One more thing Andrew : did they change their policy for offering samples? My recent orders allows only 5 pcs at a time so even if I have the MJL4302AG, (and the MJL4281AG) I would had just enough for 1 channel.
Hi,
yes, Onsemi changed the samples policy.
But they confirmed with me that private requests should go through the samples route and continue to pay the delivery charge.
The big drawback of the 5 limit is that batches for matching are impossible.
yes, Onsemi changed the samples policy.
But they confirmed with me that private requests should go through the samples route and continue to pay the delivery charge.
The big drawback of the 5 limit is that batches for matching are impossible.
i have 50pairs of these and i intended to use them on the Leach super amps had the project pushed thru....😀
sure you may use them...
i have the original leach super amps boards but i gave them away in anticipation of jens new pcb layout...
i guess i will be forced to learn protel or get someone wwho can do it for me...😀
i guess i will be forced to learn protel or get someone wwho can do it for me...😀
Hi,
the super Leach could run on one set of output transistors.
Just like any other push pull output stage.
The difference is that the cascoded pairs allows higher voltage ability.
Obviously, one set limits ability to higher impedance loads and again just like the conventional output stage, more parallel pairs allows lower impedance loads to be driven.
the super Leach could run on one set of output transistors.
Just like any other push pull output stage.
The difference is that the cascoded pairs allows higher voltage ability.
Obviously, one set limits ability to higher impedance loads and again just like the conventional output stage, more parallel pairs allows lower impedance loads to be driven.
hey bigpanda,
pm answered, i suggest you post your board layout here, i am sure there are those interested on the boards. i am looking for another approach to building this amps..
pm answered, i suggest you post your board layout here, i am sure there are those interested on the boards. i am looking for another approach to building this amps..
i want to keep this thread alive, so i asked a friend do me an ouput stage of the super leach using 32 output transistors...i am interested to know about your thoughts on this...😀
here it is:
here it is:
okey, the output zobel network is moving out of the board and will be mounted direct accross the speaker terminals on its' own board.
the output stage will have its own board just like jens' layout. the input and drivers then will mount on a separate board atop this output stage board and connected via molex connectors with short leads...
the output stage will have its own board just like jens' layout. the input and drivers then will mount on a separate board atop this output stage board and connected via molex connectors with short leads...
Hi,
what operating conditions are you designing to meet? It seems that an 8 quad set is way over most folks requirements.
Why have you persisted with the series cap on the Zobel at the output?
Why have you added emitter resistors to the cascodes?
Why have you coupled all the cascodes together?
This is no longer a Leach Double barrelled, the topology has been changed.
What drivers are you planning?
What quiescent current are you planning?
what operating conditions are you designing to meet? It seems that an 8 quad set is way over most folks requirements.
Why have you persisted with the series cap on the Zobel at the output?
Why have you added emitter resistors to the cascodes?
Why have you coupled all the cascodes together?
This is no longer a Leach Double barrelled, the topology has been changed.
What drivers are you planning?
What quiescent current are you planning?
the amp will have +/-85 rails unloaded, power coming from a 2.5kVA EI power transformer. i hope to be able to run the amp at 1kw at 2 ohms, if that is possible.
that was a mistake, single cap is enough.
they are part of the original design and i see no reason to do away with it.
again this is part of the original design....
way i see it, only the number of output devices have changed.
i intend to use these transistor compliments:
output => MJL2193/MJL2194
drivers => MJW1302A/MJW3281
pre-drivers and VAS = > 2SC4793/2SA1837
small signal transistors, i haven't decided yet, i am looking at several japanese to-92's, but i am open to using the original parts.
that will de decided when the amp is built and tested.
i have lots of power transistors on hand....
😀
Hi Tony,
Sorry.
The double barrelled does indeed have coupled collectors below the cascodes. I had not picked that up in the simple two pair schematic.
The numbers stack up well for 2ohm.
8 quads can achieve 1kW @ 60degree phase angle and with Tc<100degC. Sink ~<90degC
This was some test for Bensen's SOA spreadsheet. I have never tried to do a cascaded output stage before.
I estimate that power from +-76Vdc with +-60mF per channel after you have biased it up. Iq=400mA from +-76Vdc Pq=61W. That will need a fairly big sink, but your going to have that just to fit 32 To3s in place.
Sorry.
The double barrelled does indeed have coupled collectors below the cascodes. I had not picked that up in the simple two pair schematic.
The numbers stack up well for 2ohm.
8 quads can achieve 1kW @ 60degree phase angle and with Tc<100degC. Sink ~<90degC
This was some test for Bensen's SOA spreadsheet. I have never tried to do a cascaded output stage before.
I estimate that power from +-76Vdc with +-60mF per channel after you have biased it up. Iq=400mA from +-76Vdc Pq=61W. That will need a fairly big sink, but your going to have that just to fit 32 To3s in place.
Hi all,
A quick update:
http://www.delta-audio.com/temp_jens/Super_Leach_ver_2.4_PCB.pdf
I changed the feedback, and consider getting rid of the large caps placed on the top of the board.
\Jens
A quick update:
http://www.delta-audio.com/temp_jens/Super_Leach_ver_2.4_PCB.pdf
I changed the feedback, and consider getting rid of the large caps placed on the top of the board.
\Jens
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