Fun with Lightbulbs and the SOZ...

[HIPCHECK]

from looking at your pictures i think this thread is getting very close to getting bumped......... to the ugly amp thread!

i am working on a couple of SOZ amps also, glad to see someone else building these amps

i had a SOZ built (with as many test clips as yours!)with some 12V halogens like another forum member tried , and it was a little too much for me. i decided to go all out with big sinks, dale rh-50's, and irfp260n- prolly a LC power supply.

happy building!

 

[opc]

Hi Guys,

Hipcheck: it's good to hear from another builder on here. You're right about the ugly amplifier, but this is one case when you can't judge a book by its cover. After dealing with the Aleph 2's and this amplifier, I applaud your effort to actually heatsink the resistors. Even at 10 watts this thing produces an incredible amount of heat, it's like it never ends. Even the large heatsink I have on the bridge rectifier is burning hot. To get 50 watts out of the SOZ you'd need a chassis the size of the Aleph 2's just to keep the mosfets under control. Keep me posted on your progress, and just for fun, what sort of power output are you aiming for?

I had a quick question for Nelson or anyone else who would know. Could you build a SOZ with 32 ohm resistors in place of the 8 ohm, and 4 ohm in place of the 1 ohm to drive a pair of 32 ohm headphones? It would fall somewhere between to BZLS and the SOZ. With higher resistor values it would be possible to build the whole thing on a smaller heatsink, and still have a mini-SOZ just for headphones. Any comments on this would be great.

Cheers,
Owen

 

[lineup]

Thanks for the feedback!
----------------
Dennis: Those bulbs are Phillips Clear 300W and I got them at Home Depot for about $3.60 CAD each. Once they heat up, two bulbs in parallel give about 10.5 ohms, so I really need to place another 100W - 200W bulb in parallel with the existing two to get down to 8 ohms.
Lineup: I love the layout! Looks just like my little ST-70. It's funny, the glow from the bulbs is almost appropriate give how close this thing sounds to a tube amp when you run it with a SE input.
----------------------
Anyhow, thanks for the tips, it's always fun to toss some junk together and have it work so well the first time you plug it in.
Cheers,Owen

Actually is not very much New Under The Sun 🙂
My friend Tyimo
informed me about this Lighting Pre Amplifier:

thanks Tyimo
I go have a look at that link/amplifier
----------------------------------------------------------------
edit:
This is the correct Tyimo link
Pass Labs > the enlightened bride of zen
http://www.diyaudio.com/forums/showthread.php?s=&threadid=37323
.

lineup

 

[Nelson Pass]

Originally posted by opc I had a quick question for Nelson or anyone else who would know. Could you build a SOZ with 32 ohm resistors in place of the 8 ohm, and 4 ohm in place of the 1 ohm to drive a pair of 32 ohm headphones?

Of course. You might also consider some smaller devices like
IRF610's, just for grins.

😎

 

[GRollins]

You'll need to make some accomodation for a common ground.

Grey

 

[lineup]

You might also consider some smaller devices like
IRF610's, just for grins.
😎

http://www.passdiy.com/pdf/balzenpre.pdf
See balzenpre amp circuit in my attachment.

Sennnheiser's Hi-Fi topmodels of Headphones have a high impedance.
My brother, on my recommendation bought Sennheiser 600
Has got Z= 300 Ohm impedance

Nelson tells you to use IRF610, which are better for lower power!
This is actually the devices Balanced ZEN Preamplifiers use.
The working currents, 40 mA across 750 Ohm at 60 Volt supply,
is an excellent match for 300/600 Ohm.
I would stick out my nose out here:
😎 This 60 Volt DC amplifier would even feed most 32 Ohm Headphones
with very good results.

🙂 Final lineup verdict:
With no or very little change,
you may use Balanced Zen Pre as a very good headphone amplfier.
Face it:
If it is good enough for a balanced preamplifier!!! it is too good for headphones.

Balanced Zen Line Stage http://www.passdiy.com/pdf/balzenpre.pdf
Copyright 1997 Nelson Pass

 

[Variac]

You'll need to make some accomodation for a common ground.

Or rewire your 'phones. Some have detachable cables at each earpiece- those are easy!

The headroom people sell the cables but at quite a cost

 

[HIPCHECK]

iIhad been thinking of a SOZ source follower (posted by GRollins in the SOZ with current source thread) as a headphone amp. I have several irf610/dale rh-50 7.5ohms to use up in a project!

http://www.diyaudio.com/forums/attachment.php?s=&postid=258012&stamp=1067564059

i had liked the szekeres amps i had built which led me to try the SOZ as follower. the test rig i built was HOT for sure, and sounded pretty good.


I would need to convert SE to balanced and thought about trying out the ths4131/opa1632 from the twistedX/susygainclone thread. right now i have drv134 to convert to balanced, although i have seen mostly negative remarks for the drv134 in this type of application?

just curious would the buffered SOZ follower(?) or the discussed design of 32ohms to drive headphones be a better headphone amp?


here is a peak at the sinks for my SOZ amp I have IRFP260N as my mosfets and these hunks of metal to cool them!!

 

[HIPCHECK]

and another shot

i dont have it handy to measure but i think its about 12Lx5Wx7H or something? in that ballpark.

 

[HIPCHECK]

here is a shot of yet another junk yard amp. soz follower with irf610, dale 7.5R rh-50 and a $5.00 dollar toroid from parts express. this is what i was thinking of as a headphone amp.

OWEN any progress on your amp yet? if its still thrown out across the floor we all will understand 😉 but the house cat/dog might not