[MiRaCL]

Hello

Just finished my Millett Hybrid,and it sounds great.
Maybe a litt to much bass with the DT-770pro's i use,but it's ok.

Any way to improve the sound?

Im thinking about recabling the Dt-770's for a start.

Stacking the Buffers (BUF634) what's the point? And if it improves the sound,how do i do it, just solder a BUF634P's on the BUF634P's aldready in the amp?

Any other things i can do?

 

[BradJudy]

If you stack buffers, you'll also need to make a change to the resistor that sets the buffer bandwidth, IIRC.

 

[thedoctor]

then there's the OPA551 and diamond buffers if you're looking for something different.

 

[[AK]Zip]

Diamond buffers and you can try different tubes.

-Alex-

 

[bperboy]

Personally, I've got the opa551's in my Millett, and I just finished recabling my headphones. I think it sounds awesome, but then, everything I do in DIY is a new experience so I don't have anything to base it off of.

 

[seanohue]

Does anyone have a comparison of the OPA511 and BUF634?

 

[nikongod]

you can make a direct coupled millet (basically a soha on a millet board with daughterboard), and a millet with no caps in the signal path (uses same daughetboard, with film caps jumpered, and VERY carefull bias adjustments.)

you can also add a resistor divider in front of the buf-634's to dump off some gain sort of. it gives you more movement of the knob anyways...

edited:
you can also experiment with using diferent (and especically none) bypass film caps, that parallel every electrolytic ont eh millet board. my opinion is that they are not optional, but simply better left out.

 

[NeilR]

Quote:

Originally Posted by nikongod you can make a direct coupled millet (basically a soha on a millet board with daughterboard), and a millet with no caps in the signal path (uses same daughetboard, with film caps jumpered, and VERY carefull bias adjustments.)

Ummm.... you have go into a little more detail there. How do you get rid of the plate voltage without a cap somwhere in the path?

 

[nikongod]

Quote:

Originally Posted by NeilR Ummm.... you have go into a little more detail there. How do you get rid of the plate voltage without a cap somwhere in the path?

click for thread

not the safest thing you can do with a driver, but it can be done.

 

[NeilR]

Quote:

Originally Posted by nikongod click for thread not the safest thing you can do with a driver, but it can be done.

Nikongod, a couple of comments....

1) Drawing designs on a napkin is supposed to be a figure of speech; you're not supposed to really do that and post it on the net

At least there was no ketchup on it.

2) More seriously, your design is such (if my quick read is correct) that any drift in bias translates 1:1 into DC offset. I know my Millet pretty well and I know a little about 50 year old vacuum tubes, which were never intended to be precision instruments in their youths. I think that is ultimately doomed to failure.

But it is a very neat thought experiment. Just not an experiment I would subject my HD-650's to, unless I had a voltmeter display on the front panel and even then.... I'd want to have a backup pair of Senn's, which i do not

 

[MiRaCL]

Quote:

Originally Posted by bperboy Personally, I've got the opa551's in my Millett, and I just finished recabling my headphones. I think it sounds awesome, but then, everything I do in DIY is a new experience so I don't have anything to base it off of.

Yea,im new to DIY to,so i don't know if the MH sounds good.

Since N_Maher was out of DB boards for the time beeing, i can try to stack the buffers.
How exactly do i do this?

 

[thedoctor]

Quote:

Originally Posted by MiRaCL Yea,im new to DIY to,so i don't know if the MH sounds good. Since N_Maher was out of DB boards for the time beeing, i can try to stack the buffers. How exactly do i do this?

Quote:

The BUF634 buffer is stackable. This means you can literally stack them on top of each other and solder their pins together to run multiple buffers in parallel.

taken from here.