[regal]

I just tried these 2SC3421/1358's from Beezar.com and these are fantastic with Grado's. Much better than the ebay 2238/968's they replaced. I really recommend giving these a try. Thanks Tomb for suggesting these as I would have written them off based on Steinchen's ratings.

 

[Beefy]

Quote:

Originally Posted by regal /img/forum/go_quote.gif Much better than the ebay 2238/968's they replaced.

Reputable seller? Otherwise, good chance they were fake.

 

[MASantos]

Going back to the powering speakers topic, what would be needed to enable the mosfet max to deliver around 5-10W?

I guess bigger heatsinks, higher voltage for the output stage? I would love to see a hibrid power amp, a MH meets B22 sort of thing!

 

[tomb]

Quote:

Originally Posted by MASantos /img/forum/go_quote.gif Going back to the powering speakers topic, what would be needed to enable the mosfet max to deliver around 5-10W? I guess bigger heatsinks, higher voltage for the output stage? I would love to see a hibrid power amp, a MH meets B22 sort of thing!

You might ask BoilerMakerFan. He and cetoole have had extensive conversations on applying a MAX to power speakers.

 

[Beefy]

Quote:

Originally Posted by MASantos /img/forum/go_quote.gif Going back to the powering speakers topic, what would be needed to enable the mosfet max to deliver around 5-10W? I guess bigger heatsinks, higher voltage for the output stage? I would love to see a hibrid power amp, a MH meets B22 sort of thing!

Quote:

Originally Posted by tomb /img/forum/go_quote.gif You might ask BoilerMakerFan. He and cetoole have had extensive conversations on applying a MAX to power speakers.

My simple answer would be to go balanced

 

[MASantos]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif My simple answer would be to go balanced

That would double it quite easily! Add a sigma22 bipassing the millettmax power supply, off board heatsinks and quite easily reach 3W. But then then the parts cost would probably allow for a better design, specific for low power speakers!

 

[BoilermakerFan]

The MHM and MOSFET-MAX wasn't designed to be a speaker amp or built as balanced. If you want that much power you're better off with a different design. For the cost of a balanced MHM you can build a F5 which will do 25W Class A. Another $200 in PS mods and the F5 is suitable for headphone use with extremely low noise and ripple that only improves it's speaker performance. I just can't recommend a balance MHM when there are better options in the $400-$600 price range, especially for a dual role of headphones and speakers.

The MOSFET-MAX is capable of delivering about 2W to speakers as it is and with 92dB or better efficient speakers, it will be enough for "normal" listening levels and near field monitor applications. The tweaks I pursued where to raise the bias levels over 150mA (perhaps pushing to 225mA, but that really approaches the safe upper limit of 7W dissipation on a 2-1/2" heat sink and it better have lots of ventilation for good air flow). The higher bias just keels the amp in Class A longer when driving speakers. I am not changing the voltage, it stays 24Vac and a LM338 is capable of handling 5A so the PS is fine with that change. The polyfuse needs to be bumped up to 1.35A as a starting point, but it may need to go up to nearly 2A if you are really driving inefficient speakers and really putting a high demand on the PS. My speakers are 93dB/W and 97dB/W. IIRC, Colin's speakers are 91 or 92dB/W.

There are several tweaks that need to be done to the BOM, but if you're still interested, drop me a PM with your email addy and I'll detail the changes. In order to avoid confusion, I'm not going to post in this thread.

 

[redfish-bluefish]

Quote:

Originally Posted by BoilermakerFan /img/forum/go_quote.gif Because it's a full kit with all the machining/drilling on the case done for you. If you build a MOSFET-MAX, it has to go in a bigger chassis like the spec'ed Hammond and you have to mark and drill all the holes as well as order the parts from a few different places.

Gotcha.

I'll keep that in mind in making decisions, but I do have some experience with and tools for layouts, drilling etc. You are, of course, right about ordering--I've made enough mistakes on Mouser orders to know that if you don't truly know what you are looking for/at, you run a high risk of screw up. Actually, even if you do know!

I guess that I have really been approaching this from more of a "what do I want sonically" standpoint. I have a lot of confidence, but am humble enough to recognize that my electronics experience is in a totally different genre.

I very much appreciate the input.
Thanks!
1,2
red-blue

 

[funch]

Since the supply of the specified Wima cap's has dried up, does anyone here know of
either an alternate source, or a suitable replacement?

 

[Lil' Knight]

Last time I checked, Beezar still has the Wimas.

 

[funch]

Nope! They're gone too. I've got several .18uF Vitamin Q's, but it seems as though
I read somewhere that using boutique cap's in CA3/6/9 wasn't a good idea.

 

[tomb]

Quote:

Originally Posted by funch /img/forum/go_quote.gif Nope! They're gone too. I've got several .18uF Vitamin Q's, but it seems as though I read somewhere that using boutique cap's in CA3/6/9 wasn't a good idea.

I've got some more right now, but unfortunately I'm out of town until next weekend. If you can wait until then, I've have them re-listed.

I had zero'd the stock on the Wima caps so there would be enough for MiniMAX kit orders - until I received more of them.

 

[funch]

Shoulda' known 'the man' had it covered. No big rush on my part. I just noticed that
Mouser shows their next delivery is the end of June, so I went looking for a replacement.
Not much out there as a decent replacement. BTW, would .18 or .22 Sprague's work in
CA3/6/9?

 

[tomb]

Quote:

Originally Posted by funch /img/forum/go_quote.gif Shoulda' known 'the man' had it covered. No big rush on my part. I just noticed that Mouser shows their next delivery is the end of June, so I went looking for a replacement. Not much out there as a decent replacement. BTW, would .18 or .22 Sprague's work in CA3/6/9?

I would recommend staying with the Wima's, if you can wait. VitQ's make no difference at CA3 and CA6 (a waste) and they'll actually cut some of the bass at CA9.

 

[Beefy]

Is there still a Panasonic alternative from Digikey?