TREX and TREX2 Transistor regulator kit

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TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Wed Oct 15, 2008 9:36 pm

TREX is replacing the original simple zener regulator kit. The same regulator circuit can be built on the TREX PCB with the added features better smoothing and soft start and the option of using a zener diode or when run from a regulated rail like our 48v SMPS a 20k 25 turn trim pot can be used instead of the zener to give a adjustable voltage from 1.5v to 30v.
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TREX2 is a dual version of the TREX with 2 adjustable voltage rails.
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conleycd
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Re: TREX and TREX2 Transistor regulator kit

Postby conleycd » Fri Jan 09, 2009 8:19 am

These look helpful. How much are they going to cost Joe (for a kit)?

Thanks.

CC

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Tue Jan 20, 2009 9:48 pm

They are selling at the moment for
TREX $20AUD
TREX2 $30AUD

JLM online web shop is finally approaching its launch in feb 2009. There will be some increases in price on severel kits and products around that time due to the aussie dollar drop and the fact we haven't had a price rise in 8 years :shock:
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Re: TREX and TREX2 Transistor regulator kit

Postby janczmok » Fri Aug 26, 2011 10:42 am

Short one: If i need a +25V and -25V can i modify the TREX to get this values (probably with another TIPxxx transistor). I need those +/-25V for WBS rack ...

Thanks for any hints/infos.

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Sat Aug 27, 2011 10:21 am

janczmok wrote:Short one: If i need a +25V and -25V can i modify the TREX to get this values (probably with another TIPxxx transistor). I need those +/-25V for WBS rack ...

Thanks for any hints/infos.

You can build a negative TREX or TREX2 by reversing all the caps and zener if fitted and use a PNP TIP126 instead of the NPN TIP122. But you cannot get a + and - rail at the same time out of the TREX2.
Most WBS gear wastes the +/-25v down to 2 x 18v zeners in the module to make +/-18v so can be easily powered by a 48v SMPS and nothing else. Or you can use our AC/DC kit with power transformer.
Send me the circuit for the WBS device you want to power by email and I can show you how to power it.
Joe :-)

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Sun Sep 04, 2011 9:34 am

Most small WBS modules have a simpler resistor and 2 x 18v power supply and need no modifying but the larger modules with the extra transistor stage need R118 removed and 2 x 18v zeners fitted to work direct of the 48v SMPS.

Image

Most small WBS modules have a simpler resistor and 2 x 18v power supply and need no modifying but the larger modules with the extra transistor stage need R118 removed and 2 x 18v zeners fitted to work direct of the 48v SMPS.
Joe :-)

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janczmok
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Re: TREX and TREX2 Transistor regulator kit

Postby janczmok » Tue Sep 06, 2011 4:10 am

Thanks for the info. I've implemented it and now got a fully blown two channel racking :-) It's working perfectly, thanks for the good tip + advice. NO noise or hum at all.

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Tue Sep 06, 2011 7:42 am

janczmok wrote:Thanks for the info. I've implemented it and now got a fully blown two channel racking :-) It's working perfectly, thanks for the good tip + advice. NO noise or hum at all.

Cool good to hear you got it to work :-) yes it makes powering WBS modules very easy and with minimal cost and no hum or noise problems.
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janczmok
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Re: TREX and TREX2 Transistor regulator kit

Postby janczmok » Tue Sep 06, 2011 10:21 am

Actually, i finished the M1 outputs and i got Hum on my Firewire (e.g. M1 Mixbus output from the WBS), but that's just solely related to the WBS, which i will address. It's more or less symmetric vs. non-symmetric. from the PSU side, this is by far the best solution :-)

Thanks again for any help. I'll post photos when i'm completely finished.

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Tue Sep 06, 2011 11:23 am

janczmok wrote:Actually, i finished the M1 outputs and i got Hum on my Firewire (e.g. M1 Mixbus output from the WBS), but that's just solely related to the WBS, which i will address. It's more or less symmetric vs. non-symmetric. from the PSU side, this is by far the best solution :-)

Thanks again for any help. I'll post photos when i'm completely finished.

Probably worth connecting 20 to 22 so the virtual audio 0v is at the same potential as chassis and make sure all pin 1 XLR in and outs are connected to this point as well.
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mylesgm
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Re: TREX and TREX2 Transistor regulator kit

Postby mylesgm » Sun Sep 25, 2011 12:09 pm

Racking a neve kelso mic pre and a 3405 module. Should I use a zener or the trim build for that? M

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Mon Sep 26, 2011 8:18 am

mylesgm wrote:Racking a neve kelso mic pre and a 3405 module. Should I use a zener or the trim build for that? M

HI Myles
The trim pot can only be used if running from a 48v SMPS but is good because you can adjust 24v exactly. But if running from a unreg rail you have to use the zener diode.
Joe :-)

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mylesgm
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Re: TREX and TREX2 Transistor regulator kit

Postby mylesgm » Tue Jan 24, 2012 4:18 pm

Well finally got around to hooking up the kelso and I've a small problem. The trex powers the modules fine and they work perfect with a dynamic mic but there's a problem with phantom. I'm using the 48vdc switchmode power supply and have connected the 48v rail through a pair of 6k8 resistors with a 10uf 63v cap to ground which is my usual phantom circuit. With this switched in the 48v rail drops to 38-40vdc and there is a 500hz buzz with associated upper harmonics. When I switch off the phantom the mic sounds perfect whilst the mic slowly discharges the 48v so I'm assuming there is an issue with the implementation of the phantom circuit. Thoughts?

M

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Re: TREX and TREX2 Transistor regulator kit

Postby Joe Malone » Tue Jan 24, 2012 5:35 pm

mylesgm wrote:Well finally got around to hooking up the kelso and I've a small problem. The trex powers the modules fine and they work perfect with a dynamic mic but there's a problem with phantom. I'm using the 48vdc switchmode power supply and have connected the 48v rail through a pair of 6k8 resistors with a 10uf 63v cap to ground which is my usual phantom circuit. With this switched in the 48v rail drops to 38-40vdc and there is a 500hz buzz with associated upper harmonics. When I switch off the phantom the mic sounds perfect whilst the mic slowly discharges the 48v so I'm assuming there is an issue with the implementation of the phantom circuit. Thoughts?

M


Is the 10uF cap correct way around polarity wise?
Also with the 48v add a 470R in series with the 48v to the join of the 10uF cap and 6k8 resistor so it is super smooth. Without that 470R the 10uF can do little to clean the power rail ready for the phantom resistors.

What voltages are at pin 2 and pin 3 of the input XLR measured to pin 1 0v with phantom on with no mic? and mic?
Does the main 48v drop with no phantom mic plugged in?

Do you have a input circuit for the kelso you have as that would help.
Joe :-)

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mylesgm
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Re: TREX and TREX2 Transistor regulator kit

Postby mylesgm » Tue Jan 24, 2012 5:45 pm

Thanks I'll try that and I'll get back to you.

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