[manaox2]

What hookup wire is recommended for the Max from Navships? And is there any other wire that anyone recommends? Also, what heatstrink in the case of tombstoning? I may have to borrow a blowdryer...

 

[jarensberg]

Quote:

Originally Posted by Marzie /img/forum/go_quote.gif Anyone have any extra superbright blue or violet LEDs for the tube lights? I didn't order them and if anyone has some or a source to get some fast (I will be checking my local place on the weekend) I am all ears! Mike

I have some extra blue LEDs if you're interested. Just PM me your address and I'll send you a couple.
Attachment 3281

 

[tomb]

Quote:

Originally Posted by slowpogo /img/forum/go_quote.gif I'm using a 1 amp Triad wall wart, with my BJT Max. Would there be any audible advantage to using one of the larger Beezar wall warts, or is it just more juice that my amp wouldn't use?

As stated earlier, around 750 ma is probably plenty for any BJT MAX at 50-60ma bias. 1 amp gives more of a safety margin.

You probably don't want a walwart's transformer loaded to more than 2/3 of its rating - 1/2 is even better. 1 Amp is typically plenty of headroom for a typical MAX. I made current measurements early in the MAX development and reported them in the original design thread over on DIYForums.org. Typical current draw at 50ma bias is about 450ma. So, a 0.75 to 1A walwart gives you 2/3 to 1/2 rating on the walwart.

When you get into very high biases or powering a MOSFET MAX, then that cushion disappears rather quickly. You can get core saturation and the transformer may vibrate/buzz, make more power noise, and generally speaking, just mess up the quality of the power.

I suspect that may still be going on with Joneeboi's MAX since he's complaining about his walwart buzzing and vibrating. He was one of the early builders and had trouble blowing up a couple of walwarts. So, there's probably something still going on with his MAX, but he's been listening to it for quite awhile now - maybe we should leave well enough alone.

We'll have to see if the buzzing of his walwart gets intolerable.

 

[tomb]

Quote:

Originally Posted by manaox2 /img/forum/go_quote.gif What hookup wire is recommended for the Max from Navships? And is there any other wire that anyone recommends? Also, what heatstrink in the case of tombstoning? I may have to borrow a blowdryer...

I use the 22ga Navships exclusively. However, be sure to compare among what he has and get the thinnest. I wasn't paying attention once and got some white that was very thick and stiff. John always lists the diameter of his wire, so that helps. IMHO, anything close to 0.05 inches in diameter or less is just fine.

Unfortunately, he hasn't had much 22ga to pick from lately. As I write this reply, he has four listings for 22ga, but two of them are twisted pair. The other two are OK for diameter (0.047 in.), but are some odd color arrangements: white-red and white-brown-violet. He's had much more than that in the past.

EDIT: for heatshrink, I think the 3/32" is the stuff I use most. Most heat shrink has a 2 to 1 shrinkage. You can use that to size for long lengths of wire. Since we're usually trying to cover up a wire/lug/solder-blob joint, though, a much larger size is often needed.

 

[fault151]

I received some new valves today for my millet. I now have 12fk6 and 12 ae6. Which is th recommended valve for the millet? At the minute i have a different model number of tube installed that cam with the amp.

 

[tomb]

Quote:

Originally Posted by fault151 /img/forum/go_quote.gif I received some new valves today for my millet. I now have 12fk6 and 12 ae6. Which is th recommended valve for the millet? At the minute i have a different model number of tube installed that cam with the amp.

The Millett MAX, as with the rest of the Millett line, can use three tube types: 12AE6/A, 12FM6, and 12FK6. The 12AE6/A has the most gain and bass slam, whereas the 12FK6 has the least gain with more detail and high end. The 12FM6 are between the other two in gain and in sound characteristics. It's up to you to decide which one you want.

Sometimes people suggest the 12FK6 for Grados, for instance, because of its low relative gain and high-end detail. However, just as many recommend the 12AE6 for Grados, because it adds quite a punch and bass slam that helps to fill-in the Grado's preceived deficiencies. Other headphones are different, of course, it all depends on what you want.

Note that the tube bias is not similar at all with the three types of tubes, so you need to re-bias if you switch tube types. You should do that in any case - even with new tubes within the same type - but the bias is different enough between the 12AE6 and the 12FK6 that the amp may not even work if you don't re-adjust the bias. Yours has those tip jacks in the back, so re-bias should be a piece of cake.

 

[pinkfloyd4ever]

it's a matter of personal preference really, but the differences have been discussed several times recently http://www.head-fi.org/forums/f6/new...ml#post3986737

 

[tomb]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif it's a matter of personal preference really, but the differences have been discussed several times recently http://www.head-fi.org/forums/f6/new...ml#post3986737

Wow - you're really watching!

 

[fault151]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The Millett MAX, as with the rest of the Millett line, can use three tube types: 12AE6/A, 12FM6, and 12FK6. The 12AE6/A has the most gain and bass slam, whereas the 12FK6 has the least gain with more detail and high end. The 12FM6 are between the other two in gain and in sound characteristics. It's up to you to decide which one you want. Sometimes people suggest the 12FK6 for Grados, for instance, because of its low relative gain and high-end detail. However, just as many recommend the 12AE6 for Grados, because it adds quite a punch and bass slam that helps to fill-in the Grado's preceived deficiencies. Other headphones are different, of course, it all depends on what you want. Note that the tube bias is not similar at all with the three types of tubes, so you need to re-bias if you switch tube types. You should do that in any case - even with new tubes within the same type - but the bias is different enough between the 12AE6 and the 12FK6 that the amp may not even work if you don't re-adjust the bias. Yours has those tip jacks in the back, so re-bias should be a piece of cake.

Ok cheers, at the minute i have the fm6 installed. It came with them. i Might change them for the 12ae6, i love bass! If i install them, when bias levels do i need it to be set to? Could you give me the details for all the figures i need to set it to please. I dont wanna **** it up.

Thank you.

 

[Migroo]

Bit of an update for tonight.

Just waiting for the insulators for the heatsink chips now

 

[tomb]

Quote:

Originally Posted by fault151 /img/forum/go_quote.gif Ok cheers, at the minute i have the fm6 installed. It came with them. i Might change them for the 12ae6, i love bass! If i install them, when bias levels do i need it to be set to? Could you give me the details for all the figures i need to set it to please. I dont wanna **** it up. Thank you.

Well, correct me if I'm wrong, but we set your bias earlier at 13.5VDC (your supply voltage is 27VDC).

The thing is, each of the Millett tubes should be biased at that same value: one-half of the supply voltage. What's different is that the trimmers will need to be turned to a different position to attain that value. So, after changing tubes, plug your DMM into the appropriate tip jacks - one probe in the center ground tip jack and the other probe in the immediately adjacent tip jack, on the right for the Right channel tube and on the left for the Left channel tube.

Then turn the appropriate trimmer to adjust the bias. It will never be at 13.5 if you've replaced tubes to a different type, so watch the DMM as you turn the trimmer - you'll be able to quickly tell which way to turn it and how far. If the trimmers were installed in a standard fashion, clockwise will raise the bias voltage and counter-clockwise will lower it.

 

[Marzie]

Ok, if this has been discussed elsewhere in the thread, someone let me know, but I am testing the db bias and right away I get about 350 mv (and it goes up from there) on both sides. Any suggestions?

EDIT: More info, I turned them (and all trimmers) down all the way before turning it on, and only bumped it to see the values.

 

[xnothingpoetic]

I just replaced 18 caps today with zero problems! (Rubycons in the back and wimas across the board with VitQ's up front and kept the 4 ES's the way they were)

Hurray for me!

Bass is now crazzy deep with good punch and the midrange is to die for!

 

[tomb]

Quote:

Originally Posted by Marzie /img/forum/go_quote.gif Ok, if this has been discussed elsewhere in the thread, someone let me know, but I am testing the db bias and right away I get about 350 mv (and it goes up from there) on both sides. Any suggestions? EDIT: More info, I turned them (and all trimmers) down all the way before turning it on, and only bumped it to see the values.

Well, that's not good.

First thing, make sure that you are measuring the bias from the proper test points. Look at the photographic key on the MAX website:
MAX Setup and Bias Settings
When measuring the DB bias, you are only trying to measure the voltage (and thus convert to milliamps) across the DB output resistors - RB10L/R and RB11L/R. You do that by putting one probe in TA2L and either TB1L or TB2L for the Left Channel DB. For the Right Channel DB, that's putting one probe in TA2R. The other probe then goes in TB1R or TB2R.

It's quite possible you'll read some strange voltages if you have one probe in Ground.

Check that first.

 

[Marzie]

Well I went back to retest because the site said "figure out whether the trimmers are operating correctly" so I went to check the resistances. I checked it initially and saw 1.2 ohms. at first I thought they might be bad, but 2 bad trimmers? So I started to adjust them and as I turned the trimmers, well I noticed something strange, I turned the trimmers "up" (clockwise) and saw the resistance increase...? Well I went and reread the site and discover that clockwise is down, not what I expected... Off to try again...

EDIT: I know the up, down terminology may be confusing, but I expected the mV to go "up" as I turned the trimmer clockwise, not the inverse... anyway, I'm gonna go change this.