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回覆 (270): tube tester
 
 
do you mean testing the tubes at the operating point of the amp?  
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Yes exactly. I’ve found that standard testing offers merely a guide line. Testing under conditions similar to actual  
operation gives the most reliable results.  
 
Pick the ones with sufficiently high gm or in case of matching output tubes, those with closest scores.  
 
 
limage
11-09-14
21:42:01
回覆 (269): tube tester
constant current source is surely fine if you offer adjustable for uncommon tubes. "One of a kind" sound fun and pro!  
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it will be adjustable. i'm not sure how fine the adjustment yet.
drwkng
11-09-14
16:34:42
回覆 (268): tube tester
programmable constant current source  
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constant current source is surely fine if you offer adjustable for uncommon tubes. "One of a kind" sound fun and pro!  
 
bobui
11-09-14
16:33:28
回覆 (267): tube tester
1. Octal, 4 pins US, 4/5pins UK, B9A and the option to jam the B+, bias, cathode and heater with crocs or something.  
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would it acceptable to manually configure the tubes using jumpers? if it requires the tester to automatically configure the connections, there will be huge number of relays required to do the routing.  
 
2. A mA meter for cathode current. Can manual set the bias level. max. 500V HT, A variable LT supply up to 15V 5A with voltage meter for 811, 845, 6C33C etc. A gm measure.  
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why do you need a ma meter? i'm thinking of electronically setting the cathode current using a programmable constant current source. i think most of us have access to a DMM, would it be acceptable to use the DMM to do the measurement instead of using the micro-controller.
drwkng
11-09-14
16:11:58
回覆 (266): tube tester
1. Octal, 4 pins US, 4/5pins UK, B9A and the option to jam the B+, bias, cathode and heater with crocs or something.  
2. A mA meter for cathode current. Can manual set the bias level. max. 500V HT, A variable LT supply up to 15V 5A with voltage meter for 811, 845, 6C33C etc. A gm measure.  
3. For me HK$3,000.-
bobui
11-09-14
15:57:32
回覆 (267): tube tester
there is hardly the need for a universal tube tester.  
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this is not what i have in mind. i'm thinking of a simple to use tube tester for some common audiophile tubes.
drwkng
11-09-14
15:44:20
回覆 (267): tube tester
What they require most is kind of  
simulator approximating the amps in use. ?  
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what does this mean? do you mean testing the tubes at the operating point of the amp?
drwkng
11-09-14
15:42:51
回覆 (266): tube tester
 
 
For the majority of users, there is hardly the need for a universal tube tester. What they require most is kind of  
simulator approximating the amps in use. That tester then serves to help them to make the best out of the tubes they have.  
 
limage
11-09-14
15:37:51
回覆 (265): tube tester
I like to be the first one in the queue!  
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answers pls.
drwkng
11-09-14
15:32:15
回覆 (264): tube tester
a diy type tester  
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I like to be the first one in the queue!
bobui
11-09-14
15:28:32
回覆 (263): tube tester
i'm thinking of doing a tube tester for the peking road in mates. this is a diy type tester. so i just want to ask a few questions  
 
1. what is the absolute minimum tubes type you can live with?  
2. what is the minimum type of functions you can live with?  
3. what is the price range of the tube tester is acceptable?
drwkng
11-09-14
15:02:32
回覆 (262): Matching Valves
i don't think that is not how gm is defined. i think gm=di(a)/dv(g)  
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Oh yes, that was a bit misleading. The slope of the grid characteristic, is called the mutual conductance gm. The mu (μ) of a valve is its amplification factor. When measuring or compare the input AC with the output AC, it only and simply reflects the mu (μ) factor ast most. Neverthless, its one good way to measure the variations of two or more output valves for a given operating conditions.  
 
Can I make you talk more please!  
bobui
11-09-14
14:41:57
回覆 (262): Matching Valves
 
Now I can make you talk!  
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that's simple. i only need a glass of wine.
drwkng
11-09-14
14:38:05
回覆 (261): Matching Valves
since there is only one grid, you can't use the two sections independently.  
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Yes, that was a bit misleading. To make it clear, the two cathode are speerate and can be connected in series or parallel to operate either as a single cathode or double. And when double, you increase the max pa. from 350ma to 600ma or 45W to 60W.  
The answer remain that when connect the two cathodes in series 12.6V, the current is 3.3A  
 
Now I can make you talk!  
 
bobui
11-09-14
14:21:02
回覆 (260): Matching Valves
Oh, a reminder; 6C33C cathode connect in series is 12.6 V, 3.3A. If connect in parallel, the voltage is 6.3V, 6.6A. 6C33C has two seperate cathodes for each section of the anode. For SE, the two sections would be conncected togther!  
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since there is only one grid, you can't use the two sections independently. you can either use one or both sections.
drwkng
11-09-14
13:57:12
回覆 (260): Matching Valves
Connect a signal Gen. to the grid of the valve and measure the AC output level from your speaker terminal. Important thing is to make sure you have a dummy resistor connected instead of your speaker. And if you want to measure the AC signal balance between the two channels, simply repeat this process by applying the Signal Gen to the input RCA and measure the AC level at speaker terminal.  
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i don't think that is not how gm is defined. i think gm=di(a)/dv(g).
drwkng
11-09-14
13:53:33
回覆 (259): Matching Valves
For matching uncommon valves that are growing in popularity in audio such as 6C33C or Svetlana 811-3, I would either use my home made valve tester or simply plug in the amp and measure the dc as well as AC working conidtions.  
 
After all, the two main fuctions of nearly all valve testers are to give you measurement of the Cathode mA for a given bais and gm which is all you need to know for matching audio valves.  
 
For gm measure:  
1. Connect a signal Gen. to the grid of the valve and measure the AC output level from your speaker terminal. Important thing is to make sure you have a dummy resistor connected instead of your speaker. And if you want to measure the AC signal balance between the two channels, simply repeat this process by applying the Signal Gen to the input RCA and measure the AC level at speaker terminal.  
 
You can actually measure the falling frequency output by turning the frequency to 20kHz and measure the output level and compare if the signal is at let say 1kHz.  
 
You will be amazed what a Signal Gen and a good voltage meter can tell you!  
 
Good luck!  
 
Oh, a reminder; 6C33C cathode connect in series is 12.6 V, 3.3A. If connect in parallel, the voltage is 6.3V, 6.6A. 6C33C has two seperate cathodes for each section of the anode. For SE, the two sections would be conncected togther!  
 
bobui
11-09-14
13:42:31
回覆 (258): spot welded數码線
CP, 呢部似喇!
Derek2A3
11-09-02
10:27:51
回覆 (257): spot welded數码線
have some headphone cable which might also be worth a try  
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Try! let me know when you are ready
Derek2A3
11-09-02
10:25:03
回覆 (258): spot welded數码線
類似Derek兄的牙科點焊机:
cpyip
11-09-02
10:24:52
回覆 (257): spot welded數码線
類似Derek兄的牙科點焊机:
cpyip
11-09-02
10:22:15
回覆 (256): spot welded數码線
I have some headphone cable which might also be worth a try !
daiwok
11-09-02
09:55:23
回覆 (255): spot welded數码線
葉兄, 謝謝資料o  
 
相中碰焊機之尖咀鉗與碳刷體積不少, 相信難成功焊接訊號線o 當然只從相片和文字推斷如何操作, 不能作準o
Derek2A3
11-09-02
09:47:55
回覆 (254): spot welded數码線
Derek兄  
淘宝有一種機叫:"碰焊机,熔焊机,可取代电烙铁,铜线焊接好帮手 "  
是否可以代替點焊?下是其操作,我還未完全明白。  
 
 
 
碰焊机使用方法;1把接有尖咀钳和碳刷的两面三刀根导线分别接在碰焊机后面的接柱上  
2把尖咀钳钳住要焊的两根导线 在尖咀钳钳住的地方要把线漆皮去掉,让尖咀氏与两根  
导线导通,调节适当电流,电流调节与焊接导线粗细有关,线粗焊接电流大 把焊接的两  
根导线剪齐,把碰焊机接有碳刷的头碰两根要焊的导线,使之发出电弧。使两根导线熔焊在一起,线头成球型,焊接就OK  
注意事项;焊接时但要注意焊头一碰要离开一点点距离使之发弧,否则就不能焊接。如果  
两个碰头在一起,就不会发弧,还会损坏设备,这同电焊机焊接时一样
cpyip
11-09-02
08:43:44
回覆 (253): spot welded數码線
Oh, this is the condom-less approach!! It must be very transparent and dynamic!
icefox
11-09-01
17:30:15
回覆 (254): spot welded數码線
這種機,淘宝賣不用400人仔。
cpyip
11-09-01
17:00:27
回覆 (253): spot welded數码線
my own shiny cartridge .......  
 
Photobucket
daiwok
11-09-01
15:59:41
回覆 (252): spot welded數码線
I think we can do better than this ..... rather than solder direct, spot weld direct. This is actually Frank Schroders very own tonearm which is not for commercial sale. The shiny body looks familiar 8^)
daiwok
11-09-01
15:30:50
回覆 (251): spot welded數码線
試了一下:  
這條外貌一般,但出來的聲音,真不是一般!  
看來spot welded工藝,在這里也奏效的。
cpyip
11-09-01
11:55:30
回覆 (252): spot welded tube pins
The Telfon jacket is fine, not even a single scratch.  
 
If you choose the right duration & power setting, even those plastic insulators in flimsy RCA connectors can survive happily.
Derek2A3
11-09-01
10:13:04
回覆 (251): spot welded tube pins
 
Derek,  
 
Did it hurt the white Teflon jacket?  
 
limage
11-09-01
09:53:18
回覆 (250): spot welded tube pins
CP兄, 最緊要你鍾意!  
 
 
哇,咁咪好堅!!!  
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睇多張相先講啦
Derek2A3
11-09-01
00:20:44
回覆 (249): spot welded tube pins
Moment of truth!  
 
Believe it or not, spot welded tube pins don't need solder.  
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哇,咁咪好堅!!!
icefox
11-08-31
23:09:00
回覆 (248): spot welded tube pins
Moment of truth!  
 
Believe it or not, spot welded tube pins don't need solder.
Derek2A3
11-08-31
22:53:06
回覆 (247): spot welded tube pins
The pin & the wire welded together. I know that doesn't look good, patience pls
Derek2A3
11-08-31
22:48:28
回覆 (246): spot welded tube pins
From top to bottom: the welder probe, the wire, the pin, the other welder probe.  
 
apology on the picture quality, that's the best I can with what I have in hand
Derek2A3
11-08-31
22:45:58
回覆 (245): spot welded tube pins
The pin
Derek2A3
11-08-31
22:43:05
回覆 (244): spot welded tube pins
gauge 18 solid core wire
Derek2A3
11-08-31
22:41:40
回覆 (230): spot welded cables
Derek兄弄了條點焊過的RCA線給我試,听了近5小時,我第一个印象是此線分析力很高,樂器尾音可以表現出來,利害!  
今天弄牙時,我告訴Derek兄我的聽感,另外又满足我的好奇心,Derek兄又點焊了條數碼線給我試。  
這幾天有空會好好聽聽這不一般加工的線。
cpyip
11-08-31
22:40:15
回覆 (243): spot welded cables
 
 
…….before you can recover the cost of the welding tool?  
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Let me put it this way. If the welding tool has proven to work wonders on different kinds of connections, tube pins, electric, electronic or speaker cables, cartridges, tonearm connections and even computer hookups, the cost of this machine is nothing since all friends here may share this fruitful harvest.  
 
May be our Dr. Feikeung could find sexual applications too!  
 
 
limage
11-08-31
17:01:17