Showing posts with label Jensen. Show all posts
Showing posts with label Jensen. Show all posts

Thursday, February 27, 2014

Jensen Ultraflex redux

A few updates to the Jensen Ultraflex
Revised crossover + EQ/HF boost 
 The fixed resistor attenuator was inspired by the Jensen Duette crossover + recent knowledge gained in boosting frequencies above 7khz using an EQ network in my Altec 2-way XO experiments. Try it on your Heathkit SS1 or Eico HFS1 which AFAIK, used only a 2uf beeswax paper cap + L-pad.

Damping removed
paper in oil caps for
crossover and EQ
Happy Listening!

Saturday, May 26, 2012

Listening Room - Monaural Hi-Fi

Why mono?




The JEL SE2A3 and SE10 integrated mono amplifiers were built for this installation.


Idler driven turntables from Rek O Kut, Garrard, Presto, Bogen/Lenco, Neat and...


...viscous damped tone arms equipped with variable reluctance cartridges from GE > Tannoy.


Altec 802 + 416 drivers converted to field coil powered by a 12VDC power supply.





Jensen M10 field coil was featured in the 2009 November Hi-Fi Show.






another project....but just as significant ;)   







Monday, June 20, 2011

Jensen Ultraflex Cabinet for 8" Speaker

Today is the end of a long weekend commemorating the 150th birthday of our national hero Dr. Jose Rizal. I can't help but wonder whether he as well as our other national heroes died in vain... I am quite confident our current president is a sincere man who wants to get rid of corruption and lead us towards progress but there are elements in government as well as sectors in our society who don't cooperate. ;o( 

But mulling over matters beyond my control is a waste of time and energy. It's best to turn time and effort towards productivity. ;o) When I lived in the USA holidays were spent building projects to avoid heavy traffic and crowded places, so...

Years ago I wrote fondly about the Jensen Duettes as SE amp friendly budget speakers. I am not abreast with current pricing on these drivers and wonder if they still qualify as budget specials?



 Influenced by the article my buddy Rofiel collected a few Jensen and vintage Japanese drivers and wanted to try a bigger cabinet so I sent him the plans below. A few months later a pair of Ultraflex cabinets built from 1/2" phenolic plywood arrived at my doorstep.


Meanwhile these Ultraflex cabinets sat in a storage bin in the attic for over a year so a week ago I dropped by Joey's shop to cut holes on the front baffle with his router.


High quality plywood is expensive and hard to find in Manila. The closest affordable option we have available is phenolic faced plywood for industrial construction.



Simple crossover using a 2uf paper in oil cap + generic 16 ohm L-pad to the RP103 tweeter. 


Damping material for top and bottom panels as recommended on page 2 of the plan. Initially I was listening without any damping material and it was fine in free space standing on glass blocks. The moment I placed it in a corner, the bass tended to boom. Since there's no Walmart (my old source for Dacron) in Manila, I cut up an old foam pillow. That controlled the bass boom but I may have to experiment further with material and amount of damping...


Bogen B62 (Lenco L70) - stock arm fitted with a Pickering 380 or Shure M7D (coils connected in series) for Stereo LPs played in mono + Velvet Touch viscous damped tonearm with GE RPX---> JE Labs/PAS preamp - Telefunken 12AX7 phono + 12SN7 linestage (only one channel used)---> JE Labs SE71A amp.


Evolution of a mono hi-fi system in the study room...

Tuesday, February 15, 2011

November 2009 Hi-Fi Show

Mono minimalist
Cast of characters
Bessa R + CV Nokton 50/1.5
HP5+/Diafine
Lin - classic speaker guru par excellance and Rofiel - mono aficonado

Rofiel found this Jensen M10 field coil 13" driver (OEM WE TA4151 - more info) stashed in an ancient garage 120 kms. away from Manila
I revived the tube rectified  power supply with fresh Sprague ATOM capacitors. Since original replacement cones are unavailable, we took it to Lin for restoration.


The result of Lin's...
...painstaking labor.


To augment the top end, we added a phenolic diaphragm'ed Jensen RP103 alnico horn tweeter through a simple DIY crossover


Rofiel designed a Klangfilm inspired open baffle using phenolic plywood with piano hinged wings to maximize bass yet convenient transport.

Mono front end: Rek O Kut B12H 


Pickering 190 + GE RPX 78 stylus (left)

with variable EQ

JEL mono amps

Lin inspecting the installation of the Jensen M10
Bessa R + CV Nokton 50/1.5
HP5+/Diafine

...gazing on ancillaries 
Bessa R + CV Nokton 50/1.5
HP5+/Diafine

Bessa R + W-Komura 36/1.8
TX400/Difaine

Friends and Visitors

Bessa R + CV Nokton 50/1.5
TX400/Diafine

Bessa R + CV Nokton 50/1.5
HP5+/Diafine
Bessa R + CV Nokton 50/1.5
HP5+/Diafine

Bessa R + CV Nokton 50/1.5
HP5+/Diafine
Bessa R + CV Nokton 50/1.5
HP5+/Diafine
Bessa R + W-Komura 36/1.8
HP5+/Diafine


Me and the Bessa R...
...shooting film!

Thanks to Keith, Francis and Arnold for the digital captures!

See you at the next NHFS!