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icefox
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12-06-04
20:40:57
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| 回覆 (48): Naughty but Nice - The AVO |
You should have used that fund for an operation to sneak into Limage’s house and steal his AVO, together with the Keith Monk!
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I did want want to. I really did. I wanted to ask on the rib night if i could finally visit him and taste what a proper Maggie set up sound like. But then, I though, if i am going to make a fool of myself, i best not to do it in front of the ladies and surely not want to let the person sitting next to me to have the chance to laugh his teeth off lor!
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bobui
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12-06-04
18:25:04
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| 回覆 (47): Naughty but Nice - The AVO |
>Shit! I just made payment this afternoon and it aint cheap either<
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You should have used that fund for an operation to sneak into Limage’s house and steal his AVO, together with the Keith Monk!
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thekong
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12-06-04
18:17:14
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| 回覆 (46): Naughty but Nice - The AVO |
Don’t pollute the harbour LOR!
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Its already in very bad shape lor! And it was me who did it in the last 50 years lor!
Shit! I just made payment this afternoon and it aint cheap either |
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bobui
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12-06-04
18:11:10
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thekong
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12-06-04
18:06:40
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| 回覆 (44): Naughty but Nice - The AVO |
feed it to victoria harbour.LOR!
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Thats really heavy lor! I need a strong man!
Is it really that bad? Sure it is for some. But for the average guy wanted to get valve matching and general ideas on valve life such as gas leak, short, gm and cathode ma. Rubbish?
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bobui
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12-06-04
18:04:47
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drwkng
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12-06-04
17:57:59
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| 回覆 (42): Naughty but Nice - The AVO |
After many years of faithful service, my homemade valve tester finally came to a sudden sad end a few weeks back when i wrongly applied a too low grid negative voltage to a Svetlana 811-3 on test with a 811-10 setting. The cathode current rocket to the sky and turning the anode into bright red. This story taught me never watch the "The Good Wife" (on Pearl) when testing valve. The transformer gone smokey and gave up on me. It's time to move on.
"Man cannot be multi-task lor"!
Here is my new toy coming in about a week. Finally, i have a good enough reason to acquire one of the best that I have been long for. Any highhands want to share tips on the AVO and how to maintain it in top form. Please give me a shout. There is always room for improvement and when it comes to electronic equipment. I am in primary grade lor! |
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bobui
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12-06-04
17:48:46
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| 回覆 (41): Respectable DIY figure - etsang |
I find this thread very entertaining..... worthwhile to keep a record.
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Comment on fact is ok. Comment on people and motive is a never ending conversation and can easily turn into an arguement without one being noticed. Well, unless you want to be a politician!
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bobui
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12-06-01
13:22:05
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icefox
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12-06-01
12:15:45
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| 回覆 (63): Phono amp |
>I'll try it out over the weekend when the sonic performance of my system is more stable and hence far more revealing.<
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No hurry, take your time, you can have it as long as you want.
I think the DP still needs some more breakin anyway! :-)
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thekong
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12-05-29
16:19:56
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| 回覆 (62): Phono amp |
Oh yes, why not.
I'll try it out over the weekend when the sonic performance of my system is more stable and hence far more revealing.
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limage
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12-05-29
16:00:35
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| 回覆 (61): Phono amp |
>My secret weapon (which may not be spotted easily) lies in the Koetsu matching transformer that outclasses the stock one by margins that define day and night. <
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Ah, I forgot about that! Yes, that probably made the difference!
I still think the DP could match, or outperformed, the combo though. I just happened to have a latest DP on hand, should I send it to you on Sat? :-)
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thekong
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12-05-29
15:25:01
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| 回覆 (60): Phono amp |
power supply is a half wave voltage doubler
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This is one good example to show how outdated concepts can be used scrupulously in modern applications. We must not therefore dismiss anything just by eye-balling.
The EAR, by itself, is not going to beat anything. My secret weapon (which may not be spotted easily) lies in the Koetsu matching transformer that outclasses the stock one by margins that define day and night.
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limage
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12-05-29
14:21:49
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| 回覆 (59): Phono amp |
To be very honest, while limage’s system sounded spectacular with the EAR 834P, I have heard it in other systems with only so so performance when compared to other phono stages, including the DP.
I would be very surprise if the DP could not out perform the EAR in limage’s system. Of course, the DP phono, being a SS design, sounds less lush than the EAR!
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thekong
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12-05-29
12:48:26
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| 回覆 (58): Phono amp |
我估EAR可能會仲好聲。
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Look closely. You see that the power supply is a half wave voltage doubler. 我估if the B+ is running at around 250dcV, the power transformer secondary voltage need to be only at aoround 110AC. And I wouldnt be too surprise if the power transformer is orginally used as a small AC mains step down transformer.
And EAR managed to make it so nice sounding with a half wave rectifier! |
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bobui
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12-05-29
12:08:59
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| 回覆 (57): Phono amp |
| 咁好彩 Teresonic 老細用 fosgate phono amp (中間個塊) ，六枝膽，好好聲，我末見過EAR，我估EAR可能會仲好聲。Jim Fosgate咁出名，有錢唔怕買不過我無! |
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Cadiver
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12-05-28
17:17:42
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| 回覆 (56): filament voltage |
a lower than usual filamet voltgage is intentional
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Its true and it sound like cheating to me. Oh cheating can be goooooood, right?
The EAR, one of the best sounding phono I ever come across. you sure have taste!
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bobui
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12-05-27
20:08:56
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| 回覆 (55): filament voltage |
a lower than usual filamet voltgage is intentional
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Thanks so much for the enlightenment. Shameful or not, the EAR remains one of the best sounding phono amps, and at this price, it's a steal!
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limage
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12-05-27
13:32:06
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ThomasC2
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12-05-27
00:47:08
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| 回覆 (53): filament voltage |
"""""" Filament voltage remained a rather low 5.7V """"""
The use of a lower than usual filamet voltgage is intentional, a simple trick to reduce the tube noise of a phono amp commonly used in the ancient time when voltgage regulation is a luxury for domestic products. It should be a bit shameful to continue to use this method in these years.
Herebelow is the filament power supply section of the Fisher 500C receiver. |
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ThomasC2
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12-05-27
00:44:27
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| 回覆 (52): The Big Three |
JP Morgan, Merrill Lynch, Morgan Stanley, no lor!
Here is my true big three and a the very last one I just got it from the post today. Permeko, Partridge and Gardners. Got them all finally! Happy man! MC cartridge transformers.
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bobui
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12-05-25
22:42:57
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| 回覆 (51): Best of the best. Are we? |
音樂感
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Story time - Poor student first time
Long ago when I was young and foolish working as an intern in the housing council. I had a friend, a very poor chap from Manchester also as an intern with the British government, the NHS. We used to mixed milk with plenty of water in our weetabix (Kellogg cereal) and tea with no milk to save the penny for what we regarded as the "Essential for Life", Hi Fi lor! Day and night, we saved all our bus and tube fare money by cycle around town for work and leisure. Thats actually how I meet him (you know, racing to the next traffic light, winner get the scone). With the very limited resource for our first transistor intergrated amp project at the time. We went to the weekend ham radio carage sales in Camden to get some high current chokes to replace the need for some high value expensive capacitors. In those day, even the lowest priced 10,000uf, 50V cap would cost more than a few evening work at the local fish bar. For the driver stage, we simply omitted any voltage stabliser, we just didnt have the quid.
And to our surprise, that little ugly looking dog shit amp was so nice sounding. Very open and very easy to our ears. Of course, we didnt have a clue what was the magic behind. Less than a year later, we dismentle it and rebuild it with voltage stabliser, no more chokes and some new expensive 10,000uf caps. Then, we thought, transistor amp is so bloody awful. What the hell we want it for?
Now, I am old and ugly still working like a dog and cycle around the traffic lights in Hong Kong island. I am thinking, I really do miss my first ugly looking dog shit amp.
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bobui
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12-05-25
16:36:41
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Derek2A3
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12-05-25
15:01:18
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| 回覆 (53): Best of the best. Are we? |
究竟穩壓電路是否一定有好處
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Lower impedence is good, right? I think is all really down to each designer personal perference.
Here is my guide line.
The fact that I am a valve freak and prefer to maintain as many of my circuits in Class A1. The desire to have voltage stablise is a little "Less" essential. I say a little less because voltage stablise is not just about having a constant voltage despite current variations.
For power valve faliment voltage, stablise DC is still one of the most effective method to get rid of the 50Hz hum. A bigger problem when you are dealer with Lowther or if you were living in a very romote area such as Discovery bay!
And speaking of effective method, voltage stablise circuit is for most manufacturer, a very cost effective method to keep ripple under control. A choke is expensive and heavy, right?
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bobui
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12-05-25
11:06:47
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bobui
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12-05-25
10:37:14
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| 回覆 (51): Best of the best. Are we? |
For peanut indirect heat voltage amplication tube. I wouldn't give a damn about that 8 or 10% difference in heater voltage lor!
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that would depend on the tube type and the demand even for indirect tubes. so don't give a damn that so quick |
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drwkng
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12-05-25
10:28:12
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limage
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12-05-25
10:20:02
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| 回覆 (50): Best of the best. Are we? |
i don't think limage has to worry that much.
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For directly heat power tube, the faliment and cathode are in one and electron leaves the cathode with the condition that it must reach a certain temperature. Surely, exact voltage is the best but if i were forced to choose between a slightly below standard or slightly higher than standard heater voltage, I choose the later lor. Who cares about tube life?
For peanut indirect heat voltage amplication tube. I wouldn't give a damn about that 8 or 10% difference in heater voltage lor! |
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bobui
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12-05-25
10:09:59
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limage
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12-05-25
09:50:52
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| 回覆 (49): Best of the best. Are we? |
| i don't think limage has to worry that much. these are not power tubes. the lower voltage will cause the electron cloud to be less dense at the cathode. however the low current operation of these peanut tubes shouldn't be affected much. |
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drwkng
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12-05-25
09:42:54
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| 回覆 (48): Best of the best. Are we? |
唔好估喇, 俾個email 鬼佬 Tim 問吓啦o 燈絲電壓低咁多, 胆嘅spec 已經偏離正常, 點知 RIAA 是否已作配合o 若果有, 你攪正燈絲時, 平衡度會有問題o
而且, 電壓高左都可以話加大電阻值降低佢o 宜家係電壓低, 就算唔理noise, 飛走支 R16, 都未夠數, 要換牛o |
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Derek2A3
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12-05-25
08:09:17
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| 回覆 (47): Best of the best. Are we? |
This 834P claims an input voltage of 220 ̴ 240V and hence I assume it could be used without step-up.
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that is wishful thinking on tim's part. the filament is not regulated so it is at the mercy of the mains voltage. as you can see there is about 10% variation for 220-240.
Filament voltage remained a rather low 5.7V
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5.7? you mean 5.7x2. right? if that is the case, it is exactly 10% increase from 31V! |
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drwkng
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12-05-24
19:44:41
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| 回覆 (46): Best of the best. Are we? |
This 834P claims an input voltage of 220 ̴ 240V and hence I assume it could be used without step-up.
I did try to have the input voltage stepped up to 240V but it did not help much. Filament voltage remained a rather low 5.7V and the loss of sonic performance by going through two transformers did not of course justify the move.
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limage
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12-05-24
19:25:57
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cpyip
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12-05-24
18:42:17
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| 回覆 (44): Best of the best. Are we? |
檢查線路時，發覺次級低壓輸出30V。跟據常規，濾波後應有40V左右。但實際工作情况下，卻只量得31V，何解？
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if you look at the schematic, it says 240v primary. at your place, you only have 21x. that is about 10% drop already. |
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drwkng
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12-05-24
18:12:34
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| 回覆 (47): Best of the best. Are we? |
應在35V之內
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Mr Limage............Heater is in series connection. Meaning 12.6V X 3 = 37.9V. If the running dcV is down to only31, each heater is in roughly 10.33V which is about 16% below standard. Since different brand or make of tubes have unidentical current consumption. Best is to have the 33R in variable resistor. |
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bobui
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12-05-24
15:41:21
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bobui
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12-05-24
15:33:35
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limage
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12-05-24
15:26:19
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limage
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12-05-24
15:16:38
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