[eruditass]

do the brands of the tube matter? For example, 6680 can come from Sylvania, GE, TungSol, RCA.. but you only ever really hear about them with GE. Do they effect the sound as well as quality control?

second, can i use something like an old aluminum HD enclosure? How high should the enclosure be? Do they have anything from lowes or hardware stores like that? Since i'm building a SOHA i'd like the possibility of a JISBOS upgrade available and would need 3"x6" extra space in case.

also, since I may be driving some lower impedance headphones with it, is there anything I can do to reduce the gain or improve the current output? what op amps to optimize clarity, neutralness, speed, and soundstage with a 6680?

that's all i can think of, but i havn't even started building it.. this will be fun. now i just need to find myself a cheap pair of dt880's

 

[headphonejunkie]

On tubes. Every manufacturers tube will sound different from the other. The differences may be subtle or great depending on the manufacturer.On gain, I use a 100 ohm resistor on its output for my grados and that works fine for me.On tubes to use,I have found that an Amperex orange globe 12au7a from the 70's made in great britain sounds the best for my ears. A mullard may sound similar. YMMV. I have never tried a 6680.I want to try a 12au7 bugle boy but their price has stopped me. I am still waiting for that great deal on ebay.Of course, that is whats fun about tube rolling. It can get expensive though.

 

[Sathimas]

I am using a GE 6680 and a GE5963 5Star.

The GE6680 is my absolute favourite tube with my DT880.
The 5963 has more punch but less low end bass (hope you understand).
The 6680 also sounds more detailed and is less tiring than the 5963.

 

[headphonejunkie]

The amperex orange globe brings out the midrange more and has a nice warmth to it.On one song I felt I was sitting right next to the tambourine player. It was uncanny.

 

[heatmizer]

An old hard drive enclosure will barely hold the soha board. V3 soha board is 100mm wide x 118mm deep. The transformer would be tight if it fit at all. Height wise minimum is 25mm this will allow for 6-8 mm standoffs and the regulators and caps to be barely under the top with out touching. You would fine tune it by adjusting the standoffs. As far as lowes etc they would have sheet metal flat stock that you could bend yourself. If you go with Jisbos you don't need an opamp. The Jisbos can also lower the gain for low impedance phones. Some of the early builders made adapters for 2 opa551 and some made adapters with 1 opamp with 2 buf634. If you stick with opamps be aware of how you build the tube ccs. Bipolar opamps need the tube ccs laid out differently.

 

[eruditass]

thanks for your response, looks like i will order that enclosure, perhaps i will put the alienDAC inside the old hd enclosure or just order that enclosure too.

will 8.66 x 4.06 x 2.1 be big enough for jisbos if i want it?

also how important are good capacitors at C2 & C14 and C1 & C13? right now they are set to Radial Metallized Polypropylene Film as one person said that tubes is the main thing i want to worry about.

 

[eruditass]

there is nothing special about the hammond enclosures, right?

RadioShack.com - Cables, Parts & Connectors: Component parts: Project boxes: Project Enclosure (7x5x3") would be a suitable replacement?

 

[heatmizer]

That would work just not as pretty