I'm saying Donuts - simple but important reason - magnetic field of those is smaller than, say, of small EI (which we all probably have around)
I'm ordering mine custom made, 20VA with dual 30Vct, 10VA 24Vct , both static and magnetic shield
just saying - I know I'm lucky having local Vendor for that
I'm ordering mine custom made, 20VA with dual 30Vct, 10VA 24Vct , both static and magnetic shield
just saying - I know I'm lucky having local Vendor for that
Yeah, I usually have some custom transformer made by Toroidy in Poland. I usually order the encapsulated version but the non-encapsulated is also totally silent. Toroidy has Amazing quality and price is also not bad. In North Amarica we do have several transformer manufacturers but prices are very high when asking for custom.
I'll buy some R-Core because the regulation is supposed to be better, especially compared to small toroids, also magnetic field is supposed to be even less. Who knows, I might go back to Toroidy, my go to for transformers.
Do
I'll buy some R-Core because the regulation is supposed to be better, especially compared to small toroids, also magnetic field is supposed to be even less. Who knows, I might go back to Toroidy, my go to for transformers.
Do
Man! This thing is so easy to adjust! Rail voltages are all spot on +/-12V give or take 0.02V, Bias voltage is same thing and very stable. DC offset is also the same, very stable! Me like this very much!
Now time to check with a sine wave and make sure everything is ok out of the buffer before plugin in the TVC.
Also, I need to clean the underside of my board from all the solder flux. I have not yet tested the selector and volume control with 24v... I need to find a 0-24V or dual 0-12v and center tap it (not connecting the center tap, just to get 24v.
Things are shaping off pretty good so far!
Thanks ZM!
Do
Now time to check with a sine wave and make sure everything is ok out of the buffer before plugin in the TVC.
Also, I need to clean the underside of my board from all the solder flux. I have not yet tested the selector and volume control with 24v... I need to find a 0-24V or dual 0-12v and center tap it (not connecting the center tap, just to get 24v.
Things are shaping off pretty good so far!
Thanks ZM!
Do
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I've learned to clean the flux the hard way,
one of my first DIY projects was a KT88 amp,
the first time I switched it on there was a bang and smoke,
it seems that the remaining flux was conductive between 450vdc B+ and ground.
It was easy to spot on the PCB at the extra hole where the traces were
one of my first DIY projects was a KT88 amp,
the first time I switched it on there was a bang and smoke,
it seems that the remaining flux was conductive between 450vdc B+ and ground.
It was easy to spot on the PCB at the extra hole where the traces were
Here's the backplate of my SE iron pumpkin.
I've only used 4 of 5 inputs, 4 is still plenty for me.
The XLRs are not balanced but SE inputs and connected to the same RCA input,
so I can use SE XLR or RCA for the same input.
I use the very good Neutrik XLR NC3FD-LX-BAG NC3MD-LX-BAG connectors.
I've only used 4 of 5 inputs, 4 is still plenty for me.
The XLRs are not balanced but SE inputs and connected to the same RCA input,
so I can use SE XLR or RCA for the same input.
I use the very good Neutrik XLR NC3FD-LX-BAG NC3MD-LX-BAG connectors.
Attachments
Hi Zen Mod,
I've tested everything as far as parameters goes and it all works fine hooked up on the scope. Now testing the sound when in chassis and I'm getting hum starting on position 8 and increasing up until 13, then quiet on 14. Then it starts again on 15, increases (+/- in some positions) until 19, then back to quiet on 20 and same thing from 21-23 and silent on 24...
This is happening on both channels. Tried different amplifiers and sources.
What I've been trying is unbalanced inputs and outputs for now. Jumper is on for inputs 1-2 (unbalanced) and for output I'm using balanced GND and positive phase. Is that ok?
Also changed gain from 2 to 0 and it made no difference. The front of my chassis is not completed yet (only part), so volume knob and selector knob are not chassis grounded, if that can make a difference?
Thanks
Do
I've tested everything as far as parameters goes and it all works fine hooked up on the scope. Now testing the sound when in chassis and I'm getting hum starting on position 8 and increasing up until 13, then quiet on 14. Then it starts again on 15, increases (+/- in some positions) until 19, then back to quiet on 20 and same thing from 21-23 and silent on 24...
This is happening on both channels. Tried different amplifiers and sources.
What I've been trying is unbalanced inputs and outputs for now. Jumper is on for inputs 1-2 (unbalanced) and for output I'm using balanced GND and positive phase. Is that ok?
Also changed gain from 2 to 0 and it made no difference. The front of my chassis is not completed yet (only part), so volume knob and selector knob are not chassis grounded, if that can make a difference?
Thanks
Do
just a general reminder - you did put jumpers (for energizing 6th relay) for each SE input?
also, on SE inputs, input pad 3 must be shorted to pad 1 (tiny wire bridge)
regarding SE out, that's correct - using GND and positive hot
no need for grounding of rotary switches, relay PSU is anyway in all possible ways isolated from audio PSU
if you did everything by the book (I can't recollect did you posted/sent pictures of your build) , only way of deducing what is culprit is to move transformers out of box, expecting that all hum is gone
I can bet that will be problem solver; R Core or not, I'm trusting in particular xformer only when there is no hum, with them in box
In my builds I'm using 20VA (on 30VA core, due to plenty of secs, space issue) for audio and 10VA for relays/logic ; both xformers Donuts, with static shield and magnetic shield ; no hum at all, with Donuts situated in front right corner of preamp, ditto behind front plate
post pictures, so I can comment
try moving xformers out temporary, and inform us of result
forgot to reply specifically - no, phasing of secondaries is not important at all