AC/DC & POWERSTATION KIT BUILD THREAD

[Joe Malone]

Thanks for your reply Joe.

Yes, I used your calculator to VA needs. I'm using a 15v 50VA transformer, as your calculator suggested I needed 41VA when I entered very overspec'd values. I'm getting a voltage dip even if I just plug in one 50mA draw pedal, but I used values of 600 and 700mA for the 12v and 9v taps, and 400ma for the 24v.

The AC volts should be taken as the highest DC voltage you can set on the output of a reg. So no dc rails above 15v unless you are using the 48v rail as the pump charge will give you 30v but only at about 100mA max.

I've done as you suggested and checked values at the AC points on the board, and also the caps 1000uF caps. The voltage is sagging at the AC points if I plug in a single pedal- from 16.42v to 16.28v when drawing about 300mA of current, and from 16.42v to 16.39v when about 50mA is drawn. I'm not sure if this is within reasonable amounts of if it should remain steady regardless.

Ok this sounds like you problem. The 15vac should be wired between 0v and one AC in unless you have done the neve mod shorting the negative rail. Wiring to both AC in with no 0v will not work and the power supply will drift all over the place as 0v has no reference so hence the regs have no reference. Nothing should reg and the power supply should not be wired this way. Wire the 15vac between 0v and one AC in and you will be able to regulate finally.

If you have 2 x 15vac wire them in series to make 30vac centre tap and put the centre tap to 0v and each each end of the 15vac winding to a AC in each. You should be able to measure 30vac between AC in then. the centre 2 wire colours in the diagram on thew side of the transformer go to 0v.

[alistair]

Thanks Joe. Yes, the 48v rail is set to double so I can get 24v.

The transformer is this model- http://www.altronics.com.au/index.asp?a ... m&id=M5015
It is currently wired with black and white going to 0v, and orange and red each going to an AC tab. I believe this is how you are suggesting to wire it, but I always thought this was called Split Secondary, not Series. Between 0v and AC I read 16.3v, between the two AC tabs I read 32.6v.

[Joe Malone]

Thanks Joe. Yes, the 48v rail is set to double so I can get 24v.

You can get 24v but not @ 400mA even with heatsinking. You may get it if you short out the 47R 1w resistor and mount the 48v reg on large heatsink or case but only maybe due to the pump charging.

The transformer is this model- http://www.altronics.com.au/index.asp?a ... m&id=M5015
It is currently wired with black and white going to 0v, and orange and red each going to an AC tab. I believe this is how you are suggesting to wire it, but I always thought this was called Split Secondary, not Series. Between 0v and AC I read 16.3v, between the two AC tabs I read 32.6v.

OK that is correct. Just before you said you had 16vac between AC ins not 32vac. When you say dip I am not sure what amount or where you mean? Best to give me the total AC in to 0v and unreg volts across the 1000uF 50v to the right of the PCB which should be around ACin = 16vac x 1.414 = 22.5vdc unreg across 1000uF 50v caps? If it is less than this then there is something wrong in the build or a short on a output. Otherwise without photo's of the PCB build and heatsinking and wiring I cannot say why you are having problems.

The biggest guitar pedal power supply I made for Silverchair had 30 x DC outputs of all sorts of voltages and polarity.

[jakobz]

Hi there, I am building an ac/dc (v3) but i screwed up and accidently connected the 0v from my power transformer (20v/1.25a) to the center terminal, which caused the 47r resistor and one of the 10uf electrolytic caps (the one closest to reg1) to pop after a few seconds. I ordered replacements for the 2 components that are obviously damaged, but should i expect some of the surrounding component to be damaged too?

[Joe Malone]

Hi there, I am building an ac/dc (v3) but i screwed up and accidently connected the 0v from my power transformer (20v/1.25a) to the center terminal, which caused the 47r resistor and one of the 10uf electrolytic caps (the one closest to reg1) to pop after a few seconds. I ordered replacements for the 2 components that are obviously damaged, but should i expect some of the surrounding component to be damaged too?

For the 10uF 63v cap to blown usually means that reg is dead. Only need to change the reg and any puffed or popped caps and burnt resistor.

[jakobz]

I suspected the reg was going to be replaced. Thanks alot for your fast response

[Grummy]

Hello. I'll start by stating my newbability. Not that my newb questions won't make it obvious. I'm trying to decide on a transformer for a Powerstation. If I can sort this out, I'll buy a Powerstation. My hope is to build and 8ch VPR 500 series unit. So roughly I need  +16, -16 each @ around 1.5A (1.1 actually but a bit of headroom would be good I've been told) and 48v. I figured if I get the Powerstation I'd be able to power a second 8ch VPR unit down the road. I'm considering slowly building a small modular 500series console based off of the new stuff jeff's coming out with over @ Classic API.

I've tried using your transformer calculator but am not sure what to drop into the first field, "highest AC in to 0v". Would I put 16v in there? Or should I type in the transformers series voltage output? or parallel? Or something else? 
Everythin else seems to make sense. 

Would a transformer with these specs be good enough?
120VA /30v @ 4A series/15v 8A parallel

Or is that over kill and would these specs do it for me? 
80VA /24v @3.33A /12v @ 6.66A

Thanks.
Aaron

[Joe Malone]

Hello. I'll start by stating my newbability. Not that my newb questions won't make it obvious. I'm trying to decide on a transformer for a Powerstation. If I can sort this out, I'll buy a Powerstation. My hope is to build and 8ch VPR 500 series unit. So roughly I need  +16, -16 each @ around 1.5A (1.1 actually but a bit of headroom would be good I've been told) and 48v. I figured if I get the Powerstation I'd be able to power a second 8ch VPR unit down the road. I'm considering slowly building a small modular 500series console based off of the new stuff jeff's coming out with over @ Classic API.

I've tried using your transformer calculator but am not sure what to drop into the first field, "highest AC in to 0v". Would I put 16v in there? Or should I type in the transformers series voltage output? or parallel? Or something else? 
Everythin else seems to make sense. 

Would a transformer with these specs be good enough?
120VA /30v @ 4A series/15v 8A parallel

Or is that over kill and would these specs do it for me? 
80VA /24v @3.33A /12v @ 6.66A

Thanks.
Aaron

2 x 18vac 80VA will give you enough for 1.5A at +/-16v. or use 2 x 18vac 160VA for 2 x 1.5A at +/-16v both with powerstation fitted with 6A bridge.

[Grummy]

Thanks Joe.

[G-Sun]

JLM AC/DC Ver. 4 kit

0.1uF bead cap / 1 x 0,1uF 50v mono:
I couldn't find it in the bag. However there was two blue ones with similar shape marked 104. Is this the one to use?

I didn't understand the 3-rail-concept. Wanted +-V1 +-V2 and +48V, bought the AC/DC kit, but understands it's the powerstation-kit I should have..

And I feel I need to understand those options about bridge a little more. Reading this thread will help I guess

[Joe Malone]

JLM AC/DC Ver. 4 kit

0.1uF bead cap / 1 x 0,1uF 50v mono:
I couldn't find it in the bag. However there was two blue ones with similar shape marked 104. Is this the one to use?

They are the mono caps 104 = 100nF = 0.1uF. (I noticed the latest kits were packed with 2 instead of one for some reason)

I didn't understand the 3-rail-concept. Wanted +-V1 +-V2 and +48V, bought the AC/DC kit, but understands it's the powerstation-kit I should have..

You need +/-V1 and +/-V2 only if they need to be different +/- voltages like +/-16v and +/-24v. You do not need separate +/-rails for stereo or more preamps etc that use the same +/- voltages.

And I feel I need to understand those options about bridge a little more. Reading this thread will help I guess

Nor sure what you mean above? But best to always give me the voltages you need and what they will be driving (preamps types? number off? etc) so I can suggest the correct power supply and power transformer setup.

[G-Sun]

Thanks Joe!

They are the mono caps 104 = 100nF = 0.1uF

Good Had no idea but to ask.

You need +/-V1 and +/-V2 only if they need to be different +/- voltages like +/-16v and +/-24v. You do not need separate +/-rails for stereo or more preamps etc that use the same +/- voltages.

I think I understand now. I'll order a powerstation (for a 2ch ssl9k + Harrison Ford Filter)
Edit: Ordered.

Nor sure what you mean above? But best to always give me the voltages you need and what they will be driving (preamps types? number off? etc) so I can suggest the correct power supply and power transformer setup.

Bridge: Maybe that's for the powerstation only (I see it comes with bridge option.)
Well, I've got a 230VAC / 50VA for 2ch ssl9k with balancing-board, JLM gobetween and 1 JLM Fet DI, and 2 ch Harrison Ford Filter. +-18V for the ssl (+-15V for one IC) and +-15V for the HFF.
I believe the current draw for the ssl9k is 240mA each. So, do I then fill inn 240mA for both + and - V1 in thge calculator, or is it 120mA?
Can you give me the current-draw for the JLM add-ons?

Thanks!

[Joe Malone]

Thanks Joe!

Bridge: Maybe that's for the powerstation only (I see it comes with bridge option.)
Well, I've got a 230VAC / 50VA for 2ch ssl9k with balancing-board, JLM gobetween and 1 JLM Fet DI, and 2 ch Harrison Ford Filter. +-18V for the ssl (+-15V for one IC) and +-15V for the HFF.
I believe the current draw for the ssl9k is 240mA each. So, do I then fill inn 240mA for both + and - V1 in thge calculator, or is it 120mA?
Can you give me the current-draw for the JLM add-ons?

Fet DI 20mA @ 48v
GO between 10mA @ 48v (including phantom power of mic)

What ac voltage are the power transformer secondaries?

[G-Sun]

Fet DI 20mA @ 48v
GO between 10mA @ 48v (including phantom power of mic)

Thanks!

What ac voltage are the power transformer secondaries?

Sorry 18VAC

[Joe Malone]

Fet DI 20mA @ 48v
GO between 10mA @ 48v (including phantom power of mic)

Thanks!

What ac voltage are the power transformer secondaries?

Sorry 18VAC

18vac is perfect for +/-18v rails and keeping the heat in the regulators down. The standing current for the SSL9k would only be about 60mA per rail based on a quick glance at the opamps used going to maybe double that on full output into 600hm load.