JISBOS - great headamp !

juma · 22nd April 2008, 10:00 PM

Almost a year ago I bought a pair of Sennheiser HD555 headphones (50 Ohms) and since then I've been searching for appropriate headamp. I've tried diamond buffer and about dozen usual topologies found here and at Headwize.com, but nothing really shined until I gave JISBOS (http://www.diamondstar.de/jisbos/jisbos_design.html ) a try.
Some people mentioned it here but no one really told us how good it is. The design is pretty explicit, it is very stable and it sounds extremely good. The amp is completely noiseless.
The end result is so good that I had to report it here, and I recommend it to anyone who is in search for a unity gain headamp - small power buffer.

Steinchen and Amb (from Headwize), thanks for this great headamp !

I changed an original schematic a bit (parts availability) and this is how it looks:

juma · 22nd April 2008, 10:03 PM

I've built it point-to point in the old network switch box.
Pic 1:

juma · 22nd April 2008, 10:11 PM

A close-up - yes, it looks untidy, but IMHO p2p is far superior to PCB (3D beats 2D any day in the week), at least in audio - it would be a real challenge to make a PC motherboard p2p

Zen Mod · 22nd April 2008, 10:28 PM

congrats !

with almost same topology - you can try scaled down Pass's F5 .

juma · 22nd April 2008, 11:05 PM

Quote:

Originally posted by Zen Mod
congrats !
with almost same topology - you can try scaled down Pass's F5 .

Thanks,
probably I'll do it, if it's unity gain stable; scaled-down F4 (IRF610/9610 on output, Iq=100mA) sounded a bit dull.
Also, F5 has higher OLG => stronger GNFB
JISBOS uses strong Source and Emitter degeneration to minimize GNFB.

Pozdrav !

nelsonvandal · 23rd April 2008, 06:19 AM

I've also made one of these point to point. I agree, it sounds better than any monolithic opamp based amp I've heard.

juma · 23rd April 2008, 04:05 PM

Yes nelsonvandal, I saw your posts here and on other forums, they've been very informative. What cans are you using now and what headamp ?
I remember that you were occupied with pocket - battery operated version of JISBOS?

juma · 25th April 2008, 06:34 PM

Finally, I found the time to finish the front plate and case work.
Here it is:

ekaerin · 25th April 2008, 06:54 PM

Hi,

Cool. Finally a network switch box with a useful circuit inside.

/ Mattias

Onvinyl · 26th April 2008, 10:02 AM

Hi Juma,
What's in front of you HP-amp? With a HD-650, I found a unity-gain amp (that followed both a riaa-amp or a CDP) wasn't sufficient. Switching back to loudspeakers would almost destroy them. Or my ears...
Rüdiger

22nd April 2008, 10:28 PM	#4
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	congrats ! with almost same topology - you can try scaled down Pass's F5 . __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

26th April 2008, 10:02 AM	#10
Onvinyl diyAudio Member Join Date: Aug 2002 Location: Germany	Hi Juma, What's in front of you HP-amp? With a HD-650, I found a unity-gain amp (that followed both a riaa-amp or a CDP) wasn't sufficient. Switching back to loudspeakers would almost destroy them. Or my ears... Rüdiger __________________ "I can feel what's going on inside a piece of electronic equipment. I have a sense that I know what's going on inside the transistors." Robert Moog

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Downscaling Zen v.9 for use as headamp	kenev	Pass Labs	34	12th April 2010 01:06 PM
MC headamp with opa	PTSOUNDLAB	Analog Line Level	1	11th January 2008 09:56 PM
DIY Headamp for Sennheiser-650?	vhrynchuk	Tubes / Valves	5	15th November 2006 07:09 PM
It's my AD815 headamp	Kochkurov Maxim	Chip Amps	16	11th May 2006 11:44 AM
FS Gainclone Great Chassis, Potted toroidal, great sound	PHilgeman	Swap Meet	4	2nd May 2006 01:20 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

23rd April 2008, 06:19 AM	#6
nelsonvandal diyAudio Member Join Date: Nov 2006	I've also made one of these point to point. I agree, it sounds better than any monolithic opamp based amp I've heard.

23rd April 2008, 04:05 PM	#7
juma diyAudio Member Join Date: Nov 2005 Location: Zemun	Yes nelsonvandal, I saw your posts here and on other forums, they've been very informative. What cans are you using now and what headamp ? I remember that you were occupied with pocket - battery operated version of JISBOS?

25th April 2008, 06:54 PM	#9
ekaerin diyAudio Member Join Date: Jun 2004 Location: Stockholm	Hi, Cool. Finally a network switch box with a useful circuit inside. / Mattias

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)