I roughly calculated 20 ohm when you talked 58V initially and I thought of 10 ohm when you found 55V. But put 20 Ohm which is safely more drastic and measure the loaded result. Its not easy to calculate spot on for various unknown in detail transformers. If it results over 42VDC is acceptable and if between 45VDC-48VDC most nice.
Most my bom is now oh-hand for the lomc version. I mainly use a denon 301-ii but have a 103r too. Have my eye on the at33sa or ortoton quintet black in the next six months.
I'd appreciate recommendations for c3 & c4. I've seen murdorf supreme mentioned. (0.1uf for c3, and 2.2uf for c4.) Those prices seem rational.
Thanks.
I'd appreciate recommendations for c3 & c4. I've seen murdorf supreme mentioned. (0.1uf for c3, and 2.2uf for c4.) Those prices seem rational.
Thanks.
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Listening to my latest version with Jupiter copper on output. Sounds wonderful and can't argue that it wouldn't be possible without Salad
When its not static electricity its Buz force intimidating that poor leggy MOS
I like ClarityCap MR a notch better. But pricier. Supreme is VFM in this context. You are eying a couple of excellent cart choices I must agree.
EU equipment or equipment retailed in the EU must comply with the EU harmonised mains supply voltage.
That means it is marked with the harmonised nominal voltage of 230Vac.
It must be capable of operating properly over the whole range of the EU harmonised voltage, i.e. from 216Vac to 253Vac.
Any transformer that does not operate properly on 253Vac does not comply.
Send it back and demand a full refund.
I suspect that a lot of the transformers manufactured in the Far East do not comply, simply because the Manufacturer does not understand what they are making, nor what their obligations are when they supply to an EU importer !
And some of the EU retailer/importer don't care who they kill with their cheap equipment. We regularly see ultra cheap SMPS that do not comply and injure EU users.
This importing of non compliant electrical equipment is criminal !!!!!!
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Having strong secondaries like from a little lower primary to secondary ratio in our kind of current draw for things like the FSP does not mean that they will not go to their nominal secondary values when fully loaded to their power capacity. They come from a large Indian factory with all sorts of official quality controls and big name client companies. Lucylu's are designed and made in the UK but they still give 20.5+20.5=41 VAC when providing 120mA current for instance. When they are labeled as 18+18. I would think its all about being rated at full load capability again.
VA rating and regulation are quite different and different again from EU voltage compliance.
A transformer has regulation.
The ratio between open circuit output voltage and the loaded circuit output voltage.
High VA tend to have lower regulation.
EI tend to have higher regulation.
Capacitor input filter adds to the complication of modeling and predicting working voltages at the PSU.
The easy way is to build and measure.
But for compliance and non compliance with EU harmonisation, it is much more difficult, Heat in the transformer may be a guide that something is not right. Not secondary output voltages.
A transformer has regulation.
The ratio between open circuit output voltage and the loaded circuit output voltage.
High VA tend to have lower regulation.
EI tend to have higher regulation.
Capacitor input filter adds to the complication of modeling and predicting working voltages at the PSU.
The easy way is to build and measure.
But for compliance and non compliance with EU harmonisation, it is much more difficult, Heat in the transformer may be a guide that something is not right. Not secondary output voltages.
15+15Vac are very common.
It would be very easy to add a 2Vac winding around the outside of the toroid core.
It could be as little as 4 to 6Turns of enameled copper wire.
and while you are in winding mood add a second group of turns.
Lets one adjust the final voltage if the first was not quite right.
It would be very easy to add a 2Vac winding around the outside of the toroid core.
It could be as little as 4 to 6Turns of enameled copper wire.
and while you are in winding mood add a second group of turns.
Lets one adjust the final voltage if the first was not quite right.
Resistors came today (20ohm) so fitted and my volts are with load resistors fitted ac 43,,,dc 49.6 without load 57/58 vdc
I wanted to get it down a little more to Salas 45/48 most nice area so I added 4r7 wirewound to 20ohm which gave me ac 42,,,dc 47/48 with no load 56.3 dc.
I hope that's it
I wanted to get it down a little more to Salas 45/48 most nice area so I added 4r7 wirewound to 20ohm which gave me ac 42,,,dc 47/48 with no load 56.3 dc.
I hope that's it
Attachments
Biasing
Yes spot on Salas, so need step I put it together and switched on no problems all leds on looking good but ! rail and gnd only measure 30v/32v and vr2x is at max
So reading guide and an old post I switched resistors r3x from 9.1k to 6.2k and r6x from 22r t0 33r doing this should raise volts Wrong opposite happens 22v/23v .
Looking at that I should increase .Please advice
Yes spot on Salas, so need step I put it together and switched on no problems all leds on looking good
but ! rail and gnd only measure 30v/32v and vr2x is at maxSo reading guide and an old post I switched resistors r3x from 9.1k to 6.2k and r6x from 22r t0 33r doing this should raise volts Wrong opposite happens 22v/23v .
Looking at that I should increase .Please advice
When you can't reach 35V+ with R3x 9.1k it means that Q3x is from a low IDSS range and you should compensate with higher value R3x than what is now installed. That resistor with VR2x (in series) convert the current provided by Q3x to voltage. Q4x and D1x contribute 0.6V+1.8V and the rest comes from the resistances. So either add 2.7k in series with 9.1k R3x or install 12K in its place. That should do it. Because it looks like you got about 3mA @ 10V IDSS Q3xs that do about 2.5mA current under 0.6V they work in the circuit. On the other hand its good because low IDSS ones have lower Vgs (off) and work better under low VDS voltage (Q4x's Vbe that is)
Hi Salas,
I am testing the boards on a LAB supply now.
Power into the amp boards is 44.2VDC. My LAB supply will not go any higher.
I see something strange. One of the boards will not go over 26.5VDC Rail. And the TP1/TP2 reading is 5.5VDC.
The other board has no such problem and can be tweaked as dicribed in the file. 3.6VDC on TP1/TP2.
What could be the problem?
kind regards,
Sjoerd
I am testing the boards on a LAB supply now.
Power into the amp boards is 44.2VDC. My LAB supply will not go any higher.
I see something strange. One of the boards will not go over 26.5VDC Rail. And the TP1/TP2 reading is 5.5VDC.
The other board has no such problem and can be tweaked as dicribed in the file. 3.6VDC on TP1/TP2.
What could be the problem?
kind regards,
Sjoerd
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Its possibly having a low IDSS Q3x in the low rail channel. Just like Lucylu only not in both. At least this is a typical condition I suspect first. Add some value to its R3x to confirm. Something like 3.3k extra. If its so, either install a stronger Q3x or keep the R3x higher value that you will find enough. BTW what is your C3? Orange Drop PP?