2013年4月25日 星期四

貫古通今的聲音---喇吧

Listen to Historic Speakers - from 1924 to 1944 - Part 1



Listen to Historic Speakers - from 1924 to 1944 - Part 2

2013年4月22日 星期一

Mission impossible ------- Plasma Mid (Plasma 555) 離子中音


不可能完成的任務................. Plasma 555 離子中音


Ike Quebec
Heavy Soul [RVG Edition]
Plasma 555 playing only (driver VT4C-211), no Tweeter no Woofer.
250hz~4khz.



Ike Quebec
Heavy Soul [RVG Edition]
05 The Man I Love

2013年4月19日 星期五

讓西電 L9 的恐怖低音更恐怖.....哪裡掉的哪裡找回來


能DIY...拿烙鐵的..參考看看!


模擬後Mrak 30hz.


向量 mark 30hz close speaker Fs.


有沒發現喇叭內的 coil  10Hz~1kHz的連續阻抗線上藍色與另分音線路下紅色線剛好相反mirror.
加起來也就阻抗是共軛matching......醬發現人家30hz 凸很高.......我們也能凸很高.
這就是建議的 .......哪裡掉的哪裡找回來.......否則別的暴力方法是容易多個香爐多個鬼.


模擬後Mrak 80hz. 40~80Hz也補上了.



向量 mark 80hz ..

2013年4月18日 星期四

有錢沒錢, 買個WE (西電)好過年-----西電 L9 的恐怖低音



有錢沒錢, 買個WE (西電)好過年-----西電 L9 的恐怖低音



1948 Western Electric L9 loudspeakers

Authentic 1948 Western Electric L9 loudspeakers in action at 2010 High End Show in Munich,
Germany. The music in the video is from Friedrich Gulda's LP "As You Like It",
on BASF (courtesy of Mr. Joe Roberts and Frank Schroder ).
連鋼琴踏板都很大聲.
Play Friedrich Gulda's LP "As You Like It"


以上有CD.....台灣沒賣
但可買 .....

Jazz Club - Swinging Jazz Piano  搖擺琴聲
01.Billy Taylor - La Petite Mambo
02. Tete Montoliu - Speak Low
03. Monty Alexander - Blue Alexander
04. Friedrich Gulda - Blues For H.G.
05. Milt Buckner - Glady's Dance
06. Francy Boland - Dark Eyes
07. Earl Hines - Second Balcony Jump
08. Oscar Peterson - Lulu's Back In Town
09. Eddie Thompson - How Could You Do A Thing Like That To Me
10. Eugen Cicero - Hello Dolly
11. George Shearing - Love Walked In
12. Paul Kuhn & Horst Jankowski - Honeysuckle Rose
13. Hank Jones - The Oregon Grinder
14. Red Garland - Daahoud
15. Hampton Hawes - I'm All Smiles


只是鋼琴踏板很小聲, 低音規模還是很恐怖.


2013年4月17日 星期三

Magic modify of converting cheap PP EL34 Amp's to 300B SE

Magic modify of converting cheap PP EL34 Amp's to 300B SE
              ------after all is dr. Klimo 300B circuit (OPT with Degauss coil inside )
Below  detail just usage one pole of P-P (push-pull)OPT coil to do  Degauss coil function.

hyper-link ....
http://www.audioasylum.com/cgi/t.mpl?f=tubediy&m=76018

Document...
I have now invested some time into this lark and a few things become clear.
If a typhical EL34 PP Amp is used with one EL34 as pure "Ballast" you can add your 300B on the other side.
The Impedance loading the 300B becomes 1/4 of the A-A impedance of the EL34 OPT. Typhically this will give between 1K - 1K5 nominalimpedance.
If we declare the 4 Ohm tap to be 8 Ohm and the 8 Ohm tap to be 16 Ohm we are fine(ish). If you need a < 8 Ohm output impedance you are nearly out of luck if your amp does not have 2 ohm Taps (few cheap chinese EL34 PP Amp's do). BUT, you can use a trick and connect your < 8R Speaker between the 4R & 8R Tap. This will give a tap with a very low nominal impedance, which would limit available power a little (which might explain thge rated 5W for the Beltaine).
BTW, I got a copy of the readers letter to CHF with the Beltaine schematic . Some interesting tricks. The EF184 driver pentode gets it's screen voltage from the 300B Cathode, 300B has LCL filtered DC heater. The EL34 uses an unbypassed cathode R and is indeed merely "ballast", balancing DC. The rest of the circuit is very traditional, EF184 drives 300B in classical Pentode driver, Triode output self biased circuitry .
So, converting any "surplus to requirements" cheap EL34 PP Amp to 300B SE in Klimo Beltaine style should be easy enough.

This is based on re-cycling a Dared Tube VP-80 which prooved way to unreliable for the guy who bought it.... Looks nice though:
Heaters for the 300B's will DC (probably LT1085-5 Reg) from the 6.3V Output Heaters and shared with the EL34 which will run AC.
The 6SN7's stage on AC, lifted to around 70V (in other words EL34 Cathode.
Some ideas are filched from Klimo (Screengrid/cascode upper grid bias, NFB switchable), some are mine.
To improve the way the DC magnetisation cancellation in the OPT tracks varying 300B's and to reduce differences between various EL34's the EL34 "Ballast" valve gets the Cathode voltage of the 300B as Gridvoltage, the cathode Resistor is suitably increased.
The Frontend uses a 6SN7 cascode to approximate a pentode, you can of course use a real pentode. The idea for me is to use only stuff I have "around" and good octal Pentodes are non too common in my stash.
The PSU substitues a Mosfet"Voltage Follower" for a choke, smaller (size is a premium).
Anyway, this should make an interesting little amp, gor for the usual WE Standard 7 - 7.5W....

In document we know Dared Tube main land China VP-80 clone already.

Principle ...
Old SE 300B connect high voltage on OPT coil cause  Hysteresis curve floating up (磁滯曲線飄起來) to O2 point.
Audio AC signal trasfer on the  Hysteresis curve then cause Audio AC signal  floating up too.
Meantime audio AC signal Loss signal sensivity and linearity (just partial saturation).


Here dr. Klimo 300B usage Degauss coil to pull back Hysteresis curve as below.
Driving Degauss  Tube as EL34 in circuit (as red line function).
If use Mosfet to replace EL34 then your need big heat sink(because always have DC current cross over Mosfet's D & S pole ).

Dr. Klimo is a  really master.

Sense of hearing
Old Tube amplifier always have good man-vocal  but woofer and tweeter seem  is  less a point .
But Dr. Klimo  circuit have something different just opposite.

The issue is cause tube ampifier RIAA play-bake curve have a drastic changes.

走過咖啡店早年歲月

咖啡店從無到有... 從有到無... 歲月的流逝 ,剩下的祇有記憶.

從無到有--- 舊店設立.
從有到無--- 拔營....牧咖啡的咖啡人.....移址, 啡客...........的遷徙.

咖啡店=咖啡+音樂

咖啡=日式咖啡+美式咖啡
日式咖啡=日式單品+日式花式咖啡
美式咖啡=美式單品+美式花式咖啡
.........."請不要找茶".

音樂=古典音樂+真空管