Nobsound Tube Pre-Amp+Crown XLS-1500 Digital Amp

Of the three 12ax7 Tubes: Is the middle one a buffer? The outer two Right and Left channels?

As long as it functions properly the rectifier tube has no real affect on the sound. Can't say for sure if the middle tube is a buffer. You could try an odd one there and a matched pair on the outside. Although as I said before that thin board has too much flex which discourages tube rolling.

:thmbsp:

See attached...
 

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Here's an "article" that gets into details of the XLS amps. Page two has some techno jargon that you may be able to make heads or tails out of regarding the a/d>d/a conversions.

http://www.prosoundweb.com/article/designer_notebook_inside_new_crown_xls_series_power_amplifiers/

Still not really clear, but I think it supports the amp having a/d > d/a conversion.

To me it reads like:

Signal input 》A/D conversion 》DSP 》D/A conversion 》PWM control 》switching output stage 》reconstruction filters 》speaker output

Lest anyone think I mean this to be derogatory, no way. I'm not a purist in this regard (analog vs digital stages). If the amp sounds good it sounds good regardless how it does what it does.
 
Frank Sol, where does that schematic come from? Is there any way to get a clearer version, and/or one with voltages?
 
Although as I said before that thin board has too much flex which discourages tube rolling.


Yeah... I'm going to put in some tubes the first time around and hopefully leave them be

I do not have a tube tester but I had my 12AX7 tubes tested today, these tested as a strong 'Good':

Electro-Harmonix 12AX7-EH Gold
Genalex Gold Lion ECC83/B759 (Premium)
Mullard 12AX7 / ECC83 (Russian)
Baldwin Green (Sylvania) 12AX7

Thinking about putting the Gold Lions on the outside and a single Mullard in the middle
 
SURPRISE !!

It showed-up today...

I swear I could not put in the Gold Lions or Mullard. I began to sweat while trying. The Chinese 6Z4 went it easily.

So, I put some Deoxit on a Q-Tip then swabbed the pins on the Chinese 12ax7 and slowly wiggled them in. Even they were a little hard getting in. Tested the preamp -- A-OK :thmbsp:

After about an hour of playing I shut it down and let it cool off a bit.

Then I began to purposely wiggle the Chinese 12ax7 out very slowly. Hoping to widen the socket. Swabbed the Gold Lions and Mullard pins with deoxit then they went in :banana:

New tubes been playing about 45 mins
 

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This will not be a surprise... the better tubes make this little preamp transform into a butterfly. Those Chinese 12ax7 are crap

Three hours in: I'm impressed

Will move the Nobsound into the main system in about 2 hrs
 
Frank, I'm glad you like it.

It's hard to find a decent tube preamp at twice the price of the Nobsound.

Don't know if you have a tube pin straightener but after using one it made it easier to rock my Telefunkens back and forth till they seated in the sockets.
 
Got mine on ebay

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Nice! I can hardly wait for my TPA3116 :banana:

Does this T-Amp begin back memories ?


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Sweet. If not for the trail blazing Sonic Impact we might not have the TPA3116 :thmbsp:

That linear regulated power supply should be a match made in heaven with the TPA.
 
This Sonic Impact is a much better mate to the Nobsound than a Crown XLS1500 or my Krell KSA150

Believe it or not ;) my Behringer A500 sounds the best so far but I need more time with this T-Amp
 
This Sonic Impact is a much better mate to the Nobsound than a Crown XLS1500 or my Krell KSA150

Believe it or not ;) my Behringer A500 sounds the best so far but I need more time with this T-Amp

So TPA-3116 or the Sonic Impact amp with the Nobsound?
Just when I thought I would be getting the Crown XLS-2000 tp pair with it. :)
 
So TPA-3116 or the Sonic Impact amp with the Nobsound?


Just when I thought I would be getting the Crown XLS-2000 tp pair with it. :)


I do not have the double chip TPA-3116 yet... Maybe arriving tomorrow

I was splitting hairs in my comparison :yes: All would depend on personal taste and/or speakers

The Nobsound & Crown pair did not sound bad! They were very detailed not 'lush' sounding. Lush can be a good thing with horns

BTW-- My Behringer A500 amazes me sometimes... Sounds way better than it should unless it is pushed too loud
 
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