Post 1 says use the 100uF when employing the resistor. Do that first, and see if the voltage slide lessens.
I can not find this statement In post 1
also I got another hypno reg at +-30 V with sk170 6 - 10 mA Idss and huge heatsink and Is stable with 0.22 uF
also I got another hypno reg at +-30 V with sk170 6 - 10 mA Idss and huge heatsink and Is stable with 0.22 uF
You are right it only says about the don't do the leg trick if with the Blue. I must have wrote it somewhere else. I will edit it to be there too. Anyway there is 100uF designated position in Blue for when using a resistor. You need more uF to keep the impedance low as with leds only. Having another one made and no voltage slide is weird though. Same quality resistors and leds? Have never got such a slide reported in hypnos before. I would look its exactly the same made as the good regs, maybe some bad orientation of a fet or bjt, change the 2 leds, their jfet, such experiments.
thanks Salas for response
the other reg with stable V out got same type Leds and resistors
the difference Is jfets grade (Idss 6 - 10 mA) and huge heatsink
the other reg with stable V out got same type Leds and resistors
the difference Is jfets grade (Idss 6 - 10 mA) and huge heatsink
I have been asked to build an outboard psu for a preamp which requires a +- 24V supply, and was thinking of using a B1 Blue Hypno board as the basis. Would this arrangement be ok given that an umbilical will be required, or will it negate the advantages of the shunt reg ? There is only a small amount of space available in the pre for a couple of final caps.
Hello, I'm using the Hypno pcb as a +31V, -20.2V custom regulator and I noticed that after warming up the negative side goes to -21.2V which I found strange.
The negative AC voltage is 26V, the consumption is ~30mA and the dropper R has 34Ohms. The voltage dropper IRFP240 temperature goes up to 46centigrade and the shunt one to 35C. I'm using a trimmer to set the desired voltage as I need some flexibility in this.
Beside of this its working great.
Is this a normal behavior?
Thanks!
The negative AC voltage is 26V, the consumption is ~30mA and the dropper R has 34Ohms. The voltage dropper IRFP240 temperature goes up to 46centigrade and the shunt one to 35C. I'm using a trimmer to set the desired voltage as I need some flexibility in this.
Beside of this its working great.
Is this a normal behavior?
Thanks!
Trimmer has enough ppm, maybe only 0.25W also, jfet source heats up... set a bit lower initially so it goes where you like, but when warm. Maybe a fixed 1W film resistor can move a bit less, and/or a little sink for the jfet that runs the current of the trimmer. Its not abnormal I think, and if it has no consequence to the correct voltage bias of the served circuit, maybe you could not even mind. If its crucial, to have xxV right from the start and never different, use low noise Zeners like LM329.
What is it for?
Thanks! I will consider to change the trimmer to a fixed one and see how it behaves after and also check the jfet's temperature.
It's powering a SE JFet line amp. I made a plug-able daughter board over the place where the buffer should have been, so I can remove it anytime and modify it or test other line amp circuit. So for this reason I needed changeable voltages.
It's powering a SE JFet line amp. I made a plug-able daughter board over the place where the buffer should have been, so I can remove it anytime and modify it or test other line amp circuit. So for this reason I needed changeable voltages.
In general this hypno configuration stays good enough fixed if there isn't a too low Idss K170 there. The bit higher BL samples tend to have better tempco when run as they run in hypno, than the lower ones. Its also some trimmers are better than others and the couple of leds left there also help tempco of the Vref. Most multiturn don't do well with more than 2-3mA on the wiper, that is why I recommend a fixed resistor and a trim procedure of its value on post#1. Is the positive side made with a fixed one, and does it show some drift as the negative?
I'm using BL ones. I measured Idss between 6.3 - 7.5mA for all jfets used
I use 2 leds and the trimmer at the vref.
The positive one uses a trimmer as well but its voltage doesn't drift at all. I'm also using three other Salas v1.0 shunts with trimmer but on a different pcb and all of them have very stable vout.
This negative side has the highest voltage drop from 36V to 20.2V and this is the hottest (up to 50C on the first IRFP).
I use 2 leds and the trimmer at the vref.
The positive one uses a trimmer as well but its voltage doesn't drift at all. I'm also using three other Salas v1.0 shunts with trimmer but on a different pcb and all of them have very stable vout.
This negative side has the highest voltage drop from 36V to 20.2V and this is the hottest (up to 50C on the first IRFP).
Can be mainly heat related then. Can't you cut a bit of input voltage on RC pre-filter? But see about a fixed resistor also.
Salas Shunt Reg for Pearl 2.
Here are a couple of Pics for the power supply I made for the Pearl 2. This is using a prototype Blue Hot Rod version with 10,000uf filter caps, and panasonic FM 100uf caps, Dale CMF55 resistors, except for the VOut resistors, which are from parts bin.
+/- 23.87 rails.
Even I can do it!
Here are a couple of Pics for the power supply I made for the Pearl 2. This is using a prototype Blue Hot Rod version with 10,000uf filter caps, and panasonic FM 100uf caps, Dale CMF55 resistors, except for the VOut resistors, which are from parts bin.
+/- 23.87 rails.
Even I can do it!
Attachments
I need to go back and build a couple more of these - so I logged into mouser to order the same parts list again. Well, I was pretty shocked at how much teh prices for 240/9240 have risen!!!
So, we're in a recession!! Can't have that - so after some looking I found that schuro.de sell on ebay under the name diy-audio4you. Prices are good, and they have other handy bits like 3W metal resistors in low values for the shunts etc etc etc.
Link to them: Schuro Elektronik GmbH items - Get great deals on Knopfzellen, Lithium, Metalloxid MOX 3W 5 items on eBay Stores!
Usual disclaimers etc apply, not connected - and haven't even got the parts yet.
Fran
So, we're in a recession!! Can't have that - so after some looking I found that schuro.de sell on ebay under the name diy-audio4you. Prices are good, and they have other handy bits like 3W metal resistors in low values for the shunts etc etc etc.
Link to them: Schuro Elektronik GmbH items - Get great deals on Knopfzellen, Lithium, Metalloxid MOX 3W 5 items on eBay Stores!
Usual disclaimers etc apply, not connected - and haven't even got the parts yet.
Fran
I recently bought 9140, 9540, 9530, 9520, 9630 from Farnell and Rapid.
£1.85 for the 9140 and 66p to 88p for the 95xx/96xx +VAT post free.
£1.85 for the 9140 and 66p to 88p for the 95xx/96xx +VAT post free.
Thanks teabag.... in addition to the 140-9140, I had also looked for 540/9540 and 9160. Most were available reasonably cheaply, but only schuro had both P and N channels ones. So you would have paid 2 sets of shipping etc etc.
We should really start putting together a list of the fets that can be subbed in and with what changes.......
Fran
Andrew simul post - farnell has teh 240 at 4.54 each though.....
We should really start putting together a list of the fets that can be subbed in and with what changes.......
Fran
Andrew simul post - farnell has teh 240 at 4.54 each though.....
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