Ugh - power noise! You know I had much pain with this. I am very glad to hear that you are in your new situation. May you settle well and quickly Glenn. I hope new work is good and that you get some peace and relaxation eventually.
I used to have such issue at country side.
I know the members of this thread appreciate a good tube picture, here is the Visseaux 6A5G with the MOV U18/20 in the back. So purdy, so glowy.
it was funny, they were glowing very brightly earlier in the day, I turned the amp off and swapped the two so I could get a good picture of the brighter one (better position for my camera), and it went away when I turned it back on HA! Luckily it came back later in the day, at the time the photo was taken, part of it was sort of blinking, but I didn't see if it was in time with the music, I'll look today.
I still find tube burn-in fascinating. At first, I struggled to keep the Mullard EL32 shoulders in (NOS 0hrs). They had some sort of subtle grit going and seemed to just remove what the other EL32s had added. Somewhere around ~25h of use and they started to change and relax. It is not subtle. They are enjoyable now putting back some nice space in the mids/uppers and roundness/control in the lower end. I suspect they will keep changing. I am glad I persisted. I have had the amp on for ~14h/ day every day, listening for a good portion of that on many days. After a week I should get to 100h or so and we'll see where they wind up. It is possible I guess they may take even longer to get to their final state as cooler running valves?Impressions on the new valves ASAP. I enthusiastically popped the Fivres in yesterday - but only for a bit. Given what I thought of as "questionable provenance" of the Fivres and their "used" status, I gave them an hour to warm, then around an hour on the sacrificial headphones. I was able to say "quiet" and a quick listen on my normal headphones said; "probably very nice".
I then realised I had just a few hours before swapped in Mullard EL32 shoulder-types seen in the C3g slots pictured below. They are new and sound like they need time to burn in. I have had my "go-to" GEC 6J5 inputs w/ the EL32 straight tubes (postal tubes like JV has). I think that is my most reliable, often returned to configuration. I want to get the shoulder-type Mullards burned in, and to isolate the effect of just changing those tubes. Therefore, I put the setup back as pictured. I'll let the EL32s pictured go for a week of many hours/day use. THEN I'll come back to the Fivres.
I am hoping the Mullard EL32s do burn in. So far, I have not had the patience to really let the Marconi straight glass EL32s or these Mullard shoulder types really burn in because the straight postal tubes are fully settled and sound so nice in this setup! I think the EL32s run pretty cool, so it may take a while...
Here are the "GPO" postal Mullard EL32s that have maintained their position int he amp for a while now...
I have been googling a bit to decipher the codes on these. General info on these tubes labelled CV 1052
It looks like:
How about the printed values visible on the left tube? These look like "MO 2" and "39 C2". Both tubes have the same markings. Not sure how to date them from this? Also, what is the "6914 with the up arrow looking thing" visible on the right tube? All fascinating!
- CV = Valves used by the British military Armed Services were marked with a CV or "common valve" name which was defined by the Inter-Service Technical Valve Committee in 1941
- KB/DA (via this link)
- K = designates a valve manufactured to specification K1001 or K1006;
- B = denotes qualification by a UK authority
- DA = Mullard Radio Valve Co., Blackburn
Happy listening all.
Love it when I learn something new
Do you mean warm-up or burn-in? Or both?
Hi,Since you brought up these tubes DL, I spotted the pair I own in the "6J5 drawer" and decided to give them a listen. I think you will be very happy with them
One interesting observation I've made: tube hierarchies I created in my mind based on listening impressions in the GOTL have fallen apart with a CCS load applied. This goes for both 6J5 and MH4-family tubes. The CCS is something of an equalizer, bringing all tubes closer together in performance, but accentuating different characteristics. The differences are still there, but the timbres have changed. A top tube in the GOTL might be taken down a peg or two in favor of those that were further down the ladder before. It has been a fun experience re-listening to them all.
Glenn often uses CCS loads in his SET amps, so maybe others will have a similar experience!
That is not a Glenn amp, although I am sure he helped talk to the maker.
Notwithstanding Covid-etc a listen would perhaps be in order.
Question to the tube experts regarding burn in:
