[runeight]

BoM is changed on the website.

 

[les_garten]

Quote:

BoM is changed on the website.

Thanx Alex, Top notch as usual!

 

[ujamerstand]

One less check before mouser order reveals MJE340STUs are out of order. would 863-MJE340G be an adequate substitute? its VEBO rating is 3V rather than 5V.
 
Nevermind. Answered my own question.

 

[rbarth]

Quote:

Gentlemen, in the last week several of you have emailed me about failure conditions if one tube goes out in the hybrid.
 

How long are these tubes supposed to last?  Or is there too much variability to answer that question meaningfully?

 

[runeight]

Depending on the operating conditions, tubes last in the range of thousands of hours. Power tubes have a shorter life, preamp tubes, on average, can last longer.
 
Generally, tubes rarely die because the filament dies and stops heating the cathode. Good manufacturing tries to ensure that the filament will outlast the ability of the cathode coating to emit electrons. So, the failure mode that we're accounting for here is pretty unlikely, but possible.
 
The most common way that tubes die is that their current emissivity slowly drops. This alters the operating point conditions and, usually, the amp just starts to sound bad.
 
The other common way is that they get gassy and the getter simply can't keep up with the gas. You'll see this when the silver getter starts to turn white.
 
Another way that tubes are damaged is by applying high voltage before the heaters are warmed up. In the good old days this was handled by using tube rectifiers which caused the HV to come up slowly because the recitifier was also heating up along with the rest of the tubes.
 
With modern sand rectifiers the HV comes up almost immediately and applies voltage before the tubes are conducting. The common solution, as you all know, is to first turn on the heaters and then turn on the HV. Although we haven't discussed this much on the thread, it wouldn't hurt to power up the hybrid this way. We haven't made a big deal over it in order to keep things simple.
 

 

[paxeaxe23]

Anyone know a source for 6S4A Tubes in Germany (or anywhere in Europe)  I have only found one source and I do have a set of 4 tubes, but he charges a whopping 14 Euros each. I regularly see these tubes on eBay in the US for 3 - 4 Dollars and it looks like Pabbi1 has had fun stock piling them (well some of those photos do look great, almost as exciting as a pile of gold bars!) 
 
Still, I haven't come across a ready supply here in Europe at reasonable prices, and it is probably a good idea to get hold of at least one more set (and a matched one too, mine isn't) .  Any suggestions?

 

[rolotube]

Quote:

Well, I am completely out of anything other than (NFS) Tung Sol, so I'm no help there. You might ping one of the eBay sellers, though shipping for a single tube is always excessive. You might also ping one of the internet sellers (http://www.vacuumtubes.net/ comes to mind, or www.Tubedepot.com ), This looks like a good candidate. 
 
Pity I am chasing different glass at the moment, so doubtful I buy any more 6s4a tubes.
 
On a far happier topic, a box with 15 Stax connectors left Dallas today heading for Oz. I *think* 13 are spoken for, with Jin getting 2 (or 3), so:
 
Wink - 3
Noeb - 2
Chinsettawong - 2
Chaotic Angel - 2
Rolotube - 2
Jinh - 2 (unless you are doing two builds, then 3)
 
So, there are one or two left unclaimed, and I will leave it solely at Tony's discretion as to how they get distributed, SO, everyone ping Rolotube to arrange postage out to you, as he should see the box this time next week.
 
Should be some building frenzy about now, eh?

 
Thanks pabbi.  They will go to good homes.
 

 

[BoilermakerFan]

Quote:

Anyone know a source for 6S4A Tubes in Germany (or anywhere in Europe)  I have only found one source and I do have a set of 4 tubes, but he charges a whopping 14 Euros each. I regularly see these tubes on eBay in the US for 3 - 4 Dollars and it looks like Pabbi1 has had fun stock piling them (well some of those photos do look great, almost as exciting as a pile of gold bars!) 
 
Still, I haven't come across a ready supply here in Europe at reasonable prices, and it is probably a good idea to get hold of at least one more set (and a matched one too, mine isn't) .  Any suggestions?

I'm checking with a secret source in Europe.   Dropped him and email and sent you a PM.

 

 

[pabbi1]

Yes, PM also sent - for a known honey hole - good luck!
 
Oh, and I bought a Koss ESP-950 today (impulse buy off CL)... just a pity it has to be reterminated, so I can now see if there is the same synergy as he60 and 404LE... at the proper bias  
 

 

[BoilermakerFan]

Quote:

Yes, PM also sent - for a known honey hole - good luck!
 
Oh, and I bought a Koss ESP-950 today (impulse buy off CL)... just a pity it has to be reterminated, so I can now see if there is the same synergy as he60 and 404LE... at the proper bias  
 

Al, do you just want a whole new Stax cable?  I have one for ya'.   
 
I don't think it will quite as nice as the HE60s, especially if the custom HE60s really improve over the stockers, but I bet it will sound pretty sweet and a few mods to the 950s later can raise it up a notch too. 

 

[sachu]

I think I am now very very interested to do a direct comparison with an O2MK1 + Exstata versus a nice LCD-2 system. Had a chance to listen to an exstata i built for a friend months ago with the O2Mk1 today and I was blown away. While the Wharfie zebs edge out the O2 in some very specific areas the stat system around the O2 annhilates the wharfie zebrawoods + Liquid gold setup. The effect is similar to the LCD-2 for me. 
 
Wish I could spend some serious time with an O2 + Exstata system. Sadly the O2 wasn't mine, nor is the exstata. But you guys who managed to grab boards are a lucky lot. Lots of enjoyment to fill these forums shortly i suspect.

 

[HeadphoneAddict]

Quote:

I think I am now very very interested to do a direct comparison with an O2MK1 + Exstata versus a nice LCD-2 system. Had a chance to listen to an exstata i built for a friend months ago with the O2Mk1 today and I was blown away. While the Wharfie zebs edge out the O2 in some very specific areas the stat system around the O2 annhilates the wharfie zebrawoods + Liquid gold setup. The effect is similar to the LCD-2 for me. 
 
Wish I could spend some serious time with an O2 + Exstata system. Sadly the O2 wasn't mine, nor is the exstata. But you guys who managed to grab boards are a lucky lot. Lots of enjoyment to fill these forums shortly i suspect.

If you really think you would use an eXStatA for yourself, I have a set of Hybrid boards that I could pass on to you so you could build your own amp.  This offer is for you only, so I don't want PM from other people about them right now. I did offer them to Paxeaxe but he found another set.  Otherwise I planned to build a hybrid amp for myself someday, since I'm giving the completed hybrid to my son.

 

[BoilermakerFan]

I also have two SS boards sets, matched quads of the J271s, and PS iron kits still available.  Posting here, then they'll posted in the FS forum next week. 
 

 

[HeadphoneAddict]

Quote:

If you really think you would use an eXStatA for yourself, I have a set of Hybrid boards that I could pass on to you so you could build your own amp.  This offer is for you only, so I don't want PM from other people about them right now. I did offer them to Paxeaxe but he found another set.  Otherwise I planned to build a hybrid amp for myself someday, since I'm giving the completed hybrid to my son.

Quote:

I also have two SS boards sets, matched quads of the J271s, and PS iron kits still available.  Posting here, then they'll posted in the FS forum next week. 
 

It looks like Sachu wants to take my hybrid set.  If he does, I would like to buy one of your "SS set with J271's and PS iron kits".  I'll know by this afternoon.

 

[BoilermakerFan]

Quote:

It looks like Sachu wants to take my hybrid set.  If he does, I would like to buy one of your "SS set with J271's and PS iron kits".  I'll know by this afternoon.

Works for me Larry.  Saachi emailed me, but we can take it to PMs as you have two options on the iron I need to help you with.  I'll pass the boards on to you at the GB cost and the iron at cost too.  Marc just mailed the J271s so they'll be here early next week.