[n_maher]

Quote:

Originally Posted by amb Not Nate here, but my STEPS for the Millett has 120 ohms and 2K ohms for R3/R4 and the output adjusted to 27VDC. I am using the Amveco 70062 25VA transformer and the LM338T regulator which are a bit of overkill but I wanted to be able to use the same supply for other amps too. I am also using another identically-configured STEPS for use with my M³.

Mine is similar to AMB's but I used the 70052 15VA transformer and LM317 regulator. I'd have to recheck my notes to see what resistors I used but my guess is that it was 100 ohm and 2.0K.

HTH,

Nate

 

[Blooze]

Please excuse this noobie question.

I was thinking I'd like to put a rotary on/off switch on my Millet. I'm not sure which to use since most of the rotarys are 2 pole with many positions and it seems like a SPST would be the one to get. Does anyone know where I can get a suitable switch that will work?

 

[derek_lukasik]

Hi,

Just got my board and started the build last night. One thing I noticed that I haven't been able to figure out... There is a position on the board labelled D3 with markings for a diode on the board. Yet, I have not been able to find any reference as to how to populate this position. It looks like the leads coming off of it don't go anywhere??? Anyone know what this is for?

D3 is located between C1 and C10L right in the center of the board. On the opposite side of the pot.

Thanks,

Derek

 

[n_maher]

Derek,

I'll ask Drew, that position didn't used to be there as far as I can remember.

I'll get back to you ASAP.

Nate

 

[n_maher]

Update, just leave D3 unpopulated. It only exists on the most recent batch of Millett boards and serves no purpose. It's already been taken back out

.

Sorry for the confusion.

Nate

 

[derek_lukasik]

OK. Thanks a lot for looking into that.

Derek

 

[n_maher]

That's what I'm here for

.

 

[Nisbeth]

FWIW, if anyone wants an in-line diode to protect against reverse polarity damage it is possible (with a tiny bit of force...) to fit an 1N400x across the switch pads on the board. You then have to fit the power switch directly on the supply leads of course, but I always do that anyway so it wasn't really a problem for me

/U.

 

[derek_lukasik]

Just finished up my Millett. Here are a couple of pics. I've decided I'm the worst case builder in the world.... Listening begins in earnest tonight!!! Can't wait.

Derek

 

[Blooze]

Quote:

Originally Posted by derek_lukasik Just finished up my Millett. Here are a couple of pics. I've decided I'm the worst case builder in the world.... Listening begins in earnest tonight!!! Can't wait. Derek

Looks pretty dang good to me! Let us know how she sounds.

 

[amb]

Quote:

Originally Posted by Nisbeth FWIW, if anyone wants an in-line diode to protect against reverse polarity damage it is possible (with a tiny bit of force...) to fit an 1N400x across the switch pads on the board.

There is no need to do that because the self-resetting fuse PF1 and the overvoltage protection diode D1 already perform this function. If the supply voltage is higher than what D1 is rated for, then D1 begins to conduct and acts like a crowbar and will cause PF1 to open. If the supply is connected with the wrong polarity, D1 becomes forward biased and will also acts as a crowbar and cause PF1 to open.

 

[derek_lukasik]

Well, two solid nights of listening and I love it! Man, this thing is really smooooth. I'm a Grado fan, and I think the Millett really complements the Grados well. Smooths out the brightness really well. The midrange on this thing is really beautiful as advertised. Haven't really had much experience with tubes until now. For this application, I think they're great.

Thanks to all of you folks out there for making this possible! Who woulda thunk that a software guy could build a decent piece of hardware? V=IR is about as much as I can handle...

Back to listening....

Derek

 

[derek_lukasik]

Speaking of my lack of EE knowledge....that reminds me....a quick question. So, if I wanted to figure out how much load my cans put on the amp, how would I go about it? Is the bias voltage the one to use to calculate the current? For my Millett, I have the bias at 16V or so I think. So, the max current draw would be something like 500mA for 32ohm Grados. Is that right? And the power would be 8 watts (500mA *500mA * 16V * 2)? That seems way too high for some reason...

Thanks,

Derek

 

[jerb]

A quick skim didnt bring up the awnser I needed, what tube is the prefered favorite? I've seen the 12AE6A, 12FM6, and 12FK6 floating around so what is everyones favorite?

 

[ottopig]

Answers to the last two posts:
Quote:

Originally Posted by derek_lukasik ...So, the max current draw would be something like 500mA for 32ohm Grados. Is that right? And the power would be 8 watts (500mA *500mA * 16V * 2)? That seems way too high for some reason...

and
Quote:

Originally Posted by jerb A quick skim didnt bring up the awnser I needed, what tube is the prefered favorite? I've seen the 12AE6A, 12FM6, and 12FK6 floating around so what is everyones favorite?

and a lot more can be found on amb's site at http://www.ibiblio.org/tkan/audio/millett.html

See the Comments section for the current load at 32ohm and all the tube selection and bias setting info. Ti's posted boatloads of good info for all of us building and tweaking the M-H. You might also be interested in the substitution of OPA551PA for BUF634P and the discrete buffer development work being led by steinchen with input from amb and others at http://www.diyforums.org/phpBB2/view...r=asc&start=30

I don't mean to direct people away from this site and hope to see your comments back here. Cheers,

ottopig