Modifying the Bride of Zen.

[pixie]

I'm not going to buy a new transformer for my Bride of Zen.
I have a 30V Transformer laying around.

So, 30V * sqrt(2) is 42V after the Bridge.

If I stack 4 10V zeners instead of 6 is that all I need to do? It looks that way to me.

I should get a clean 40V out of it.

Can anyone see any other parts that will need to change? Possibly increase the power rating on the pull up resistor? I wouldn't think so.

Thanks,
pixie

 

[vdi_nenna]

Bride of Zen Trans

The project calls for 30+30 trans at.5 amps.
The Avel equivalent is the D4007, which is a 30v-0-30v @ 0.5 amps.

The trans is connected in series.

The power supply is suppose to produce 86v and is regulated to 60v by the zeners.

If you have a 30 + 30 with more current capability, that's even better. I originally had a 6 amp 30+30 trans. in my BOZ and it sounded so awesome. I have what the article calls for now and it's not as warm and detailed as it was with the larger trans. I'm poppin' that puppy back in when I get the chance.

Good Luck!!

Vince

 

[pixie]

Amps.

I have amps to spare on this 15+15. It's 7.5A.

That's not the problem. The problem is, I don't want to spend another $60 on a 30+30 even at 1A.

So, given that I'm not going to get a larger transformer, what do I need to do to use mine?

Thanks,
pixie

 

[blmn]

Pixie,

I don´t know the circuit, but it seems you need a +/- 30V dc regulated power supply using an 15+15V transformer, right?

The transformer you said you had is big, but it appears doesn´t be a big problem for you.

Considering this, you can use diode voltage doubler circuits on both sides of the transformer´s secondary winding to achieve +/- 43V or more at the input of the regulator circuit.

It´s easy and any basic electronic handbook has the information you need to do this.

Be carefull about ripple and decoupling. Use the best filtering capacities as possible.

Regards

 

[vdi_nenna]

Supply Doubler.

Pix,

You can see how this is done in a Booklet from Radio Shack that costs about $3-$4. They have them in all their stores.
It's called Engineer's Mini-Handbook, Basic Semi-Conductor Circuits, by Forest M. Mims III. #276-5013a. There is a series of them. I have a few and come in handy from time to time.

You'll probably need a few diodes and caps, but that's about it. You may need to baypass the rectifier circuit on the board, but I'm not sure. Study the circuit and see what you need to do.

If you are in a rush, I can try to draw it up and I'll email it to you. Get back soon, because I won't be near a computer all weekend!

Late!

Vince

 

[pixie]

Doubler

http://www.kwarc.org/bulletin/99-04/tech_corner.htm

This is a circuit for a full-wave voltage doubler (or so).

So, this could work. I will need a couple more diodes and caps.

Would you use this? Is the Radio Shack one different? I probably have it laying around too. I'll have to dig deep to find it though.

Later,
pixie

 

[vdi_nenna]

Doubler

I don't think it's the same. You might want to dig up the RS booklet. The one in the RS book has 2 caps across the rectifier's output.

If you email me tonight, I'll draw it up and email it to you tomorrow.


Vince

[email protected]

[Edited by vdi_nenna on 02-15-2001 at 04:53 PM]

 

[promitheus]

The use a voltage doubler in the A40 amp in the passlabs site. Why don´t you read that. I think it has all the info.

 

[Hoffmeyer]

I`ve just simulated the circuit from http://www.kwarc...., and the U-output is : [U(tr)pp - (2xU(diode))], meaning if you have a transformer with 15V peak/30V pp you`ll get @28V out.
If the capacitors are 10.000uF, the diodes, with their anode to gnd, will have to handle @22Amp at start-up.
Good luck.

 

[McKajVah]

Simulation program

Hoffmeyer:

What program do you use to simulate the circuits?

-Kaj

 

[Hoffmeyer]

I`m using Orcad`s PSpice 9.1.
It`s the best I`ve come across so far.
You can get a Lite version of ver. 9.2 from http://www.orcad.com .

 

[pixie]

I looked at the A40. It looks like it uses two Full-wave bridge rectifiers to get +-V for two channels. So, you're telling me to use the -V as ground for my Bride? Then the ground for the Bride is not equal to earth ground? I only want one channel remember. This doesn't make sense.

Thanks,
pixie

 

[mg16]

Pixie.. Chuck your transformer..it won't work

30 volts with the sec. in series will give you about 42 volts total. The Mosfet draws 40 ma. The drain resistor is 1000 ohms. You will lose all 40 volts across the drain resistor. You need at least 20 volts across the mosfet. If you bias down to 20 ma., that would leave you 20 volts of swing, or + - 10 volts output voltage swing. I am not even sure if 20 ma. is enough to bias the mosfet "on". I would save your transformer for another project, and buy a 30+30 at 3 amps or more transformer. That is about the only change I made to the stock version, and it sounds fantastic. Its worth building it as Pass intended, but with more current capability in the supply.
mg16

 

[paulb]

Voltage doubler will work

There's no reason why a voltage doubler won't work. It was the A75, not the A40, that used it.
See http://www.passlabs.com/projects/a75_2_4.htm
and the following section for a description of voltage doublers.
Note the doubler is a half-wave rectifier, so you should probably double the filter cap sizes.