[tomb]

Quote:

Thanks Tomb.
 
I was just inquisitive to see if I could hear a difference between class A and AB, but I guess it'd need to be insanely loud to get enough current flowing to pull it out of class A. I'll try loosening the panel a bit. It goes in a little way, just not all the way down - though it feels like it would if I gave it the beans with a spanner or something.

Are you using the finishing washer?  That thing is thick and tapered - it's easy to recognize.  If you're trying to screw the ferrule in without it, I'm not sure the threads go that deep.  Just a thought ...
 
 

 

[jdkJake]

Nice build TomForshaw! 
 
The miniMAX is a great little amp that continues to delight. I pulled mine out last night after a lengthy absence. I had forgotten how good it can sound. A fun night of listening for sure.
 
Enjoy your amp, I know you will! 

 
 
BTW: That tube picture turned out great. Nice shot!

 

[Ikarios]

Bringing this thread back up from the depths because I just received my MiniMAX and, like I've always suspected, it's one freakin' gorgeous piece of kit. TomB has really outdone himself on this one with the custom Lansing case (I know, I'm late to the party). I'll have to read through some of the the thread to get an idea of what biasing is all about, and how to go about swapping tubes if I need to.

 

[the_equalizer]

Have fun building the MiniMAX, Aflac. It's as fun to build as it is to listen to. I absolutely love mine!

 

[Ikarios]

Quote:

Have fun building the MiniMAX, Aflac. It's as fun to build as it is to listen to. I absolutely love mine!

I should mention that I bought mine used on the FS Forums, so it's pre-constructed... so I miss out on the building experience I don't have time to solder at school anymore however and I don't have access to a decent iron at home anymore, so maybe it's for the best. I guess I won't have to deal with biasing (which looks somewhat complicated) so that's a plus.
 

 

[jdkJake]

Congrats on the purchase.
 
Biasing the tubes is straightforward. You will have to most likely re-bias every time you roll a set of tubes. BTW, even biasing the BJT's is not too bad, you just have to remove the board from the case.
 
I would suggest you at least verify the tube bias. The BJTs being out of bias is a bit more subtle. I bought mine pre-built as well (from Whiplash) and the BJT bias was quite a bit lower than optimal. Everything being "in spec" just brings out all it has too offer.

 

[berserkir]

 
Phew, finished my build. Thanks to TomB for great service & product.
This one is with 1000&470 uF Silmics at soundpath and 0.22uF Vit-Q.

 

[tomb]

Another MiniMAX lives!

 
That's a very nice DIY-enclosure implementation.  You don't see that very often with a MiniMAX PCB, since the "normal" build uses the Beezar/Lansing custom case.

 

[tomb]

Just an FYI, but the MiniMAX is now laser-etched with a new design on the endplates:


No more silkscreen that might rub or scrape off while you're DIY-ing all the wiring and connectors in the back.  The etching is absolutely permanent (and more detailed!)  The knob is very slightly smaller in diameter, too.  I think it makes for a neater package.

 

[Yaka]

do they just replace the old ones? and can we buy just the plates?

 

[tomb]

Quote:

do they just replace the old ones? and can we buy just the plates?

Yes and No.  If there's some sort of demand for just new plates on existing MiniMAXes, I might consider selling them separately - after ordering another manufacturing run, anodizing them, and then having them laser-etched.  Naturally, that's quite a hurdle.  So, the intent is just that people who buy MiniMAX kits from now on will get the updated plates.  There are no extras.
 
Cars have major style changes every few years, amps can too, can't they?

 

[vixr]

Quote:

Yes and No.  If there's some sort of demand for just new plates on existing MiniMAXes, I might consider selling them separately - after ordering another manufacturing run, anodizing them, and then having them laser-etched.  Naturally, that's quite a hurdle.  So, the intent is just that people who buy MiniMAX kits from now on will get the updated plates.  There are no extras.
 
Cars have major style changes every few years, amps can too, can't they?

which just made my original un-built Mini a collectors item...

 

[Za'afiel]

Nice new panels there tomb. Looking forward to more refreshing updates on the MiniMAX.
 

 

[lordearl]

How does this amp sound with low impedance headphones?  I have a pair of KRK KNS8400 (36 ohms) which are just waiting to be paired with a hybrid amp......

 

[tomb]

Quote:

How does this amp sound with low impedance headphones?  I have a pair of KRK KNS8400 (36 ohms) which are just waiting to be paired with a hybrid amp......

Well, I can't tell you about those specific headphones, but the MiniMAX is designed to handle both low-impedance and high-impedance headphones.  It can pulse 50-75 ma Class A current (depending on bias setting) without sending the output transistors into a switching mode.  At the same time, the tubes and power supply give it a potential 13.5V swing in voltage to handle high-impedance.  I would recommend that you use 12FK6 tubes for low impedance, though (there are three total tube types that can be used with the MiniMAX).  The 12FK6's are the lowest gain tubes and that will allow more current for a given voltage with a low-impedance load.