EF3-3 or EF3-4? Please suggest for Polk Legend L600
Dear Wolverine team,
I do have a pair of Wolverine EF3-3 boards sourced from @fireanimal. I would like to pair the Wolverine with my Polk speakers which are rated at 4 Ohms(3.3 Ohms minimum) and 86db sensitivity. The Polk dealer suggested to pair the speakers with a high current 2 Ohms capable amplifier. Would I be able to use the EF3-3 here without any issues? OR should I wait for EF3-4 boards(I understand that EF3-4 boards are not in stock)? Please advise.
Transformer: 45-0-45 500VA per channel
Output transistors: OnSemi 2sc5200/2sa1943 or OnSemi MJL3281/MJL1302
Thanks
Sha
Dear Wolverine team,
I do have a pair of Wolverine EF3-3 boards sourced from @fireanimal. I would like to pair the Wolverine with my Polk speakers which are rated at 4 Ohms(3.3 Ohms minimum) and 86db sensitivity. The Polk dealer suggested to pair the speakers with a high current 2 Ohms capable amplifier. Would I be able to use the EF3-3 here without any issues? OR should I wait for EF3-4 boards(I understand that EF3-4 boards are not in stock)? Please advise.
Transformer: 45-0-45 500VA per channel
Output transistors: OnSemi 2sc5200/2sa1943 or OnSemi MJL3281/MJL1302
Thanks
Sha
Hello Fireanimal,
It is Polk Audio Legend L600 floorstanders
https://www.polkaudio.com/en-us/product/home-speakers/floor-standing/legend-l600/125057.html
Thanks
Sha
It is Polk Audio Legend L600 floorstanders
https://www.polkaudio.com/en-us/product/home-speakers/floor-standing/legend-l600/125057.html
Thanks
Sha
I cant find the graph, but the EF3-3 with MJL4281 / MJL4302 outputs will work for you. I would not use the outputs you listed above
Look like a rather well-behaved speaker. Lots of good media coverage on the lower tiered reserve series. There's a 300hz peak that needs taming in that measurement - but that's not an anechoic measurement so can't rule out room effects being the cause. Interestingly, the low impedance is mostly all in the tweeter. The overall power dissipation in that reigon in music should be lower, but I'll leave it to more experinced members to comment on how the wolverine might behave with that.
I run a comparable setup.
EF3-3 bord with OnSemi 2SC5200/2SA1943 outputs
1000 VA toroidal with 4 x 36.000 uF for both channels total
Four SEAS Exel W17E-002 titanium mid/bass, two each channel, connected without passive filters for 4 ohm nominal each side.
Superb quality, without any problems.
Dont use the 2SC500/2SA1943 with those speakers please, they will be outside their SOA, stick with the MJL series on the EF3-3
@fireanimal - Thanks a lot for the green signal. I shall use MJL4281/MJL4302.
Thanks to others as well for the comments/inputs 🙂
Regards
Sha
Thanks to others as well for the comments/inputs 🙂
Regards
Sha
Hi, I'm new here and if I can get PCBs I'm looking to build a Wolverine early next year.
Interesting I came across your post with this kind of alternative power supply, only issue would be huge import taxes to UK/Ireland with this supply or indeed other parts I would need to import. Alternatively the regular power supply could be cheaper, I have 2x spare toroids, maybe 250VAC 35-0-35 but I'll have to check and maybe these are just short of being good enough for Wolverine. I can also get used good brand 500VAC 40-0-40 toroidal on Ebay for £50-£60 or I don't mind buying new either from RS, Farnell or Mouser suppliers here. I can even buy the same toroidal transformers that Naim use which are made in Ireland.
I've installed an ANTEK 800va 40-0-40 toroid along with an ANTEK softstart, used all the correct wiring and layout you guys recommended. DC offset to 0.00, R11 to achieve 5.0 V, BIAS to 44ish mV. Everything stays cool, good so far. Connect speakers and turned on, perfect, zero noise.
Now when I hook up a preamp, does not matter which one, Yamaha C-50 or one I built from Elliott Sound Products, I get a very quiet 60hz hum.
I've done all the testing for ground loops and everything is correct. I even took the cover off and hooked up a totally separate set of input RCA's directly to the amp boards and laid them out side of the chassis, completely away from power wires, nothing changed.
I noticed on the schematic that the input ground has Rlift and Clift between the input shield and 0 volt line. I haven't tried to bypass this ground lift yet but This is the only thing I can think of to do.
Looking at the outputs of my preamps and other amplified inputs, none have a ground lift, so If I'm hooking up the Wolverine to a preamp that has its output shield tied directly to the 0 volt, could this be causing the slight hum, ground loop?
When I get a chance, I will post what happens.
Scott
BTW, VERY NICE SOUNDING AMPLIFIER! Very powerful and clean. Nice on the ears. Glad you guys designed it.
Now when I hook up a preamp, does not matter which one, Yamaha C-50 or one I built from Elliott Sound Products, I get a very quiet 60hz hum.
I've done all the testing for ground loops and everything is correct. I even took the cover off and hooked up a totally separate set of input RCA's directly to the amp boards and laid them out side of the chassis, completely away from power wires, nothing changed.
I noticed on the schematic that the input ground has Rlift and Clift between the input shield and 0 volt line. I haven't tried to bypass this ground lift yet but This is the only thing I can think of to do.
Looking at the outputs of my preamps and other amplified inputs, none have a ground lift, so If I'm hooking up the Wolverine to a preamp that has its output shield tied directly to the 0 volt, could this be causing the slight hum, ground loop?
When I get a chance, I will post what happens.
Scott
BTW, VERY NICE SOUNDING AMPLIFIER! Very powerful and clean. Nice on the ears. Glad you guys designed it.
Attachments
Did you recheck Bias after 30 minutes and maybe even an hour? Depending on size of heatsink, this amp does not run cold, more around 40-45 celsius at idle.
I used the 2.2 ohm resistors for Rlift. Would using the 4.7 ohm change anything or would it make it worse?
You could try 4.7R but from our testing there was no change.
Did you follow the suggestion in the wiring guide for the cap to chassis?
Other than that, its a bit of a tricky one the wolverine will amplifier whatever it sees on the input by approximately 27 times so if your pre amp has 1mV of noise on its output then its going to be amplified by 27 times on the Wolverine's output.
Do you have a scope or a good quality DMM that you can measure the idle AC output of your pre amplifiers.
Maybe take a look at those.
