And I have questions about operating voltage of Cresendo ME.
In schematic recommend 45-50 VDC (about 35 VAC) so can I use lower or higher voltages?
I can get transformers with 30 VAC (about 42VDC) or 38 VAC (about 53 VDC).
Which one is better? And do I have make some modifications in schema if I use lower or higher voltages?
Thanks!
In schematic recommend 45-50 VDC (about 35 VAC) so can I use lower or higher voltages?
I can get transformers with 30 VAC (about 42VDC) or 38 VAC (about 53 VDC).
Which one is better? And do I have make some modifications in schema if I use lower or higher voltages?
Thanks!
The 2*38 VAC secondary will give you about 2-4 volts lower than 53 VDC after losses in the rectifier and elsewhere so I would go with the higher voltage. I haven't read the new Elektor Crescendo article (I still have the originals from the 80's though...) and I don't know what the class or bias is but remember that the 38 VAC is UNDER LOAD and that if bias is low the voltage may be a few to maybe even 10 % higher. General rule according to me is to use the highest capacity transformer you can find/afford since the power supply will be tougher and the difference between no load and load voltages decrease with higher capacity (all that internal resistance of secondary windings I think).
/UrSv
/UrSv
I have other question now about Crescendo ME.
Can I replace OP77GP with OP07CP, OP27GP or OP37GP. This OP77GP are used in a sort of Offset compensation.
Because I can´t get this OP77GP.
OP77GP Input Offset Voltage -values typical 50yV(micro V) and Max 100yV.
OP07CP Input Offset Voltage -values typical 60yV and Max 150yV.
OP27GP and OP37GP Input Offset Voltage -values typical 30yV and Max 100yV.
Sorry my very bad English...
Can I replace OP77GP with OP07CP, OP27GP or OP37GP. This OP77GP are used in a sort of Offset compensation.
Because I can´t get this OP77GP.
OP77GP Input Offset Voltage -values typical 50yV(micro V) and Max 100yV.
OP07CP Input Offset Voltage -values typical 60yV and Max 150yV.
OP27GP and OP37GP Input Offset Voltage -values typical 30yV and Max 100yV.
Sorry my very bad English...
Here is mine
Here is my elector amp, oh and the 4 channel pre-amp i made:
it has 4*22,000uF rifa's
500W transformer
Here is my elector amp, oh and the 4 channel pre-amp i made:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
it has 4*22,000uF rifa's
500W transformer
eccu,
sure
the LF411 was used very often by Elektor for dc-servo´s. A few power amps used them and I still use it in the phono section of my preamp. I changed it for a OP77 in my power amp when I rebuild this.
I think it´s not so important if the power amp has 0,1 or 2mv (or even 20mV) offset as long as it´s below say 50-100mV. The difference in input offset voltage between the op77 and the LF411 will only cause the amp to have 1 or 2 mV more offset.
william
sure
the LF411 was used very often by Elektor for dc-servo´s. A few power amps used them and I still use it in the phono section of my preamp. I changed it for a OP77 in my power amp when I rebuild this. I think it´s not so important if the power amp has 0,1 or 2mv (or even 20mV) offset as long as it´s below say 50-100mV. The difference in input offset voltage between the op77 and the LF411 will only cause the amp to have 1 or 2 mV more offset.
william
thanks wuffwaff... )
but can I still use OP07 or OP27... ?
OP77 datasheet shows that it is Next generation OP07... so I think that OP07 is better combatible with OP77GP than LF411...
So which one is best choice, because I can get these:
OP07CP costs about 1,6 € (Euros),
OP27GP costs about 3,8 € (Euros) and
LF411CN costs about 1,9 € (Euros).
)but can I still use OP07 or OP27... ?
OP77 datasheet shows that it is Next generation OP07... so I think that OP07 is better combatible with OP77GP than LF411...
So which one is best choice, because I can get these:
OP07CP costs about 1,6 € (Euros),
OP27GP costs about 3,8 € (Euros) and
LF411CN costs about 1,9 € (Euros).
OP 77, OP177 and OP277 (and OP-97) are all upgrades of the standard OP-07, so they can all replace OP-07 in a DC-servo, basically any pin compatible modern op with low-offset , low bias can replace OP-07 in this circuit. (the higher number ,the better op)
OP-27 have much higher bandwidth and slew rate than the OP-07, but used in a DC-servo, this shouldnt matter since the servo loop is bandwidthlimited to about 1 Hertz or so. It could probably be used in a DC-servo circuit.
OP-37 is NOT unity gain stable (min gain 5 ) so I dont think it can be used in a DC-servo circuit.
/rickard
OP-27 have much higher bandwidth and slew rate than the OP-07, but used in a DC-servo, this shouldnt matter since the servo loop is bandwidthlimited to about 1 Hertz or so. It could probably be used in a DC-servo circuit.
OP-37 is NOT unity gain stable (min gain 5 ) so I dont think it can be used in a DC-servo circuit.
/rickard
the output transistors for the millenium cresendo are sold by ELFA:
check out page 796-797 in the new catalouge under "ersättningshalvledare" but they are quite expensive.
www.elfa.se
/rickard
check out page 796-797 in the new catalouge under "ersättningshalvledare" but they are quite expensive.
www.elfa.se
/rickard
swede said:
In Finland / Oulu (Uleåborg)... there is an electronics shop named spelektroniikka (www.spelektroniikka.fi only in finnish)...
But I think that in Elfa has too these Fet´s.
2SJ201
2SK537 (equiv. 2SK2733)
2SK1530
I hope you understand my Enlgish
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