Ha ha, that youtuber don't recommend it due to blockages. Not a good choice of video to link to.
Is interesting the tip is made from silicone. I'm been using a RS branded solder sucker for almost 20 years and still performing well. However, I go through quite alot of Teflon tips due to burns so may try sliding on a silicone tube to see if it's more effective and last longer.
I don't see where I advised you to get a new iron and I did not mention a vacuum desoldering gun.
55C is surely not a reliability problem. C2 charges up to reach max has to be an explanation, there is no turn on spike just a smooth curve that you can capture in single trigger if you set a scope very slow, how many uF C2 you use and what is the Vout?
I think it was few hundreds of mSec for 220uF at 10V when I measured it. If you simply watch the scope moving up its DC line during start up you should get a pretty good visual clue. Its soft start, but if some application has issues with that you may cut its time in half by paralleling another 270R on top of each R5, R6, that would double the current supply to C2 and VR1 should be set half value lower of where it now is for same Vout. C2 100uF without other changes would produce the same decreased time too, but maybe you would object its ultralow frequencies more noise or not.
Those are good only for M1 when the CC is less than 1A and you don't have the Fairchilds but not for M2
Make sure there is enough CC setting for the load so enough spare current remains for the reg and its not nearly starved for current so that is why it reaches a target slower than others experience or it changes thermal settling behavior with and without the load. Paralleling some handy resistor value from the spares box on R1 to drop its value by 25% or something around that percentage should answer if this scenario holds any water.
No, the production files are GB material. I just have my few green prototypes, (+/-) two sections only in basic quality, and I can send you one if you are in a big hurry. PM me if so.
hi salas,
i want to power a soekris board with your 1.3 bib. you already stated:
do you think that a 30VA trafo has too little headroom, or would this type work e.g.:
Transformer R-CORE 30VA 12-0-12V + 1x9V - Audiophonics
it seems quite difficult to get the right r-core in europe, but i have to admit, i am very new to this DIY business
thanks in advance!
i want to power a soekris board with your 1.3 bib. you already stated:
do you think that a 30VA trafo has too little headroom, or would this type work e.g.:
Transformer R-CORE 30VA 12-0-12V + 1x9V - Audiophonics
it seems quite difficult to get the right r-core in europe, but i have to admit, i am very new to this DIY business
thanks in advance!
It shows 8VA per 12V side, it should be just enough for the DAC because the above total CC setting quote calls for 2.7W averaged per side at 12VAC. Tx capability to load ratio must be high enough to run cool especially when for constant current and full bridge. R-Core does not get easily hot like EI. For Soekris further specifics I don't know, there are versions, so for better info on what's best voltage setting for what version etc. ask the experts in the Soekris threads. I just had DimDim's build around and we run an experiment back then.
thanks salas,
i knew, why i was asking.
so this one should be the right one for the ultrabib&soekris-dac?
Transformer R-CORE 30VA 2x12V - Audiophonics
(there is also a 15V version, if it would suit the bib more...)
i knew, why i was asking.
so this one should be the right one for the ultrabib&soekris-dac?
Transformer R-CORE 30VA 2x12V - Audiophonics
(there is also a 15V version, if it would suit the bib more...)
This one is good. Because it has four wires and it does not spend VA to a third auxiliary secondary. If you have the sinking a 15VAC version will run M1 hotter but also in higher VDS voltage the less internal pF makes M1 bit faster and it will be handy for other uses too like powering a +/-15V op-amps output stage in a future DAC for example.
Thank you Salas. After paralleling 270R to R5 and R6 the startup is much quicker. I've also increased R1 to 2R2 (was 1R5) as my preamp was only drawing 190mA @ 18V and not 300mA. As a consequence M1/M2 operating temperature is now about 40C which is much cooler compared to before at 70C.
Having done some listening, it could be my imagination but I found the sound quality not quite as good as before such as the vocals seem not as warm sounding. Would the change in value for R5 and R6 make an audible difference?
The change in R5 R6 could be allowing for a slightly more noisy operation of the Vref transistors but I would consider it a trivial amount. I would suspect the change from 0.21A spare current to 0.082A to be audible. Do you have some resistor combination to create 0.15A spare? Like using 1.8 Ohm R1 resistor equivalent.
