Morning all. I would like to build this amp, however need to figure out the space requirements.
Is dissipante 4u/ 300 deep the smallest enclosure suitable for the amplifier ?
Thanks
Is dissipante 4u/ 300 deep the smallest enclosure suitable for the amplifier ?
Thanks
I am using a 4U/300 dissipante for my EF3/3 build. Depending on the choice of powersupply, it's a tight fit. EF3/4 wont fit.
I know it's a class ab amp. But we all know that very low distortion numbers say nothing about sound quality.
The problem is that I have the impression while listening to the extracts on youtube that it's a bit aggressive but hey, that's just my opinion.
You have to be kidding me right. You are comparing sound quality from a YouTube video! I can't even list all the reasons how that would not be a valid way to assess any amplifier or speaker for that matter..
This is the best amp I've ever had the pleasure of listening too, no matter what class.
Perhaps Stale25 should build the Wolverine so that she knows how good it is before sharing "opinions".
I know that the mjl21193/94 are not recommended for this amp anymore, but can you guys measure the hfe of some of them ?
The datasheet says that the hfe for these transistors should not be more than 75 and I have a bunch of 21193 with the hfe between 90 and 103, while the 21194 will measure between 33-41.
thanks
The datasheet says that the hfe for these transistors should not be more than 75 and I have a bunch of 21193 with the hfe between 90 and 103, while the 21194 will measure between 33-41.
thanks
Hi asuslover,
These small and cheap "transistor testers" measure at low currents and usually do not provide acurate results, especially for larger power transistors. You simply get a single point result, far away from the actual operation point.
Better solution is to use curve tracer - I am using "CH-012 Transistor Curve Tracer Adapter for OSC" from thaikits.com. To use it you need a digital oscilloscope in X-Y mode.
A snapshot shown below illustrates what you get. The point is that you may measure closer to the real operating point and it provodes a graph of Collector current vs. Collector-emitter voltage. These graphs in data sheets are just for information. The real world values may be different.
"Complementary tranistors" are often complementary in the name only.
.
Attachments
Last edited:
Hi everybody,
So it seems writing way to much information on a tiny piece of paper can lead to ordering the wrong output transistors.
After watching Daniel's very helpful videos(thanks Daniel) I was going with the NJW0281 + NJW0302 followed by MTL3281 + MTL1302 but also had the NJW3281 + NJW1302 in the mix which were accidentally ordered.
The basic difference s between transistors make sense but I don't understand what the variations in hFE and other parameters have on performance. Is a transistor with a certain hFE desired in this position? Did anyone have any advice or preference for the transistors mentioned or not mentioned?
I would really like to make this amp as good as possible so don't mind ordering new ones.
I'm going to build the EF3-4 @59v for speakers 4ohm 87db.
I also noticed that @fireanimal had matched pairs of A1381E +C3503E. Would love to buy some. If that's ok? I live in Australia. Sorry if it's inappropriate to ask this way. I can't pm.
Thanks for any help.
Jeremy
So it seems writing way to much information on a tiny piece of paper can lead to ordering the wrong output transistors.
After watching Daniel's very helpful videos(thanks Daniel) I was going with the NJW0281 + NJW0302 followed by MTL3281 + MTL1302 but also had the NJW3281 + NJW1302 in the mix which were accidentally ordered.
The basic difference s between transistors make sense but I don't understand what the variations in hFE and other parameters have on performance. Is a transistor with a certain hFE desired in this position? Did anyone have any advice or preference for the transistors mentioned or not mentioned?
I would really like to make this amp as good as possible so don't mind ordering new ones.
I'm going to build the EF3-4 @59v for speakers 4ohm 87db.
I also noticed that @fireanimal had matched pairs of A1381E +C3503E. Would love to buy some. If that's ok? I live in Australia. Sorry if it's inappropriate to ask this way. I can't pm.
Thanks for any help.
Jeremy
Hi Jeremy, the NJW3281/1302 transistors are excellent choices BUT have the TO3P case rather than the larger TO264 case of the MJL versions which potentially run cooler. (ON Semi do not give temp rise junction to ambient for both) I believe the silicon in each are is same. So your plan for EF3-4 @ 59Vdc and 4R loads is fine. Both MJL and NJW are hfe matched to 10% at Ic = 5A according to the data sheets.
I prefer the NJW3281 + NJW1302
They have lower cob and they are faster the the MJL transistors when you examine the ft plot.
Thank you for taking your time and answer, I am using Peak Atlas DCA75 Pro , and the hfe values for the 21193 are a little big .
Even though the Peak does not match at the ideal current for output transistors, I would still not use ones that measure as low as what you did.
Quite the contrary Jeremy, you helped all of us. Asking questions directly here in this thread is helpful to everyone, exchange by PM isn't.
Slight off topic. What is preferred line level attenuation for the Wolverine? I have an integrated at the moment and need to make decisions whether to make another integrated or make it into separate enclosure. In any case, looking for suggestions. Used to have b1 and ldr based atenuators. Thanks
The closed loop gain is about 27 Av or about 28.6 dB.
There is also 2 input impedance options ~22k and ~10k.
Hi Guy's, I'm very pleased to announce that the boards for the 2nd group buy have been ordered.
A big thank you goes out to all the members who ordered boards and made this group buy possible.
The interest in the Wolverine project keeps growing as we had even more interest this time around than we did in the first group buy. I look forward to seeing everyones builds coming together in the near future.
Jeremy and I have order a few extra for stock so we will have a few boards on hand for anyone who miss out on the 2nd group buy.
Stock is limited so if your interested please send us a pm and we'll try and help you out.
A reminder that @fireanimal has also offered his time to build completed amplifier modules EF3-3 and EF3-4. If your interested in this service please PM him for the details.
A big thank you goes out to all the members who ordered boards and made this group buy possible.
The interest in the Wolverine project keeps growing as we had even more interest this time around than we did in the first group buy. I look forward to seeing everyones builds coming together in the near future.
Jeremy and I have order a few extra for stock so we will have a few boards on hand for anyone who miss out on the 2nd group buy.
Stock is limited so if your interested please send us a pm and we'll try and help you out.
A reminder that @fireanimal has also offered his time to build completed amplifier modules EF3-3 and EF3-4. If your interested in this service please PM him for the details.
Thankyou everybody. Really appreciate your replies and advice.
Seems that was one of the better mistakes I've made.
Cheers
Jeremy
Seems that was one of the better mistakes I've made.
Cheers
Jeremy