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回覆 (340): Good ECC83 /12AX7
I am not a big of the high mu ECC83 peanut valve but keeping a few would be handy for vintage or even 80s/90s amps. Recently accumulated a good number of E283CC. E283CC construction is identical to the very expensive ECC803s with the famous three mica and frame grid construction. Both Tele and Siemens have produced them.  
 
The only draw back is that the pin out is different to a ECC83. Not a problem if you are DIYer lor! Or simply build yourself an adaptor.  
 
Price already start climbing but still no where near a good condition Tele ECC803s. Get them before price shoot high!
bobui
13-05-09
15:32:05
回覆 (339): Hi Fi Technical Term - Held Hostage
A wife (CEO) heading home to her buddy Valve Hi End freak (VHF) after a tough day at work..........  
 
VHF: Ah! you home early. Hows work today?  
CEO: sucks! Sucks, sucks, sucks! I may need to go away for a few days to check out a factory somewhere near nowhere deep inside our mother land.  
VHF: Okkkkkk! That just sound so sweet to me! Ah ah!  
CEO: You what? Did you say something?  
VHF: No, absoutely not! Just missing you already! Ah ah ah!  
CEO: What the hell are you listening? Is that Adele? She sound so different...........Holy cow! What is this giant air con doing in our house? Wait a minute! Where is OUR favorite sweet little valve amp?  
VHF: Emmmmmm! Out on loan.  
CEO: What on loan? What? Now you telling me you are running a bank? Amp bank? Honey, the sound is kind of not..... very Adele.  
VHF: It just on loan. You see! A freind of mine want me to fix his amp which is this slightly larger amp sitting in our living room. So I loan him mine so he has something to listen to.  
CEO: Ah! I seeeeee.. I see now! Is it a deal? I mean what if you cant get his amp fixed? What if he prefer to keep OUR little amp instead? What if he not coming back at all?  
VHF: It really is just out on loan. Honey!  
CEO: The way I interpret all this is, our amp isnt really out on loan, its being HELD HOSTAGE.  
VHF: Honey, cool. Its not the end yet!. Everything will be alright. If its not alright, its not the end!  
bobui
13-05-07
15:18:50
回覆 (338): Enough is enough!
Some irresponsible sellers rebrand a Sylvania 6A5 and sell at bay watch as 6B4G. 6A5 is an indirectly heat valve. Other than the faliment, the valve spec is similar to 2A3 and 6B4G  
 
These fake 6B4G usually comes in straight bottle but some Italian versions also in coke bottles. Be extra cautious when buying lor!  
 
 
 
bobui
13-05-06
14:10:10
回覆 (337): Enough is enough!
Forgot to mention, if you wanna try 6B4G, I've read articles that the sylvania ones aren't direct heat, not sure if it's true, so to play safe, try to avoid them.  
 
In case u don't like Octal, there's one with 6.3V tetra base, the 6A3
Derek2A3
13-05-06
11:30:42
回覆 (336): Enough is enough!
I had this idea of building a 100W amp utilise 8 pairs of 6B4G per channel  
_______________________________________________________________  
 
Really something to die for if implemented properly.  
 
6B4G like bobui said is a bit cheaper than his brother 2A3, it runs with a 6.3V filament vs the standard 2.5V, and goes with an Octal base. Other than that everything is the same, including it's sound. In fact I ran side by side Sovtek 6B4G & 2A3 for a short period.  
Derek2A3
13-05-06
09:14:01
回覆 (337): Enough is enough!
My typo earlier. I need 8 quads for two channels. Another 8 quads as spare valves. Sowter can make an output transformer of 600 ohms a - a, 500ma per anode/side 150W.  
 
Its a very possible project!
bobui
13-05-03
12:45:21
回覆 (336): Enough is enough!
After hours of testing on the AVO, I can only identify 5 quads of the same brand that are close enough to be served in the same amp. I need to have at least 8 quads in total (4 quads for two mono blocks and 4 quads as spare valves) to make it worth the effort for such a large amp. Not enough yet!  
 
In the mean time, I have completed the power supply circuit in my long waited 811-10 Parallel push pull. Should be able to share some photos with the high hands here very soon.  
 
bobui
13-05-03
12:24:27
回覆 (335): Enough is enough!
 
 
I had this idea of building a 100W amp utilise 8 pairs of 6B4G per channel  
________________________________________  
 
 
Go ahead, what a waste otherwise !  
 
limage
13-05-03
11:04:12
回覆 (334): Enough is enough!
Three most common 6B4G.  
 
Far left RCA is the double plate construction: Two identical plates parallel.  
 
In the middle is the twin plate consturction: Two anodes, faliments and grids under one structure.  
 
Smoke version: Can be double plate or twin plate! Can see through anyway!  
 
 
 
bobui
13-05-03
10:14:01
回覆 (333): Enough is enough!
Spent a very large part of yester- evening not on beer bottles with the high hands but Instead, I headed home to measure the health and fitness on these coke bottles with my AVO160.  
 
6B4G  
One of my all time favourite output valves. Its basic character is identical to the 2A3 except the higher faliment voltage and lower market price. For a pair in push pull, output is roughly 10W max. The 6B4G came out a little later than the 2A3 and there is no single plate version. Only the twin-plate or double plate. Each half of a 6B4G (per plate) is similar in character to a 245 or 45. Basically, they put two 45s into one coke bottle and named them as 6B4G!  
 
There was one time I had this idea of building a 100W amp utilise 8 pairs of 6B4G per channel. Look to me Enough is not enough lor!  
 
 
 
 
bobui
13-05-03
10:01:17
回覆 (332): MC Transformer
What cow to buy for your MC cartridge?  
 
Dont have a conclusion yet until I have time to conduct my second round of shootout on the other group of cows, i.e., Tamura, JS, Sansui etc.  
 
So far. I do say if you like vintage, the Gardners and the UTC HA100X. For new stuff, the Lundual LL1636 (double coils primary windings).  
 
In terms of measurement, the Sowter can go to 60Khz with only a +-0.5db. If you look at the UTCA11, at 20Khz already in +-2db. But then, I am sure you aware human hearing is one of the worst in the animal kingdom lor!  
 
Only the Sowter and Lundual are easy obtainable. Sorry lor but if money is on your side. Please go for Tango and UTC HA100X. I still see them around in bay watch!  
 
How does the Tango or UTC HA100X compare with a stock/branded cow?  
I have a EAR MC3 cow. And sorry to let you know, may have to come near last in this group lor!  
 
bobui
13-04-29
12:59:39
回覆 (331): MC Transformer
Ah, here is the winner photo  
 
Morch 12", AT 40th and Tango MCT-999
bobui
13-04-29
12:34:06
回覆 (330): MC Transformer
A shootout - Soon after a home made full English breakfast on a lazy noon sunday, I took CEO along with me for a shootout on the first group of twelve MC cows.  
 
Three short pieces of music were played on three different LP set up. Miles-Kind of blue, Chopin 1st piano concerto and Michael Jackson Thriller.  
 
1. Home made suspension turntable based on Linn bearing and springs. Manticore power supply and a Morch 12'. Cartridge is the Audio Technica 40th.  
 
2. Alphason Sonata, HR100s, Atlas power supply and Ortofon Rohmann.  
 
3. Heybrook TT2, TPS power supply, Terminator and Ortofon MC30 Superme (new).  
 
And the winner is ..........below photo lor!  
Tango with 12"Morch and AT 40th is the sure winner on all three pieces of music.  
 
A close second is the Terminator/Ortofon MC30S and Tango or UTC HA100X. More details mid but voice not liquid lor! A little too much for long listening.  
 
To my surprise, the Jensen is a mellow cow. Very easy on the ears.  
 
Gardners MU7534, OK la!  
 
Sowter 9570, very detail treble but a bit too dry for me  
 
The worst? My ears lor!  
 
 
 
bobui
13-04-29
12:32:49
回覆 (333): Re: 811 transmitting triode
 
 
get it.  
 
limage
13-04-26
09:29:54
回覆 (332): Re: 811 transmitting triode
Hi Limage,  
 
Pin out same as 300B. Change faliment voltage to 6.3 instead of 5.  
bobui
13-04-26
09:04:40
回覆 (331): Re: 811 transmitting triode
 
 
bobui,  
 
To my greatest surprise, my AVO manual does not have 811 listed. Do you have equivalent ID number I can work with?  
 
BTW most 811 have the anodes on the top of their heads, but the 2 you gave me for test are different. Any advice on this issue?  
 
limage
13-04-26
07:32:02
回覆 (330): Re: "O mio babbino caro"
"......acceptance of her lover."
davidchan
13-04-23
21:03:57
回覆 (329): Re: "O mio babbino caro"
IMO, Victoria de Los Angeles owns this, demonstrating the contrasting moods behind the begging to the father for acceptance of her love.  
 
However, most sopranos, especially during recital encores, sing it in such a way like a girl to her lover, or even worse, a mom to her son!  
 
Hope you like it:  
 
http://youtu.be/9mViZx5Z3OU  
 
davidchan
13-04-23
21:00:02
回覆 (329): MC Transformer
Some of the cows from my farm! A shootout will be conducted.  
 
First row from left:  
Lundahl LL1636 double winding primary coils, 1:10 low impedance  
Jensen JE-642-90, 1:20 low impedance  
Sowter 9570, 1:10 low impedance  
 
Second row from left  
Gardners MU7534 1:20 mid impedance  
Partridge 973 1:10 mid impedance  
UTC A11, 1:10 mid impedance  
 
Third row from left  
Tango MCT-999 1:20 low impedance  
UTC 100X 1:20 low impedance  
Parmeko R3001, 1:10 mid impedance  
 
Cable: VdH 501  
Turntable A: Alphason Sonata, HR100s and Ortofon Rohmann  
Turntabel B Heybrook TT2, Terminator and Audio Technica AT33 45th Ann.  
 
US, British or Japanese Prime cut?
bobui
13-04-23
17:25:52
回覆 (328): Father's birthday
 
 
 
 
More peaceful!
bobui
13-04-19
06:42:25
回覆 (327): Father's birthday
 
 
You have to listen to Rita Streich, one of my favourite.  
 
 
 
cpsjj
13-04-18
19:53:21
回覆 (326): Father's birthday
 
C-hing, thank you for sharing ...  
... and I thought Angela Gheorghiu was pretty good too for the 近代 soprano until I hear Montserrat Caballe, she can still classify as 近代 I suppose, quite amazing ...  
 
Angelea was ok as soon as A/B compared ...  
Cadiver
13-04-18
12:54:47
回覆 (325): Father's birthday
 
 
Of course "O Mio Babbino Caro" la !  
 
 
 
 
 
cpsjj
13-04-17
22:38:01
回覆 (324): Father's birthday
Ah! A long time English lady friend just called and want me to suggest an English song for her to sing in his father's 70's birthday. I said, okkkkk ka!!! without having a bloody single idea what to recommend. Surely not a song from Sting. I then asked her if her husband can play guitar. If so, here is one.  
 
This song appear twice in the movie. God, that was an awful long time ago when we were young and foolish. Here my last sharing of the day with you high hands. You not 70's yet. Are you?  
 
http://vimeo.com/60309434  
 
bobui
13-04-17
20:08:16
回覆 (323): Max anode voltage AVO valve tester
Super! Will pass on two tubes for testing require negative voltage greater than -40. Thanks a lot!  
 
bobui
13-04-17
19:33:06
回覆 (322): Max anode voltage AVO valve tester
 
 
Mine is 400V and -100V respectively  
 
 
limage
13-04-17
19:04:37
回覆 (321): Max anode voltage AVO valve tester
Limage, can you please let me know the max anode voltage and negative bias voltage in your AVO tester?  
 
I am working half way through my very glassy looking 811 PPP mono amps. Need to define a reference point for valve matching. My AVo only goes up to 400V anode and -40 negative bias.
bobui
13-04-17
18:50:37
回覆 (320): Jimi Hendrix
You guys like Electric guitar. Then you must know this. One of Jimi Hendrix most famous sound "Little Wing". This version is by Sting. More user friendly. The solo guitar still very special ar! You like? Play it loud la!  
 
bobui
13-04-17
17:30:58
回覆 (319): Valve testing AVO 160
Much appreciated for getting the four KT88s measured on your AVO. Fish on me la! Thanks for being the reference point!  
 
10% higher in the trans-conductance is not ideal for me. 5% is what I want to aim for. Surely you realise the trans-con measure is a bit tricky and time consuming on the AVO-160. Sometimes, I have to wait more than 10 mins for the valve to settle before taking measure on the tran-con. Would make slight adjustment to bring my AVO 160 to closer tolerance.  
 
bobui
13-04-14
20:42:59
回覆 (318): Valve testing AVO 160
 
 
bobui,  
 
Scores on anode current is very much the same but on trans-conductance, your CT160 does show a higher reading by about 10%. This is not surprising since the measurement of trans-conductance on the 160 is rather tricky and scores can hardly be consistent every time.  
 
 
 photo P1080598.jpg  
 
 
This tube for example only achieves 70 and 7300 respectively on the VCM163.  
 
All 4 KT88 are okay except one which is probably starting to wane.  
 
 
limage
13-04-14
12:58:11
回覆 (318): Late night lor
Just finished a bloody conference call. So bloody XYZ! Missing my Prime rib dinner with the gang.  
 
A song for myself  
 
bobui
13-04-11
22:15:26
回覆 (317): Valve testing AVO 160
thanks.pm me your bank account.
drwkng
13-04-09
13:28:13
回覆 (316): Valve testing AVO 160
Good Doctor and Bobui, your foams have been ordered  
 
 photo file_zps453b907a.jpg  
 
daiwok
13-04-09
13:07:55
回覆 (315): Valve testing AVO 160
Ah! Welborne. So sorry ar! Got carry away by all these Turntable (daiwok) and CAS (Limage) stuff lately.  
 
Of the six TLF EL84s i have, only four measured well above average. As the English say, p[ain in the neck and Limage is right on judging them over their appreance. Not top notch lor!  
 
Since only four are ok! I would rather suggest you take them out to have a go and let me know if they sound any good to you as I dont have an amp to hook them up.  
 
bobui
13-04-08
22:43:32
回覆 (314): Valve testing AVO 160
Bobui,  
 
are you talking about the Tfk EL84? or..
Welborne
13-04-08
19:45:15
回覆 (314): Valve testing AVO 160
 
>Big operation need big encouragment! <  
___________________________________  
 
Ask and you shall receive! :-)  
 
 
 
thekong
13-04-08
16:30:24
回覆 (313): Valve testing AVO 160
Now, please come over to check out the amp! ;-)  
------------------------------------------------------------------------  
 
Big operation need big encouragment!  
 
bobui
13-04-08
16:15:38
回覆 (312): Valve testing AVO 160
 
BTW, please let us know how these reissue GL KT88s compares to your NOS GEC!  
 
thekong
13-04-08
15:48:42
回覆 (311): Valve testing AVO 160
 
OK, that is good news, thanks!  
 
Now, please come over to check out the amp! ;-)  
 
thekong
13-04-08
15:47:18
回覆 (310): Valve testing AVO 160
Testing results  
 
Measurement  
1. All eight tubes looking good on my AVO160. I have mreasured the cathode current "ma" for a given negative bias and the gm ma/V  
2. One tube deviate from the rest at a lower 63ma reading whereas the rest are all in the early 70's region  
3. I just spoke with high hands Limage and I couldnt agree with him any less on the white mirror side getters issue. The answer is "FINE". No big deal. It shows the tubes has been in use but still has good life left for playing  
 
Summary  
All good and still has plenty of life left. No problem.  
 
What I like to do next is to send four tubes to Limage to have them measured on his AVO. This enable me to find out the accuracy of my AVO160 and to discover if these tubes which have once been measured by him may actually carry different readings similar the testing figures i have.  
 
The other four tubes will be hooked up to my amp for a listening test! Ah ah!
bobui
13-04-08
15:34:35