My Take on X-BOSOZ

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#942
TR8

Ha! Russ, that TR8 looks great!

Friend of mine out here has one. Funny story. He was at a red light one day and a tow-truck pulled up next to him and the driver recognized him, waved and said "see you next time."

He just waved and yes. And yes, he was towed many more times.

But truth is, yours looks much better.
 
#943
Russ White said:
Hah, you love to hate em. Lets just say around my house Lucas is a curse word. 😉
Click to expand...


I know the feeling; use to ride a '77 T140 Bonneville. Ik knew nothing about the mechanical part but everything about the electric system of that bike:bawling:

Anyway, a friend of mine bought the X-BoSoZ package and is very happy with it. He told me there is not a wiring scheme included (as in how to wire balanced and houw to wire unbalanced).
Is it anywhere in this topic? (sorry started reading from page 94 and I'm not in the mood to read all 95 pages... :whazzat: )
 
#945
Update

Latest is that I still have one channel putting out 0.4 volts and one putting out 4 volts. This is after replacing all the FETs on the low channel. Need to look elsewhere. Did get the 6 position switch worked out. Clockwise, CCW, minor detail. More head scratching tomorrow.
 
#946
I just connected my two power supplies and one I think is working fine, puting out -21.8 and +73.0 without load. But the other channel is -14.6 and + 82.1. I have two transformers, one 2x12 50 VA and one 2x60 100 VA feeding them.
Does anybody has any idea what could it be wrong with the second one?
 
#947
since the total change in potential is about the same, it would seem that there's no problem with the transformer, just a wiring problem, or that you've got your ground tied to two different points.

that may not be as much help as you'd hoped for ...

ryan
 
#951
Re: Update

hayenc said:
Latest is that I still have one channel putting out 0.4 volts and one putting out 4 volts. This is after replacing all the FETs on the low channel. Need to look elsewhere. Did get the 6 position switch worked out. Clockwise, CCW, minor detail. More head scratching tomorrow.
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Hayenc,
I had a similar problem with both channels putting out only 0.4 volts. Turns out I did a stupid mistake when soldering in resistors R1,2,6&7. For each resistor, there are two holes right next to each other on one side, and you have to use the right one- see picture of the PCB. Maybe this helps?
 
#952
I think I have it chased down. The 4 volts output was too much, and as usual, I was testing in single-ended mode. Turns out the zeners were shorted on that side where I had the bad FETs before, and the channel I thought was low was just fine.

It now sounds great, driving balanced out from DAC1 to balanced in on Aleph2's. Will let it burn for a while and take a break for some BBall.
 
#953
hayenc said:
I think I have it chased down. The 4 volts output was too much, and as usual, I was testing in single-ended mode. Turns out the zeners were shorted on that side where I had the bad FETs before, and the channel I thought was low was just fine.

It now sounds great, driving balanced out from DAC1 to balanced in on Aleph2's. Will let it burn for a while and take a break for some BBall.
Click to expand...


Great news Craig. Your had me completely stumped. 🙂
 
#954
Always the advantage to stereo. Two channels to compare. When I finally set up to match some new FETs as my stock was running out, I checked the ones I had recently pulled from the low channel and they all checked out good. First clue I was looking in the wrong place.

So the A-B between channels turned out the bad zeners on the other channel. Should have done the gain calculation in the first place to know the gain was unrealistic.

Only regrets are now having plenty of matched FETs and yesterday was our diy audio get together and I would have liked to have shown off the preamp. Next year.
 
#955
Here are my psu boards took me a hour. ( yes i took my time ) First pic is the parts baggies layed out on my work space. ( terrific job on the packaging and labeling Brian )


Pre-amp QUESTION

Should The package i got are all the values correct. ? for the main pre-amp I was reading some where on this thread that there was a resistor mistake ? i don't want to assemble it if there is a resistor that has to be changed. does any one know of this mistake / Error / Or is there even a mistake.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
#956
Hi Jason-

The resistor values you refer to are R5 on the preamp. The kits originally included a 221R value for R5 (based on Kari's schematic), but have been switched to 10K (based on MetalMan's schematic). You should have 10K R5s in your kit.

In fact, everyone who got a 221R in a kit shoudl have by now received a replacement 10K. If not, please let me know and I will get them out to you ASAP.

[EDIT] Thanks for the kind words!
 
#957
jleaman said:

Pre-amp QUESTION

Should The package i got are all the values correct. ? for the main pre-amp I was reading some where on this thread that there was a resistor mistake ? i don't want to assemble it if there is a resistor that has to be changed. does any one know of this mistake / Error / Or is there even a mistake.
Click to expand...


What do you have for R5? It should be 10K. Beside that everything is exactly as marked on the PCB.

The fact is the 221R resistor will work fine, just not with the high negative rail we are using with our power supply. The value of R5 is actually dependant and the negative rail.

For a 20-21V negative rail 10K works just great. You could go as low as 1.5K .25W without problems.

The confusion with the component value arose because of an initially much lower negative rail (9V).

I think Brian probably (in fact I am quite sure) sent you 10K.

Cheers!
Russ
 
#958
I bought the transformers from you same ones that you guys used. 🙂 small Donut's 😛 Ill start building it now. For those of you interested in my chassis here is a picture that i have attached.

thanks for the resistor help Brian/Russ.

Now to order your balanced volume pot / input switch.

An externally hosted image should be here but it was not working when we last tested it.
 
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