[ZenTriode]

Hi guys,
 
What I meant by "externally" was to place the resistor in a headphone extension cable.  This could be done separate from the Taboo MK III. 
 
By purchasing an XLR jack that is male, and a second XLR jack that is female it would be possible to wire a resistor between the two jacks and experiment with different values.  Once you find the value you want, you can order that value from mouser using the part number I supplied for best sound quality. 
 
As for internally modifying your units, I don't have a problem working with small repair shops via email to guide them in what to do, but I am reluctant to post what to do on this public forum.  There are dangerous voltages inside not to mention working on it yourself could void the warranty.
 
It should also be noted that this is not a fix, it is a mod.  You can't fix what's not broken, and for those hearing hum on non LCD2 headphones, this mod would likely help a great deal.
 
 

Thanks,
 
Steve

 

[ZenTriode]

I should also mention that if you create an extension cable for the XLR jacks that employes a 150 ~ 1000 ohm resistor, the output of the single ended headphone jacks will remain unaffected.   On the same note, creating an extension cable for the single ended headphone jack would have no effect on the XLR outputs.
 
Thanks,
 
Steve

 

[jeust0999]

I just placed an order for a taboo. Really looking forward to my first tube amp!

 

[longbowbbs]

  I just placed an order for a taboo. Really looking forward to my first tube amp!

 
You will love it!

 

[Pentode Guy]

Dan,
There's a recent case over at Decware forum where a unit was having hum on one channel. It turned out he had "incorrect layout" as per warranty repair invoice.

 

[Lord Soth]

Dan,
There's a recent case over at Decware forum where a unit was having hum on one channel. It turned out he had "incorrect layout" as per warranty repair invoice.

 
For all cases of hum, it is best to contact Steve Deckert (Decware) directly.
 
The situation might not be identical.
 
The unit in question was a CSP3 rather than a Taboo.
 
The affected owner contacted me privately for advice on his hum issue.
He then updated me on the repair details.
It turned out that his CSP3 could not accept any tubes on the right output other than the default 6N1P stock tubes.
After changing the layout under repair, his unit can now accept other tubes (e.g. E288CC) without any hum.

 

[WNBC]

Wow!  I was racking my brain trying to figure out why only the stock tubes resulted in no hum in the CSP3!  I bought 3 new Gold Lion 6922s because I thought maybe my old tubes were just too noisy for the transparency of the CSP3.  All 3 hummed loudly and I was thinking what was the chance that all 3 were bad.  I am going to double check tonight one last time that I can't use anything but the stock tubes, but I'm pretty sure.  
 
Lord Soth, you are the man!
 
 
Quote:

 
For all cases of hum, it is best to contact Steve Deckert (Decware) directly.
 
The situation might not be identical.
 
The unit in question was a CSP3 rather than a Taboo.
 
The affected owner contacted me privately for advice on his hum issue.
He then updated me on the repair details.
It turned out that his CSP3 could not accept any tubes on the right output other than the default 6N1P stock tubes.
After changing the layout under repair, his unit can now accept other tubes (e.g. E288CC) without any hum.

 

[funch]

That's interesting. My CSP2+ also had humming/buzzing in the right channel. It actually killed a 6DJ8 tube in about 30 minutes. I've since given
up on using 6922 variants in the output and am now using a pair of triple-mica 6N1P's which sound great.
 
I'm curious what the 'incorrect layout' actually is.

 

[Argo Duck]

Same here with my (previously CanDude's) CSP2+ :eek: It has to have 6N1P tubes in the output positions. May only be one channel, but didn't really take note.

As I was completely able to tailor the sound with the driver and rectifier tubes - and it runs silent with these and 6N1P output tubes - I got on with listening and forgot about the problem. Hmm...

 

[Lord Soth]

Dear WNBC, funch and AiDee

On my CSP2+ and CSP3, I confirm that I can use all manner of tubes in the 6DJ8 family without any hum.
I have tube rolled without any mishaps, even with rectifiers.

The logical conclusion I can draw from this is that maybe there is one particular amp builder in Decware who's been making this layout mistake.
Otherwise everyone's amp would have the same problem.

 

[WNBC]

AiDee, same here.  The 6N1P sound great in the CSP3 and I thought I might tackle the problem with other tube variants later on.  Everything makes sense now.  When I first tried the CSP with my non-stock tubes I heard a hum issue but figured my 6DJ8 and 6922 tubes were fine for say my old Lyr but not up to snuff for the CSP.  I put in the stock tubes and no problem.  Two weeks ago I bought some Gold Lion 6922s and had the hum issue.  
 
Lord Soth,   
Agreed, most people can tube roll without an issue.  I have an early production CSP3.  
 
 
Thanks guys, now I'm relieved.  My CSP3 problems are fixable!  And I could always stick with the 6N1P tubes but I was born to roll.
 
 
Quote:

Same here with my (previously CanDude's) CSP2+

It has to have 6N1P tubes in the output positions. May only be one channel, but didn't really take note.

As I was completely able to tailor the sound with the driver and rectifier tubes - and it runs silent with these and 6N1P output tubes - I got on with listening and forgot about the problem. Hmm...

 
 

Dear WNBC, funch and AiDee

On my CSP2+ and CSP3, I confirm that I can use all manner of tubes in the 6DJ8 family without any hum.
I have tube rolled without any mishaps, even with rectifiers.

The logical conclusion I can draw from this is that maybe there is one particular amp builder in Decware who's been making this layout mistake.
Otherwise everyone's amp would have the same problem.

 

[Argo Duck]

Thanks LS & WNBC

CanDude's CSP2 got checked out and re-certified on its way to me some 17 months ago. I imagine the layout issue hadn't been identified at that time.

I'm probably happy with my unit (the Taboo is my main amp) but if I ever on-sell I will draw Decware's attention to the possibility this happened with my unit, for them to fix if necessary during re-certification.

 

[clowkoy]

There is another reason why 6N1P's are quiet in the CSP. As you know, the filaments in the CSP are DC-heated through a simple CRC. Without load, the DC voltage reaches >7 volts. The 6N1P tubes draw around 650-700ma each, that's twice the current draw of 6922/6DJ8/6N23P. With 3-6N1P tubes in the CSP, the voltage would drop to 4.30 volts, that's running tubes at 70% of the required 6.3 volts. This was confirmed by another CSP owner over at Decware forum. I guess this is what Steve called "starved filament technology", probably a patented technology since I don't know of any other tube amp manufacturer going this low of a filament voltage. Now, if you use the regular 6922/6DJ8 tubes, the voltage would go up to 5.7-6.0 volts since they're only drawing half the amount of current, well within the 10% variation allowed by tube manufacturers.

 

[thegrobe]

Oh Boy! Look what came today after a long search! Three NOS 596's, all from the same week in 1957. Two are a tightly matched pair. Also some adapters from 2359glenn today too!..What timing! 
 
Fun with tubes 

 

 

[longbowbbs]

  Oh Boy! Look what came today after a long search! Three NOS 596's, all from the same week in 1957. Two are a tightly matched pair. Also some adapters from 2359glenn today too!..What timing! 
 
Fun with tubes 

 

Nice looking bunch of 596's! I do love that tube with Decware!