Hi,
I have amplifier Dual CV-441 RC
(on this link is some info about amp. : http://www.n-malek.de/11201/38347.html ) with burned left channel.
I think this amp. is not real class A, what you think?
Everything else is cheked and working exept BDV66D and BDV67D transistors, I try with tranny`s from right channel.
They is hard to find and they is too expensive.
Can I make DIY Darlingtons from 2STC5949 and 2STA2121 and can somebody tell how and what I need to change on amplifier, please?
There is link to service manual : Dual CV 440 Service Anleitung
Thank you in advance.
Regards
http://www.n-malek.de/11201/38347.html
I have amplifier Dual CV-441 RC
(on this link is some info about amp. : http://www.n-malek.de/11201/38347.html ) with burned left channel.
I think this amp. is not real class A, what you think?
Everything else is cheked and working exept BDV66D and BDV67D transistors, I try with tranny`s from right channel.
They is hard to find and they is too expensive.
Can I make DIY Darlingtons from 2STC5949 and 2STA2121 and can somebody tell how and what I need to change on amplifier, please?
There is link to service manual : Dual CV 440 Service Anleitung
Thank you in advance.
Regards
http://www.n-malek.de/11201/38347.html
To make darlingtons from 2STC5949 and 2STA2121 you should add drivers
like the mje15030/150301 pair with a 100R each , it is a valuable and quite
good solution given such a set would have better power handling capability
than the original scheme.
Otherwise you can use high performance darlingtons from Sanken
as the MP1620/MN2488 pairs if you can find
them at correct prices in a serious seller store..
like the mje15030/150301 pair with a 100R each , it is a valuable and quite
good solution given such a set would have better power handling capability
than the original scheme.
Otherwise you can use high performance darlingtons from Sanken
as the MP1620/MN2488 pairs if you can find
them at correct prices in a serious seller store..
tip 142 147 is the same ( and shame ) very easy and dirt cheap
but it will not stop there ... you need to have a lot more knowledge around darlingtons and sub products to be able to carry out a proper repair .
Most serious issues:
--BDV66-67 but D versions are pretty much unobtainable
--If found are probably fake
--You need to have proper information about the originals that you have inside your amp and their internal specific configuration IE resistors between driver and output may vary depending on the application,order,batch,brand, model ,version , year and some other 100 reasons i dont remember
It is practically impossible to know what was inside your BDV66 you had next to the ones that you are going to get from the open market ...
---One way or another BDV 66 even D is overestimated to operate at 57+57 volts and its expected to produce >120W which is a dream and can only be achieved from perfect semis
--One way or another the SOA of the specific circuit is extremely poor and its based on how robust is the output transistors ( especially when the circuit is made without a VI limiter )
REAL LIFE SOLUTIONS
--find the best quality TIP 142C-147C you can get of course this has to be same brand batch make family and so on ..to my opinion replace emitter resistors from 0.33 to even 0.68 re tune the amp to the specific idle expect the amp to become slower and some power less at the end but it will work a bit more safe ....
---Modify the all circuit ( far too easy ) to operate with normal transistors like 1943 5200 and beyond safety you will get the chance to listen to some real music ...
but it will not stop there ... you need to have a lot more knowledge around darlingtons and sub products to be able to carry out a proper repair .
Most serious issues:
--BDV66-67 but D versions are pretty much unobtainable
--If found are probably fake
--You need to have proper information about the originals that you have inside your amp and their internal specific configuration IE resistors between driver and output may vary depending on the application,order,batch,brand, model ,version , year and some other 100 reasons i dont remember
It is practically impossible to know what was inside your BDV66 you had next to the ones that you are going to get from the open market ...
---One way or another BDV 66 even D is overestimated to operate at 57+57 volts and its expected to produce >120W which is a dream and can only be achieved from perfect semis
--One way or another the SOA of the specific circuit is extremely poor and its based on how robust is the output transistors ( especially when the circuit is made without a VI limiter )
REAL LIFE SOLUTIONS
--find the best quality TIP 142C-147C you can get of course this has to be same brand batch make family and so on ..to my opinion replace emitter resistors from 0.33 to even 0.68 re tune the amp to the specific idle expect the amp to become slower and some power less at the end but it will work a bit more safe ....
---Modify the all circuit ( far too easy ) to operate with normal transistors like 1943 5200 and beyond safety you will get the chance to listen to some real music ...
There is two pairs of device per channel.
The rail voltage is +- 57V , unfortunately the usual cheap darlingtons are all out of range.
Besides , if he lives in continental europe this is the voltage for the old 220V main standard wich
was changed to 230V so in this case expect the rail to be at +-60V.
If he has an english market model wich is specified for 240V the PS voltage will be a little less,
but even then i wouldnt venture on using 100V devices with the hope that they are underspecced.
Unless the models i quoted or nearby ones are used , an adaptation of the devices
he has at hand is the best option.
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Thanks on answers.
I think that this 2ST trannys can easy make work in my Dual but
its like to me a big complication and it will best to give up and buy other amplifier.
Regards
I think that this 2ST trannys can easy make work in my Dual but
its like to me a big complication and it will best to give up and buy other amplifier.
Regards
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