Apex B500 or ... slewmaster MT-200 BJT
(below) is a good 250+ /8R and 500W @ 4R with 70V rails ( 500VA trafo/40kuf).
Plenty of SOA with 3 -pair Sanken MT-200. I only have a 400VA - 60Vdc rail power supply , so only 200W
for my 8R woofer.
BJT can do it (you don't always need D) .
OS
(below) is a good 250+ /8R and 500W @ 4R with 70V rails ( 500VA trafo/40kuf).
Plenty of SOA with 3 -pair Sanken MT-200. I only have a 400VA - 60Vdc rail power supply , so only 200W
for my 8R woofer.
BJT can do it (you don't always need D) .
OS
Attachments
Thanks , MT-200's were sort of made for "grunt" - 6+ A SOA @ 60V.
Besides Semelab's "special BJT's" , they are the only choice for
any 2-4R loads (Sub's). Very low beta .... only good with EF3's. Single pair mt-200
classic Japanese amps are often rated 100-125W units. Multiple pair needs TO-3P
drivers.
Edit - 3 pair (18A) blow away even 5 pair ON TO-3p/264 - @ 10+ A (100ms).
OS
Besides Semelab's "special BJT's" , they are the only choice for
any 2-4R loads (Sub's). Very low beta .... only good with EF3's. Single pair mt-200
classic Japanese amps are often rated 100-125W units. Multiple pair needs TO-3P
drivers.
Edit - 3 pair (18A) blow away even 5 pair ON TO-3p/264 - @ 10+ A (100ms).
OS
Last edited:
@ostripper
Its a beauty.
Could you share its pcb and schematics.
Just updated the first post - 10 input stages that you can hook to 3 output
stages (modular).
Link - http://www.diyaudio.com/forums/solid-state/248105-slewmaster-cfa-vs-vfa-rumble.html#post3753356
Post # contains schema / toner artwork ...
OS
Hi OS! Why do you say only choice?Thanks , MT-200's were sort of made for "grunt" - 6+ A SOA @ 60V.
Besides Semelab's "special BJT's" , they are the only choice for
any 2-4R loads (Sub's).
OS
I am going from a lot of time with 5 pairs TO3 (metal cans) Motorola/ONsemi 15003/15004. 10 Pairs for 2 Ohm.
Never had a trouble, PA use as well. While I like the MT200 as well, I do not think they are only choice.
Hi OS! Why do you say only choice?
I am going from a lot of time with 5 pairs TO3 (metal cans) Motorola/ONsemi 15003/15004. 10 Pairs for 2 Ohm.
Never had a trouble, PA use as well. While I like the MT200 as well, I do not think they are only choice.
"Only CHEAP choice" ... MJ15xxx are SLOW as dogpoo (2mhz)
I guess for a subamp - OK ? harder to source than plastic packages.
Mt- 200's are 35mhz fT.
OS
@Apex
I finally Desired to go with Apex B500 Amplifier,as it seems a good variant for DIY .
Go ahead and build it .... but 4 pair with a EF2 is hardly 500w . The forum amp ,
(badger) is exactly the same minus 1 pair - rated at 150 -8R /250 - 4R .
OS
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