[drewd]

The latest iteration of the board.

Regarding board size versus tube size, this board is the same size as a PPA circuit board.

I've tweaked the routing a little bit, changed the bias adjustment pots to Bourns and added an extra set of inputs closer to the volume control. Also added mounting holes for those who want to use a non-Eurocard case.

Board layout

Rendered PCB

As usual, suggestions, criticism and complaints are welcome!

-Drew

EDIT: Fixed mangled links

 

[MisterX]

Nice work.... chances of replacing the BUF634 with Intersills?

 

[comabereni]

Quote:

Originally Posted by drewd Regarding board size versus tube size, this board is the same size as a PPA circuit board.

It looks nice. How big is the PPA circuit board?

-coma

 

[MisterX]

6.3 × 3.925" or 160 ×100mm

 

[comabereni]

Neat--so it's almost an inch narrower and a half-inch shorter. Good work.

It looks like most of the entire left side of the board is just for the pot. It would be neat if there was a way for those of us still wanting to compress the board size further and move the pot off the board and between the tubes to cut the pot end of the board off completely (appx. 1/5 of the board length) and still have some pads to solder the pot to. Only that 1K resistor (??) and 220UF_16U cap (??) are sitting in the way (correct me if I'm not identifying these properly). Anyway, would it even be possible if the pot were moved to the left a little for the resistor to be turned 90-degrees and maybe an optional set of pot pads to be located in-board a little? If so, the board length could maybe be reduced another inch for those of us not planning to use a standard enclosure. The "Team Head-Fi" printing could be moved to right/back end of the board so it wouldn't get cut off.

Just say "no". (

) It would be pretty neat if this was designed to permit an alternative PCB/case configuration, but I'm not expecting anything. There are always compromises and this is better than the original at around half the price.

Again, good job.

-coma

 

[drewd]

Quote:

Originally Posted by MisterX Nice work.... chances of replacing the BUF634 with Intersills?

You are an evil, evil man.

 

[drewd]

Added pads for off-board pots. Moved some components on the left side of the board a little bit to make room for the pads and associated extra trace.

Board render

Board image

I'm sleepy...

 

[comabereni]

**AWESOME**

 

[individual6891]

Quote:

Originally Posted by comabereni It looks like most of the entire left side of the board is just for the pot. It would be neat if there was a way for those of us still wanting to compress the board size further. -coma

The point is keeping the board size eurocard isn't it? 160x100mm ..so that it can fit standard eurocard enclosures as mentioned.

Regarding the pot pads - you can easily mount an offboard pot simply from the ALPs pot's pads. It's not difficult looking at a datasheet to figure the pinouts - why complicate the circuit further still? You don't see external pot pads in other designs..I prefer post #61 layout.

Quote:

Originally Posted by drewd I'm sleepy...

It's looking pretty impressive so far, good work ... get some sleep

 

[comabereni]

Quote:

Originally Posted by individual6891 The point is keeping the board size eurocard isn't it? 160x100mm ..so that it can fit standard eurocard enclosures as mentioned. Regarding the pot pads - you can easily mount an offboard pot simply from the ALPs pot's pads. It's not difficult looking at a datasheet to figure the pinouts - why complicate the circuit further still?

Hey now, let's not undo progress

. This last revision permits some radical custom orientation and enclosure options for those of us with a bandsaw and not afraid to use it.

Doesn't #67 fit in a eurocard enclosure and do everything #61 does anyway?

-coma

 

[individual6891]

It further complicates the circuit by adding unnecessary pads.. How many other PCB layouts have you seen with external pot pads in addition to it's PCB component?

Quote:

This last revision permits some radical custom orientation

I wouldn't exactly call it radical, you're simply slicing 1 inches of board space, and sure there are cases that maybe (I wouldn't know why though) accomodate 100mm x 135mm PCBs (?!?), but how many have you found?

 

[n_maher]

At this point I think that we should hold the board design where we've got it unless there are concerns about the circuit layout. Component and options wise I think we've acheived what was the original goal of this project. Mainly to get rid of all the board mounted components (save for the pot) and add some increased functionality to the original design. There isn't going to be any single design that deals with everyone's desires

. If a lot of folks are wanting a tweaked, hotrodded MH than I think it would make sense for them to pursue this on their own. I'd really like to keep this version as true to the original design as possible. If we decide to go through another round of tweaks I'll let everyone know.

For now Drew and I have begun talking about how we're going to handle the prototype testing phase. I'll update this thread as more information becomes available. My sincere hope is to have this amp built alongside an M3, PPA V2 and Dynalo for comparisons. That may take a minor miracle though.

Thanks to everyone for their input, I for one am really pleased with the most recent board layout. Most of all, thanks again to Drew for volunteering his time and knowledge.

Nate

 

[skyskraper]

eurocard is nice but why not give options

who knows what people want to do with the circuit

 

[individual6891]

Quote:

Originally Posted by n_maher At this point I think that we should hold the board design where we've got it unless there are concerns about the circuit layout. Component and options wise I think we've acheived what was the original goal of this project. Mainly to get rid of all the board mounted components (save for the pot) and add some increased functionality to the original design. There isn't going to be any single design that deals with everyone's desires . If a lot of folks are wanting a tweaked, hotrodded MH than I think it would make sense for them to pursue this on their own. I'd really like to keep this version as true to the original design as possible. If we decide to go through another round of tweaks I'll let everyone know. For now Drew and I have begun talking about how we're going to handle the prototype testing phase. I'll update this thread as more information becomes available. My sincere hope is to have this amp built alongside an M3, PPA V2 and Dynalo for comparisons. That may take a minor miracle though. Thanks to everyone for their input, I for one am really pleased with the most recent board layout. Most of all, thanks again to Drew for volunteering his time and knowledge. Nate

That sounds cool.

Just from curiosity, is there anyone from USA willing to distribute some tubes/sockets to europeans? We're still having difficulties with some stock (nice source though nisbeth, but very very expensive!).

 

[comabereni]

Quote:

Originally Posted by individual6891 It further complicates the circuit by adding unnecessary pads.. How many other PCB layouts have you seen with external pot pads in addition to it's PCB component? I wouldn't exactly call it radical, you're simply slicing 1 inches of board space, and sure there are cases that maybe (I wouldn't know why though) accomodate 100mm x 135mm PCBs (?!?), but how many have you found?

I agree this last revision was a step beyond the necessary, but I'm grateful for it. It opens up custom size, orientation and enclosure options. I personally see no reason to go back to an earlier version unless the earlier version is better than this last one.

In fact, I'm buying Drew dinner as soon as he sends his PayPal address (thanks!)

.

-coma