[goonybird]

Been following this.
Has anyone tried GE 5670 with suitable adaptor?
Ifi have just released a unit using these instead of 6922 and their article speaks highly of them
Most GE Jan 5670 are mil spec and cost way less than 6922.
Ihave just received some RCA 5670 to play with to keep costs down, and have adaptors. I guess i may have to leave the cover off my 17ls. Will update.

https://ifi-audio.com/wp-content/upload ... E-5670.pdf

[roberto]

It is not a direct replacement for the PCC88/6922. Read this: The 5670 pinout is radically different. Electrically and in terms of internal design it is very similar to the 6DJ8/6922 which became very popular in American high end audio gear, but one can't plug it into a 6922 socket.

There are 6922 with a very low price and are used mostly in guitar amplifiers. Their review are good. I use Genalex Gold Lion 6922 with excellent results. And are not too expensive. You can find them on Ebay or Amazon too. www.tubedepot.com also has them. There are many tube suppliers that have them.

https://www.thetubestore.com/jj-e88cc-6922

[goonybird]

It is not a direct replacement for the PCC88/6922. Read this: The 5670 pinout is radically different. Electrically and in terms of internal design it is very similar to the 6DJ8/6922 which became very popular in American high end audio gear, but one can't plug it into a 6922 socket.

There are 6922 with a very low price and are used mostly in guitar amplifiers. Their review are good. I use Genalex Gold Lion 6922 with excellent results. And are not too expensive. You can find them on Ebay or Amazon too. www.tubedepot.com also has them. There are many tube suppliers that have them.

https://www.thetubestore.com/jj-e88cc-6922

I posted I had bought Adaptors. also the link fully expains why to use 5670's and yes I have genelex 6922 Just interesting as not usually into "tube rolling"