[Juaquin]

The current SSMH BOM uses some pretty high-quality parts. You could pay 2-5x the price for "boutique" parts that would only give you maybe a 5% increase in quality. Boutique parts would be things like SoniCaps or Mundorf caps, black gates (no longer available), etc. The resistors used in the SSMH are pretty much top-of-the-line as it is, so nothing to do there. You could switch out the pot for an Alps RK27 - in fact, that is probably worth the extra cost (the pot in the default BOM is good but not amazing). You could even use a stepped attenuator instead of a pot.

Really, if you're looking to upgrade the SSMH you'd be better off just building a higher-end amp like the Mini-Max. You'll get more for your money that way than you would buying "boutique" parts.

 

[the_equalizer]

So, what do you guys think? This is the first draft schematic for the 12AU7 version of the Millett "Starving Student" Hybrid headphone amplifier.

cheers!

 

[hss3]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif Am I correct in assuming it's a double sided board? cheers!

Yes it is.

Wow, everyone on here is so helpful. Thanks for the above schematic... seems right to me.

 

[Juaquin]

Looks good to me. Might want to add a note somewhere that it's a modification so people don't get confused.

 

[the_equalizer]

Quote:

Originally Posted by hss3 /img/forum/go_quote.gif Yes it is. Wow, everyone on here is so helpful. Thanks for the above schematic... seems right to me.

Well, your PCB drawing is certainly very helpful! So far it looks great!

Quote:

Originally Posted by Juaquin /img/forum/go_quote.gif Looks good to me. Might want to add a note somewhere that it's a modification so people don't get confused.

Good point. I edited the post to add that clarification and I'll add it to the schematic. Thanks !

 

[blitzpirate]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif Sounds like the potentiometer pins that connect to the ground plane are not correctly soldered, particularly the pin corresponding to the right channel. Check those solder points. Getting the solder to really flow in those takes quite a bit of heat, you'll need to apply your soldering iron for some 2 or three minutes until the ground plane heats up and the solder flows. Problem is that you don't want to heat the pot pin as much, just the pad. So I'd suggest removing the solder, applying the iron to the pad long enough so that the solder flows, then apply the iron for some seconds to the pot pin too and then feed in the solder. cheers!

hey thx for the help, but i did a noobie mistake and put to much solder and it went through the pins and connected on the other side. haha now do you have any tips on how to take the potentiometer off or how to disable the volume part completely because i can just use my dac for changing the volume? and if i cant do it, can anyone fix it for me if i ship it to them and pay for return shipping plus what you want to charge me for fixing it?

 

[m11a1]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif So, what do you guys think? This is the first draft schematic for the 12AU7 version of the Millett "Starving Student" Hybrid headphone amplifier. cheers!

Looks great!

By the way, I have a question regarding the SSMH. Do you think it's possible to make a balanced SSMH. So it would be 2 boards for each channel? Or am I just crazy here....

 

[tomb]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif So, what do you guys think? This is the first draft schematic for the 12AU7 version of the Millett "Starving Student" Hybrid headphone amplifier. </snip>

Looks great!

 

[the_equalizer]

Quote:

Originally Posted by blitzpirate /img/forum/go_quote.gif hey thx for the help, but i did a noobie mistake and put to much solder and it went through the pins and connected on the other side. haha now do you have any tips on how to take the potentiometer off or how to disable the volume part completely because i can just use my dac for changing the volume? and if i cant do it, can anyone fix it for me if i ship it to them and pay for return shipping plus what you want to charge me for fixing it?

Well, that's no mistake. That actually means you did a great job of soldering.

Maybe you could try posting some clear pics of the board underside and topside in the area where the pot is installed? Just to be sure before advancing any definite advice.

Quote:

Originally Posted by m11a1 /img/forum/go_quote.gif Looks great! By the way, I have a question regarding the SSMH. Do you think it's possible to make a balanced SSMH. So it would be 2 boards for each channel? Or am I just crazy here....

It would require 1 board per channel, so four tubes, 4 MOSFETs, 2 PSUs (unless you're using a 1 amp PSU already),etc.

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Looks great!

Thanks ! I think I'll add the updated value for the electrolytics and the optional parts from the new schematic and that's it!

cheers!

 

[timmyGCSE]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif So, what do you guys think? This is the first draft schematic for the 12AU7 version of the Millett "Starving Student" Hybrid headphone amplifier. image cheers!

nice but am I correct in saying you've used the original design and not this one?
http://www.diyforums.org/SSMH/schema...MH-origPCB.gif

 

[tomb]

Quote:

Originally Posted by timmyGCSE /img/forum/go_quote.gif nice but am I correct in saying you've used the original design and not this one? http://www.diyforums.org/SSMH/schema...MH-origPCB.gif

That's a good question and one I'm not sure how to answer. I guess it's up to the_equalizer, since the 12AU7 mods are his. The image you reference here is Dsavitsk's mods for the SSMH PCB. These mods definitely made the amp sound better. However, without a PCB, it's back to P2P and maybe it's better to reference the original schematic and let those who investigate further add the PCB mods.

 

[timmyGCSE]

from what I can gather..the schematic above is defo the original and not Dsavitsk's mods. In the original 12AU7 post the_equalizer made with a picture of the P2P wired tube sockets of his 12AU7, it was of the modified version and that threw me when I was comparing it to the original schematic lol, but just then it threw me again because he schematic is back to the original haha.

Anyway yes I don't want to tread on equalizers toes, I started hand sketching a PCB design for the modded version yesterday, but it will be crap and I will spare my own embarressment by not showing anyone haha! but I want to make it myself and that just to prove to myself I can do it

 

[ezzieyguywuf]

Juaquin: thanks, thats the kind of answer I was looking for. Now that you've mentioned the minimax and I've checked it out, I don't know which direction I want to go Of course, if I went with the mini it'd have to be sans enclosure, as its way outa my price range as it is.

 

[timmyGCSE]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif It would require 1 board per channel, so four tubes, 4 MOSFETs, 2 PSUs (unless you're using a 1 amp PSU already),etc.

I was thinking of this! would there be any advantage to doing it?

 

[the_equalizer]

Quote:

Originally Posted by timmyGCSE /img/forum/go_quote.gif nice but am I correct in saying you've used the original design and not this one? http://www.diyforums.org/SSMH/schema...MH-origPCB.gif

Quote:

Originally Posted by tomb /img/forum/go_quote.gif That's a good question and one I'm not sure how to answer. I guess it's up to the_equalizer, since the 12AU7 mods are his. The image you reference here is Dsavitsk's mods for the SSMH PCB. These mods definitely made the amp sound better. However, without a PCB, it's back to P2P and maybe it's better to reference the original schematic and let those who investigate further add the PCB mods.

Quote:

Originally Posted by timmyGCSE /img/forum/go_quote.gif from what I can gather..the schematic above is defo the original and not Dsavitsk's mods. In the original 12AU7 post the_equalizer made with a picture of the P2P wired tube sockets of his 12AU7, it was of the modified version and that threw me when I was comparing it to the original schematic lol, but just then it threw me again because he schematic is back to the original haha. Anyway yes I don't want to tread on equalizers toes, I started hand sketching a PCB design for the modded version yesterday, but it will be crap and I will spare my own embarressment by not showing anyone haha! but I want to make it myself and that just to prove to myself I can do it

Guys, guys! as I said in my previous post: I'll add the higher value for the electrolytics and the optional parts (the highlighted ones) from the new schematic

@timmyGCSE: If you read at the top of Dsavitsk's schematic you can see that the highlighted parts are optional; they're not essential to the operation of the circuit but, as TomB mentions, improve the way it sounds.

cheers!