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回覆 (344): Upcoming in Hong Kong, April 2016
Like to remind all high hands that Joshua Bell and Arcadi Volodos soon to be in Hong Kong. Grab your chance to hear them live la.  
 
Here is one of my all time LIKE from Cilburn interpretation of Appassionata. Enjoy!  
 
 
bobui
16-03-13
11:10:03
回覆 (343): Big Horn
comes with lots of large amps.
bobui
16-02-12
14:15:30
回覆 (342): Big Horn
bobui
16-02-12
14:10:22
回覆 (341): Big Horn
bobui
16-02-12
14:06:22
回覆 (340): A tough year
Its a tough year coming, as most is being told. The question is 2015 tough or 2016 tougher?  
 
To get through difficult times, my remedy is...............family a.....nd stay put to your love one.  
 
Wish you all a fruitful year coming!  
 
 
 
bobui
16-02-07
21:45:11
回覆 (339): Lenco
Glad you like the wooden base. It cost a lot more than the turntable and was air into HK.  
 
The motor is a smart design where you can adjust the speed without the need to mess around with the AC 50Hz. The spindle and bearing house is well made consider there was no CNC in the 60s -70s.  
 
Sold my Garrard 301 long ago and not miss it much but this Lenco, likely to keep close to my heart for a while.  
 
And, here I thanks to Daiwok!
bobui
16-01-22
11:25:48
回覆 (338): Lenco
 
 
I like the wooden base. So beautiful.  
 
limage
16-01-22
10:53:29
回覆 (337): Lenco
Burael - TT2 with a Mercury!  
 
bobui
16-01-22
10:40:14
回覆 (336): Lenco
Strip and spray! New toy in fighting for a space to squeeze in between her older sisters.  
 
Surprisingly stable sound without a power supply.
bobui
16-01-22
10:38:25
回覆 (335): Anna Netebko is coming to Hong Kong
The most wanted Russia soprano of the 21st century sings the most loved song from Russia. Lovely!  
 
 
bobui
16-01-03
20:20:05
回覆 (334): Mozart Horn Concertos. "The one and only"
Home early last night and put on a much loved record of mine and repeated it three times. The one and only best performed Mozart Horn Concertos by Dennis Brain. Original recording was first published in Mono by Columbia. He did it so cheerful and lively even when in mono!  
 
Not really much need to look for anyone else. Only Dennis Brain with the Philharmonia and Karajan.  
 
Here is a the No.1. Enjoy!  
 
bobui
15-12-08
14:14:45
回覆 (333): Valve LCR phono preamp
Perfect description, Cadiver. Reminds me the song "These are the days of our lives" - QUEEN. Last song written by the Freddie Mercury.  
 
My next project coming is the 200W SV811-10 mono blocks which I started over a year ago. Six SV811-10 per channel. Stay tune if it trigger your hi fi senses!
bobui
15-11-18
19:32:10
回覆 (332): Valve LCR phono preamp
 
Don't eat anything (except a piece of butter to coat the stomach) and the puke follow by pass out was the best part !! Sleep all day and no headache (only with good stuffs). Find bruise everywhere the next afternoon.  
If you ate, then the puke was painful especially if they came out from the nose.  
When 2 or 3 guys all puking the same time, it was really fun .....  
In the US, it's piss everywhere, in UK, it's puke everywhere .... That's the distinction I observed over the years.  
 
Cadiver
15-11-18
03:00:03
回覆 (331): Valve LCR phono preamp
My personal best was six pints back when I was in my early 20s. The drinking wasn't the difficult part when u got to the sixth pints. It's the walking in the freezing cold to search for the next pub that is most killing lor!
bobui
15-11-17
23:13:10
回覆 (330): Valve LCR phono preamp
 
That sounds awesome !!
Cadiver
15-11-17
15:52:46
回覆 (329): Valve LCR phono preamp
You know what. You've heard the term "Pub Crawl", right?  
 
The act of going to multiple pubs in a single night and have a pint in each pub until you pass out.  
 
I was thinking taking the LCR to many of the high hand's dens to...........You know what I mean????  
 
 
 
bobui
15-11-17
15:22:56
回覆 (328): Valve LCR phono preamp
Congratz!  
 
But your nightmare is coming, we, the evil group or 粉腸顧問團will allow you 3 months to burn in your new toy. Then, we will 踩場 to witness ourselves how lethal this weapon of massive destruction can be.
Derek2A3
15-11-17
15:14:05
回覆 (327): Valve LCR phono preamp
Oh! Sorry, should be this one. The final!  
 
bobui
15-11-17
10:30:23
回覆 (326): Valve LCR phono preamp
One final picture of my Burael P250. Enjoy!  
 
bobui
15-11-17
10:23:42
回覆 (325): Valve LCR phono preamp
When its properly executed, LCR RIAA wins by a far margin compare with any other types of RC or whatever types RIAA I have listened in the last 20 yrs. Smooth and realism with dynamic and lush!  
 
Specification of my Burael P250 LCR phono:  
Total max amplification: 80dB (1:40 internal mc transformer)  
Minimum amplification: 68dB (1:10 internal mc transformer)  
MM Input sensitive: Input 4mv, output 1V  
Power supply noise: 5mv AC ripple at 250Vdc  
 
I have not got round to measure distortion from my HP analyzer yet. Too busy just to enjoy the music! Let you know more in the near future. Of course, is a very low noise phono la! Need not to worry.  
 
Construction notes:  
The Good: Total accuracy and consistent. Since, I have a pair of LCR. I did a reversal test on the scope and the curves match exactly before construction begin.  
 
The Bad: Expensive! Very expensive compare with any other type of RIAA production due to higher cost of the LCR transformer. In a common RC type RIAA, a few low value caps and some low power resistors would be all you ever needed to bring the RIAA response curve down! And because the caps in the feedback loop needed not to be large in value, typically a few hundreds pf to a few thousands pf. You really cant over spend lor!  
There are just a handful of brands still produce the LCR transformer for DIY. Price roughly range from USD400 to 4000 a pair!  
 
The ugly: Nearly all LCR transformers are made to the Tango original specification. Meaning 600 ohms in and output impedance. Very hard to design a tube circuit that can offer 600 ohms or lower impedance with sufficient gain. Surely, tubes are never famous for being a low impedance device compare with their younger brothers FET or transistors la!  
 
In any DIY projects, I suppose the toughest to get right is always the making of the chassis and not letting the overall appearance looking like a dog shit. Keep your laughter to yourself please for the pictures I've posted below/earlier. Would try harder next time!  
 
 
 
 
bobui
15-11-17
10:05:11
回覆 (324): Valve LCR phono preamp
Thanks for your kind words!
bobui
15-11-13
11:37:42
回覆 (323): Valve LCR phono preamp
Nice job, bobui.  
 
Couldn't wait to learn how it sounds esp when it is LCR.
Derek2A3
15-11-13
09:49:47
回覆 (322): Valve LCR phono preamp
The two Nixie tubes indicate volume level from 0 to 24 steps  
 
Valve line up:  
E88CC X2 and 6J5 X1 per channel  
 
Phono Input:  
MC X3  
MM X2  
 
MM input loading:  
47k, 100k or 200k (Selector on front panel)  
 
MCT-999 MC transformer selection:  
1:10,  
1:20,  
1:40. (Jumpers underneath the main unit)  
 
Line input  
X3  
 
Output:  
Single Ended or Balanced (Selector on front panel)  
 
bobui
15-11-12
17:43:48
回覆 (321): Valve LCR phono preamp
Left - Power Supply  
 
Right - Main Unit of Phono and preamp.  
Smallest Tango from the rear is Tango MCT-999  
Middle Tango in white is the Tango EQP600 LCR  
Near the front panel is Tango N-126 Line output transformer  
 
Specification and test reports coming after the weekend!  
 
bobui
15-11-12
17:34:16
回覆 (320): Valve LCR phono preamp
After many hrs of hard work and sleepless nights. Finally, the LCR phono/preamp is coming to its final stage before its ready to reproduce music.  
 
Here is an inside look!
bobui
15-11-12
17:27:20
回覆 (319): Valve LCR phono preamp
Got a LM338K and home early today to solder it onto power supply of the LCR phono amp.  
 
The LCR not yet done. So, in the meantime, here is my all time best from G Michael.  
 
One more try. The music , the lyrics and the voice. A 1998 vintage of 100pts.  
 
bobui
15-10-06
19:20:09
回覆 (318): Valve LCR phono preamp
An all valves Series Regulator where the B+ enter the Anode of a power valve and in the below case, is an EL84. The B+ output for the load is taking from the Cathode of the EL84.  
 
See the principal difference between Shunt and Series?
bobui
15-09-23
14:31:59
回覆 (317): Valve LCR phono preamp
A typical high power valve Shunt Regulator. You see the there is no breaking on the B+ . Just chokes in the B+. All the regulator tubes are positioned parallel to the load.  
 
bobui
15-09-23
14:26:27
回覆 (316): Valve LCR phono preamp
Yes, meaning the max load is 40ma in a shunt.
bobui
15-09-21
10:54:20
回覆 (315): Valve LCR phono preamp
If the 6V6 and 0D3 are both parallel with the load, then you might want to double check the total current consumption. As the two tubes above together could easily take up 40ma.
Derek2A3
15-09-21
09:27:04
回覆 (314): Valve LCR phono preamp
Yes, the 6V6 is also parallel to the load. In traditional Series regulator, the output voltage is usually taken from the cathode of a power tube such as a 6C33 or EL34. In Shunt regulator, whatever that is not required by the load is consume by the regulator.  
 
Cadiver, shunt regulator is not efficiency and hardly seen in brand product. Even less common using valves due to is low efficiency. In series regulator, the main regulator transistor or valve is in the top half of the voltage divider. In Shunt regulator, the main regulator transistor or valve is in the bottom half of the voltage divider.  
 
Meaning in Series regulator, the main regulator transistor or valve is in series with the load. Whereas, in shunt regulator, the main transistor or valve is in parallel with the load.  
 
In shunt regulator, there is nothing but a resister comes between the power line and the load. In series regulator, as its name suggested. There is always a regulator be it transistor or valve comes between the power line and the load in series.
bobui
15-09-19
15:22:50
回覆 (313): Valve LCR phono preamp
What r u guys talking about ?? !! :-)  
Never mind, don't answer ....
Cadiver
15-09-19
14:09:21
回覆 (313): Valve LCR phono preamp
What r u guys talking about ?? !! :-)  
Never mind, don't answer ....
Cadiver
15-09-19
14:09:20
回覆 (312): Valve LCR phono preamp
The 6V6 and 0D3 is in parallel with the load.  
______________________________________  
 
Is the 6V6 also parallel with the load???  
 
 
Mach - Ratio of true airspeed to the speed of sound. You know this one la.  
___________________________________________  
 
You better be careful with this, if your phono amp's output is entering the Mach region, all you can hear may be only noise
Derek2A3
15-09-19
12:16:16
回覆 (312): Valve LCR phono preamp
Here is a preview of the knobs i have bought for use in the main chassis as selectors. They were genuine US aircraft surplus!  
 
DOP - Dilution of Precision (GPS)  
 
ILS - Instrument Landing System  
 
Mach - Ratio of true airspeed to the speed of sound. You know this one la.  
 
Cool stuffs?  
 
bobui
15-09-19
10:43:52
回覆 (311): Valve LCR phono preamp
The 6V6 and 0D3 is in parallel with the load. For this particular reason, its desirable to locate these two valves close to the load. However, due to the limited space left after the main circuit in the main chassis, I am being offered with no option whatsoever but to separate the power supply from the main unit.  
 
I did consider about putting the rectification and the rest of the regulator circuit into the main chassis and leaving just the six transformers in the power supply but that would leave me with plenty of AC voltage lines running across the two chassis which is not ideal.  
 
Derek2A3, I think u have raised a very interesting subject regarding location efficiency. Commonly, people tend to believe that power supply separated from the main amplification is ideal in all circumstances but if look closely, its not hard to realize sometimes the benefit is overshadowed by the problem it created.  
 
The 0D3 together with the 6V6 are the unnecessary evils to draws current to maintain voltage, worst if I replace it with a zener due to its high noise. Anyone got any recommendations, feel free to show yourself please. 40ma, 250V is all I asking for each channel lor!  
bobui
15-09-19
10:19:24
回覆 (310): Valve LCR phono preamp
Looks promising, congratz.  
 
So you are combining series and shunt regulation? Or the E180CC + 6V6 together form a constant current source?  
 
The 0D3 gas regulator should be more efficient when placed close to the gain stages. Just my 2 cents
Derek2A3
15-09-19
08:40:19
回覆 (309): Valve LCR phono preamp
My CEO said it look like I took it out from North Korean!  
 
bobui
15-09-18
08:50:41
回覆 (308): Valve LCR phono preamp
Looks nice !
Cadiver
15-09-18
05:04:10
回覆 (307): Valve LCR phono preamp
Picture below is the belly of the power supply before soldering. Test on the supply will be commenced this weekend. Two steady 250V HT rails is what I expect after a few months work since the day I started off with the drilling and cutting of the chassis.  
 
The supply employ total of eight valves for the two channels. A GZ34 rectifier. 6V6, 0D3 and E180CC in the shunt regulator.  
 
The large dial on the front panel allow instant DC voltage check. Adjustment to a correct voltage on the right hand size of the front panel where u see a small toggle switch.  
 
The funny looking black straps yellow switch is the high voltage "Launched" button. The switch itself is actually from a F18 jet fighter!  
 
More pictures coming for the LCR phone main unit in a few weeks.
bobui
15-09-17
13:59:40
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