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回覆 (331): 無限障板扬声系统
kris
16-05-09
07:33:03
回覆 (330): 無限障板扬声系统
https://s.yimg.com/lo/api/res/1.2/sSmxuCgAYONMyBIvd5fS6g--/YXBwaWQ9eW15O3E9NzU7dz02NDA7c209MTtpbD1wbGFuZQ--/http://media.zenfs.com/en_us/News/afp.com/440cca7909f4a48bcfee687078791177479e63f7.jpg
kris
16-05-09
07:32:47
回覆 (329): 無限障板扬声系统
好厉害
tantan
14-04-15
07:17:01
回覆 (1): DIY 自作派同好同學會
dd兄近來有什么大作?
cpyip
13-10-16
08:34:41
DIY 自作派同好同學會
所有關于音响自作自受的事物,都可在此發表。
dd845
13-10-09
22:46:23
回覆 (480): Too much of me talking?
Sir, for you!  
 
bobui
13-10-07
17:58:47
回覆 (479): Why LCR RIAA?
Some of the phono amps that implement LCR RIAA?  
 
Allnic  
Audionote  
Da Vinci Audio  
Ayon Audio  
Thomas Mayer  
Ypsilon  
Aurorasound  
 
Due to high cost for the LCR Transformer, expect to pay a big chuck of your hard earned cash for any one of the above. The more user friendly one is from Aurorasound.  
 
Its hard to beleive that big household names would follow the trend in the near future and even if they do, its likely to be limited to their top of the range model. But then, you never know! Good luck!
bobui
13-10-07
17:09:32
回覆 (478): Why LCR RIAA?
Rafal C is using Tango in his Thomas Meyer LCR Phono.  
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Have taste lor!  
 
I am rebuilding my LCR phono. As a very high hand in LP/Phono stuffs. Daiwok, please take mine to your den to test drive when its done.  
 
bobui
13-10-07
16:22:17
回覆 (477): Why LCR RIAA?
Here is internal structure of the Tango EQ-600 LCR RIAA. See the usual cap and resistor value? Nearly all other manufactuers follow Tango values.  
 
Usual practice is to place the LCR between two gain stages. As long as the gain stages have output impedance 600R or lower. That would be fine!  
 
bobui
13-10-07
16:18:57
回覆 (477): Why LCR RIAA?
Rafal C is using Tango in his Thomas Meyer LCR Phono.
daiwok
13-10-07
16:17:57
回覆 (476): Why LCR RIAA?
Allow me to clarify one thing pls.  
 
The RIAA emphasis is done at the studio recording/record process. The LCR RIAA transformer have been extensively used to match with the RIAA standard.  
 
The RIAA de-emphasis is done by yours and mine phono amps. To acheive the de-emphasis process, a LCR RIAA transformer in reverse mode is most accurate. Get it!  
 
Introducing the LCR RIAA transformer into a Phono circuit is to enable a more accurate RIAA de-emphasis curve.  
 
Your question may come to this!  
 
Is LCR RIAA transformer better sounding than commonly used feedback network made up by caps and resistors found in most phono amps?  
 
The answer is "more accurate".
bobui
13-10-07
15:59:22
回覆 (475): Why LCR RIAA?
Five to ten years ago, there were more than several manufactures offer LCR RIAA transformers for DIYers such as Sowter, Tango, Lundahl, Steven & Billington, Audio Consulting etc. Today, only a few of them are still active in the market but the funny thing is as transformer manufactures disappearing, there is a growing number of Hi-end component brands start adopting the idea of an LCR RIAA Phono amp. The newest on the list is the Korean brand, Allnic 3000 and 5000 series phono amps.  
 
So the question is Why LCR RIAA?  
The RIAA emphasis is a process necessary to reduce the ampliture of lower frequency and increase the higher ones for mechanical reasons ( or you would need to make the tonearm the size of your arm for the handling of the lower frequency and a cartridge bigger than your fingers to keep up with the vibrations)! And to acheive the required RIAA emphasis, coils, capacitors and resistors are needed to form a complex transformer network (LCR RIAA) and the difficult part is that tailor made values are a must. Taior made coils is a relatively easy task. Caps and resistors, you got to be kidding lor!  
 
The work for de-emphasis the RIAA is in the job of our much loved PHONO. And you can almost imagine the inaccuracy when throwing out the coils and only rely on off the shelves fixed value capacitors and resistors.  
 
Now you know why different phonos sound so different la!  
 
Change a valve most likely would bring a different output impedance and gain. This surely would affect the RIAA feedback loop which is commonly used in acheiving the RIAA de-emphasis.  
 
Below LCR RIAA from Audio Consulting for your consideration. Its only CHF3,460 for a pair. Thats roughly HK$28,000.-  
 
One of the very original LCR is from Tango. The EQ-600. Dont expect to pay much less if you got lucky from bay watch for a pair lor! I beleive Stevens & Billington still wind their own LCR at roughly 600 UK pounds.  
 
 
 
 
 
bobui
13-10-07
15:27:20
回覆 (474): Mono
the groove is so clear-cut between asymmetric modulations.  
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Oh Yes, the groove, so clear cut, wow, asymmetric. Oh yes!  
 
Here, this one taken from a different angle. The groove become a bit blur and not so clear cut now. Right? But still asymmetric!
bobui
13-09-26
11:47:40
回覆 (473): Mono
Beautiful, neat, ginger brown, sexy legs and has a kind of vintage look! I want one please!
bobui
13-09-26
11:34:58
回覆 (473): Mono
 
 
It cannot be mono bobui, since the groove is so clear-cut between asymmetric modulations.  
 
limage
13-09-26
11:30:37
回覆 (472): Mono
I was scratching my head all evening trying to figure out if it may be a mono cartridge in the picture below.  
 
Please take a closer look and let me know your thoughts.  
 
I think I a beginning to understand why so many high hands prefer mono lor!
bobui
13-09-26
10:51:05
回覆 (471): KT150
The 833 look like a 小露寶!  
 
bobui
13-09-25
14:37:57
回覆 (470): KT150
 
For big power, you need this! :-)  
 
thekong
13-09-25
14:26:47
回覆 (469): KT150
You right! Can see it much clearer with the two photos. The KT150 is a bit taller and fatter at the waist line but still, NOT BIG ENOUGH lor for it is 40% higher in power.  
 
If the KT88 or KT120 is let say 10cm tall, the KT150 should be at least 14cm lor! You know what mean!  
 
bobui
13-09-25
14:05:23
回覆 (469): KT150
Ok, the KT120 (far right) is only slightly bigger then the reissure GL KT88 (2nd left)  
 
thekong
13-09-25
14:02:54
回覆 (468): KT150
The KT150 looks way bigger. Actually, I am not sure where it was KT120 or KT88 in the other photo. If it was KT120, then it is already bigger than the KT88!  
 
thekong
13-09-25
13:45:52
回覆 (467): KT150
>WHY MAKE THEM SO TINY<  
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Let's take a look at these 2 photos  
 
thekong
13-09-25
13:43:35
回覆 (466): KT150
no amateur is going to start a DIY project to know how it sounds  
 
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Total agree and there just too little info from New Senors .  
 
After all, the KT150 look to be just a variant of the KT88 family. How different can it be lor!  
 
There certainly something incorrect with the KT150. Given that the power dissipation is near 40% higher than the original GEC KT88. WHY MAKE THEM SO TINY?  
 
Size matter lor! Take a deep breathe and blow the glass bulb bigger la!  
 
bobui
13-09-25
12:21:47
回覆 (465): KT150
Lucky you 2A3, I have a large UK cow just fit your requirement  
________________________________________________________  
 
You are the man. Next round is mine!  
 
Talking about this KT 150, unless there are plate curves & operational data, no amateur is going to start a DIY project to know how it sounds
Derek2A3
13-09-25
10:39:15
回覆 (464): KT150
Ah! Manage to find a bit more offical info on the KT150.  
 
Faliment current is 1.75A, 6.3V, gm is 12.6mA/V  
Original GEC is 1.6A, 6.3V, gm is 12mA/V  
 
Interelectrode capacitance is a bit on the high side at 20.5pf but it doesnt state clearly if it was measured as Triode or tetrode. And I can only suppose it Cg1 to Anode.  
 
Here is a link for the spec.  
 
http://www.pyndt.dk/Tung-Sol%20KT150%20Curves.pdf
bobui
13-09-24
17:44:00
回覆 (463): KT150
Lucky you 2A3, I have a large UK cow just fit your requirement.  
 
 
=================================================  
 
Here is the new KT150. Power dissipation is said to be 70Watts as oppose to 42Watts from an original GEC KT88. It has two side getters similar to the GEC. I can see extra number of fins on the anode and thats probably enable it to a higher dissipation  
 
No other data can be found yet.
bobui
13-09-24
17:31:22
回覆 (462): DET5
idle power trans with 200ma, approx 400V 2nd?  
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Probably! But may not be as powerful as 200ma.
bobui
13-09-23
12:49:21
回覆 (461): DET5
let me know if you fancy to have a go  
_____________________________________________  
 
Thanks for the kind offer, surely will when the time comes. Right now, having the 83, my ass shouldn't be itchy for quite some time.  
 
BTW, do you have any idle power trans with 200ma, approx 400V 2nd?
Derek2A3
13-09-23
12:23:29
回覆 (460): DET5
Since you are using a 4V filament for the rectifier, you can explore other NOS 4V tubes, shouldn't be too expensive.  
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Oh! Yes, 4V rectifier usually much more reasonable priced than their 5V sisters in the 2nd hand market as long as you dont go for the high power mesh plates from Deutschland.  
 
I stocked up some long before the boom, let me know if you fancy to have a go. All you have to do is to put a resistor in series with the faliment.  
 
bobui
13-09-23
11:57:54
回覆 (459): DET5
Of the several pairs of PX25, this DET5 is kind of special. On the glass bulb, its written with "Officine Radio Marconi-.....". Believe to be Italian Marconi. The golden sticker near the bottom has a date of 19/4/49.  
 
The box anode looking almost identical to a GEC PX25 but the getter is located at the bottom of the bulb in a large heavy ring shape circle around the base structure.  
 
Sound - not too different from the commonly seen light bulb shape GEC/Osram PX25.  
 
A banker friend came over to my den over the weekend for dinner and asked if he could take home the PX25 SE mono amps. I told him the amps are very affordable but he must also take away all four pairs of PX25s as complete package.  
 
"The Whole is greater than sum of its parts"
bobui
13-09-23
11:49:23
回覆 (458): Mazda PP5/400
Congratz, man! Since you are using a 4V filament for the rectifier, you can explore other NOS 4V tubes, shouldn't be too expensive.
Derek2A3
13-09-23
11:19:34
回覆 (457): Mazda PP5/400
Rectifier is the U18, similar to a U52/5U4G except the faliment is in 4V rather than the usual 5V. Vintage UK Vortexion power and choke. Output is a Tamura 2005/5k primary.  
 
bobui
13-09-23
11:03:44
回覆 (456): Mazda PP5/400
A single CV1343, similar to a 6J7 in spec driving a Mazda PP5/400 at roughly 400V / 60ma, given an output of roughly 6W to a Lowther PM7A 16ohms in Acousta original cabinet.  
 
Voice and vocal is magical. Best with chamber and piano works.
bobui
13-09-23
10:59:02
回覆 (455): Family
Family - all that matters to you most. Enjoy your moon cake!  
 
Appassionata  
 
 
bobui
13-09-19
19:01:46
回覆 (454): Happy Birthday to Limage
Much appreciated for always being the first at Yum Cha, 52 weeks non-stop, table and chairs all reserved and keeping the many of us on leashs!  
 
Thank you and wish you a happy birthday!  
 
bobui
13-09-03
19:43:13
回覆 (453): Friday la
Ha Ha Ha Ha Ha! Friday la, party time!  
 
 
This one you must play loud, very loud, extreme loud, awfully loud  
 
bobui
13-08-23
13:09:51
回覆 (452): Which one you like?
 
 
 
 
Her child like soft tone and less intense singing style is a best fit to the lyrics. A bit sad! Just the right mood and emotions, right?
bobui
13-08-08
13:04:07
回覆 (451): C59
No la, too expensive after all.  
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Something to share!  
 
Just posted something in the "art & leisure, Born to Ride PR1 Bicycle Club"
bobui
13-08-07
08:16:47
回覆 (450): C59
No la, too expensive after all.  
Western Electric 300B & RCA 845 better investment at current stand.  
However, if heath become challenged, owning dozen of WE300B will of no use lor ....  
I think I will wait until my son become a little bit bigger first, when he can ride a bicycle, then I would need one to follow him.
Cadiver
13-08-07
02:11:23
回覆 (449): C59
Go go go la! The C59 is a very well balanced bike. The one photo you uploaded below is a 2011 C59 with the old logo and not completely new. Not your size anyway, Cadiver.  
 
Buy in Hong Kong, price is at least 25% lower than in the US and 30% lower than in EU.  
 
If you interested in Bike, please pay regular visits in 1PK bike thread in art & leisure.
bobui
13-08-06
17:59:17