My Take on X-BOSOZ

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#1,081
Russ White said:
Hi,

Well I am very surpised you have any DC at all out of the XBOSOZ, the Output caps should not allow any. Not sure where to look there.

One word of advice, the XBOSOZ will sound better with the attenuator on output.

EDIT: One thing I would do is double check the soldering on the JT, you may have a relay power trace bridged to a signal trace. Go over it with your DMM to be sure the relay power pins and the signal pins are completely isolated. I know the joshua tree is a tight layout and it would be easy to have a solder bridge.

Cheers!
Russ
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Id like to know why you think that running the pre-amp with full signal into it is good but then shunting the output to a gnd/resistor ? Why would that be good ? I have never heard such a thing.
 
#1,082
jleaman said:



Id like to know why you think that running the pre-amp with full signal into it is good but then shunting the output to a gnd/resistor ? Why would that be good ? I have never heard such a thing.
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If you had read through the thread you would have seen the purpose described. 😉

One major reason it works very well is that it shunts the faint transistor noise to GND.

It wasn't my idea, and in fact I thought it was counter intuitive and tried the reverse first, but when I tried the attenuator on output I could see why it was recommended.

Cheers!
Russ
 
#1,083
Russ White said:



If you had read through the thread you would have seen the purpose described. 😉

One major reason it works very well is that it shunts the faint transistor noise to GND.

It wasn't my idea, and in fact I thought it was counter intuitive and tried the reverse first, but when I tried the attenuator on output I could see why it was recommended.

Cheers!
Russ
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Unfortunately i can't try it this way at this moment 🙁 i'll have to wait.

Any ideas for the future to use a remote / display for the volume output status ?

somehting like a pair of these to output a number..

An externally hosted image should be here but it was not working when we last tested it.
 
#1,084
Well I am not really sure where the dc from. It may be a grounding problem. I need to wait for the boss to finish the movie before I can start to check. I will go over the JT again, I don't think I bridged anything. One thing I did not anticipate is the relay noise. They are a lot louder than I thought. Great layout by the way. My father who has been a ee for 30 years was impressed.
 
#1,085
Well the Jt is fine. I get -.1 vdc on one chanel and If I hook it to a woofer it slowly moves back and forth. I also get 4Hz on that chanel with no signal. I only get the dc on the output of the power amp with the xbosoz powered on. Not on the output of the xbosoz.
 
#1,086
eapavant said:
Well the Jt is fine. I get -.1 vdc on one chanel and If I hook it to a woofer it slowly moves back and forth. I also get 4Hz on that chanel with no signal. I only get the dc on the output of the power amp with the xbosoz powered on. Not on the output of the xbosoz.
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Wow, not sure what to think. I will puzzle over it for a while, but maybe some of the more astute minds here can help out some more. BTW, thanks for the kind words earlier! 🙂

BTW how are you using the premp? Balanced out? or Single ended out? also are you doing single ended input?
 
#1,089
Ordered the boards/kits -- need suggestions on chassis and the rest

Hi All,

Great thread -- kudos to all. Just finished ordering a kit, and I need some (more) suggestions on the following in order to construct it:

Which is a good cost-effective Chassis?:
Wire:
Heat sink for the Pre-amp FET's:
  • Suggestions? Use Chassis body?
Volume Pots (Where I really need help!):
Rotary Selector Switch:
Connectors (rca/xlr)
  • Suggestions? One where to buy -- quality products only

Thanks -- any help/opinions would be appreciated -- my Klyne Audio Arts SK7 is broke, so I need to build a respectable replacement.
 
#1,091
Finished and burning in on the test bed, very happy with the results just need a good case to do this justice. Many thanks to all involved. An xbosoz and mini aleph together perfect.

Cheers Bruce
 

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#1,092
#1,093
Assesears said:
Finished and burning in on the test bed, very happy with the results just need a good case to do this justice. Many thanks to all involved. An xbosoz and mini aleph together perfect.

Cheers Bruce
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Nice work!!! Glad to see you did not seem to have much trouble.:up:

A nice combo indeed. I hope soon to have an Aleph or Balanced Zen to be fed from my XBoSoZ.

Cheers!
Russ
 
#1,095
Russ White said:


Jason,

I am glad you seem to have things well sorted out now and can sit back and enjoy the music. 🙂

Cheers!
Russ
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Not quiet yet 🙂 Now i have to build chassis and SMD mini A's.. Make some new cables, build a new chassis for the pre-amp and other project's. Then start my new dac project.
 
#1,096
I need help from all of ya junkyard runners with ugly looking and ugly working preamps........:devilr:

friend of mine bring me one little and sad preamp ,not 100% functional......
schematic and project background enclosed in attachment.....
now you know everything......
non profit pcbs and kits ......:cuss:


my question is simple: give me No. of post where is last valid (or actual-if you like) schmtc of your local "humpty dumpty super duper dear god how many acronyms in one name" preamp........hehe-meaning on X-Bosoz............
I want to remake this redundant preamp in something nice and workable (man-two CCSs in paralel!!!)
you all are bloody nutz......who can find anything in 100+ pages thread.......:clown: :devilr:
 

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#1,098
Russ White said:
Here you go.
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and here you go 😉


edit :

Russ -can you point me also for these :
value of Ref1 and Ref2 zenners ...just voltage-I'll calc dissipation 😉

value of D1 (or just give me current through CCS)

and-also-I presume that V+ is in range of +60 and V- in range of - 15 to 30V.....

waiting......😉
 

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#1,099
choky,

Nice bit of circuit you've got there, for a SE in to SE out. Make it fully balanced and it'll be pretty close to Nelson's UGS module.

For your questions, the REF1,2 are 10V, and we have been using the LM4040-10 precision references (they are much quieter than zeners). The CCS should target 80mA. Optimally V+ is 70V, but will work just fine with 60V. The V- can run as low as -9V, but I would not recommend coing any less than -20V (better stability and less noise from the CCS at higher negative rail values)

Cheers, Terry.
 
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