TX102 and DAC turbo (Off Topic)
by soundcheck 
, Germany, Thursday, August 31, 2006, 14:19 (6441 days ago)
Hi all.
Since I know that quite some guys here using battery powered DACs
and S&B TX102 I'd like to share two major tweaks I figured/tried out
during the last weeks.
For me these are a must and never ever without it tweaks!
1.
I just installed one Northstar 90NSB battery with an ESR of <0,003R to power my DAC and another one to power my Tripath 2020 based AMP.
(I know - Some guys would call it overkill - but keep reading below.)
It took me awhile to figure out what battery would suit best.
A car mechanic firing his 2000W rig with Northstar gave me that hint and
the convincing explanation. I thought by myself. What's good for a 2000W
Amp must be very good for a 20W Amp and DAC.
Before I was running a 25Ah and 10Ah Exide/Sonnenschein Dryfit A512.
The Sonnenscheins in general are rated to be the better ones.
And yes I agree. The sound was decent. Lets say I was not unhappy.
The Northstar battery can deliver short ciruit current of 4500A!!
and weighs 27kg. ( Be careful not to cause a short circuit!):wink:
I just can say. Battery and Battery. It makes a real big difference.
It'll blow you off. Its 180€ a piece if you're lucky.
I can understand now what the SMPS lovers were trying to tell me, when they
were saying batteries do not deliver the "Punch" or I would call it dynamics.
But these batteries, a little buffered and filtered, do. And they do it better, much better!
Give it a try! Its worth it.
2.
One more:
Run your TX102 in Autotransformer Mode.
( I am wondering if that has been discussed here already)
It gives you more dynamics and resultion. That's what usually is critisised
about the TX102.
If you run the TX unbalanced try this. Just´connect your ++ lead of the
input to the 0db lead of the output. And listen! That's a ten minutes
0€/$ tweak. You'll love it. If you make it permanent you should take the
0db lead off the switch.
You'll find more Infos on DIY-Audio com. Just search for it.
But it is as easy as described above. Nothing more about it.
Bert isn't that something for your next audio gathering!
Feedback and other experiences on the subject are always welcome.
Klaus
DAC turbo
Hi Klaus,
I noted a good improvement in dynamics and quietness upgrading from 7Ah to 24Ah powering my DDDAC1543. Now you tell me there is much more.
But these batteries, a little buffered and filtered, do.
What buffering and filtering arrangement do you use?
Best regards
Steve
DAC turbo
by soundcheck , Germany, Thursday, August 31, 2006, 17:40 (6441 days ago) @ goon-heaven
Hi Steve.
Its all about the batteries ESR. I'd guess that your battery still
has 20-30mR ESR.
Unfortunately it seems that one needs a real big battery to get that far
down. But I figured that every mR counts on the supply rail.
Without switch and connector it was perfect. The pity is - there is no way
around these you have to have them in! It is just do dangerous without switch and connector.
I am buffering with 8*470uF + 0,2uf (BG NONpolars) and a 1000pF ceramic (0805 Type with silver leads - DIY).
Klaus
Hi Klaus,
I noted a good improvement in dynamics and quietness upgrading from 7Ah to
24Ah powering my DDDAC1543. Now you tell me there is much more.
But these batteries, a little buffered and filtered, do.
What buffering and filtering arrangement do you use?
Best regards
Steve
DAC turbo
Hi Klaus,
Its all about the batteries ESR. I'd guess that your battery still
has 20-30mR ESR.
No idea of its ESR. It has a specified internal resistance of 9mR, but that will be DC, I guess.
Unfortunately it seems that one needs a real big battery to get that far
down. But I figured that every mR counts on the supply rail.
Without switch and connector it was perfect. The pity is - there is no
way
around these you have to have them in! It is just do dangerous without
switch and connector.
Yes, I see the difficulty. So what difference in ESR does adding your best switch and connector make?
I am buffering with 8*470uF + 0,2uf (BG NONpolars) and a 1000pF ceramic
(0805 Type with silver leads - DIY).
Thanks. I guess I have some room for improvement here too.
Best regards
Steve
DAC turbo
by soundcheck , Germany, Tuesday, September 05, 2006, 10:12 (6436 days ago) @ goon-heaven
Hi Steve.
I have a "One piece silver contact" 15A type of switch. Which counts for 0,003R.
And connectors are Neutrik Speakon < then 0,002R per leg. Makes 4 legs.
So it should be less then 0,008R two ways for the connector.
Gives you a total of approx. 0,01R. Fair enough. I could not find
any lower values. Some people were recommending Power-Fets as switches.
I was afraid that they introduce more noise to the whole circuit. I left them out.
I do not have the system fuse proteced! That's a NoGo for me. Good to be DIYer.
I gotta trust my own work. Though I installed a fire protector above the system. You never know. 
Klaus.
All connector contacts are of course cleaned and treated with Walker Audio
Extreme SST! To improve the contact resistance even further.
Klaus
Hi Klaus,s
Its all about the batteries ESR. I'd guess that your battery still
has 20-30mR ESR.
No idea of its ESR. It has a specified internal resistance of 9mR, but
that will be DC, I guess.
Unfortunately it seems that one needs a real big battery to get that
far
down. But I figured that every mR counts on the supply rail.
Without switch and connector it was perfect. The pity is - there is no
way
around these you have to have them in! It is just do dangerous without
switch and connector.
Yes, I see the difficulty. So what difference in ESR does adding your best
switch and connector make?
I am buffering with 8*470uF + 0,2uf (BG NONpolars) and a 1000pF ceramic
(0805 Type with silver leads - DIY).
Thanks. I guess I have some room for improvement here too.
Best regards
Steve
TX102 and DAC turbo
by Bert , Saturday, September 02, 2006, 11:53 (6439 days ago) @ soundcheck
Hi Klaus,
Run your TX102 in Autotransformer Mode.
Bert isn't that something for your next audio gathering!
Thanks for the tip, I will do that tweak when I have my system back home and report back.
I tried to demo my system at a local audiophile club. Again I was the guiny pick to demo at their new location which I never want to be again!
The sound was not comparable to what I was used to hear, weird echo reflections and strong background noise seemed to be the major problem. I even thought that there was something completely wrong with the system, highly de-motivating!
The next day I brought the same system to a friend's place (not that much work because everything was already packed and loaded in my car).
Thank God that there is nothing wrong with the system, in Peter's room the Swing's are playing the stars from heaven! It was needed to replace his pre-amplifier for the Django to clean up the sound though. Even with his 400W SS power amps connected, there is not much to complain, we just enjoyed listening the music until late in the evening!
Thanks Peter for the oppertunity, things are okay again for me... :drinks:
Bert
--
BD-Design - Only the Best!
TX102 tweak..
by Bert , Wednesday, September 06, 2006, 15:01 (6435 days ago) @ soundcheck
Hi Klaus,
I have done some little search at diy.com but I can't find anything related so quickly.
I did connect the ++ of the transformers (same connections as the inputs so that one was easy to find for primarely testing) to the 0 output wires which I disconnected form the attenuator switch (last selection does not give sound now).
Without using the +6dB position nothing changed (I have not listened yet except for errors) but when switching to the +6dB setting the output level is highly reduced, like almost shortcutting the input.
What am I doing wrong here?
Ciao,
Bert
--
BD-Design - Only the Best!
TX102 tweak..
by soundcheck , Germany, Wednesday, September 06, 2006, 16:36 (6435 days ago) @ Bert
Hi Bert.
I do not have the +6db option connected.
My input looks as it's supposed to be for a standard RCA connection:
++ hot (goes to 0db output lead)
-- connected to +
- cold (is connected to all other ground/shield leads)
Klaus
TX102 tweak..
by Bert , Wednesday, September 06, 2006, 17:42 (6435 days ago) @ soundcheck
Hi Klaus,
I do not have the +6db option connected.
Okay...
My input looks as it's supposed to be for a standard RCA connection:
++ hot (goes to 0db output lead)
-- connected to +
- cold (is connected to all other ground/shield leads)
So, you have the primary windings in series (+6dB as standard)?
Why should I remove the 0 lead from the attenuator switch? This means that I do not have any output when done at that setting. Sometimes I do use that setting though... 
Ciao,
Bert
--
BD-Design - Only the Best!
TX102 tweak..
by soundcheck , Germany, Thursday, September 07, 2006, 18:02 (6434 days ago) @ Bert
Hi Bert.
Why should I remove the 0 lead from the attenuator switch? This means that
I do not have any output when done at that setting. Sometimes I do use that
setting though...
You're challenging me. :wink:
I was trying hard to find the thread at DIY-Audio, which explained it. Without success!
In the end I tried to figure it out by myself.
Here is my expalanation:
Autotransformer:
Basic principle/characterisitics: One winding. An extra tap is used as output. Galvanic separation is lost. But all windings are used. It's more a less a terminated transformer. (I wonder if that makes sense.)
Now my explanation: The only thing I see by looking at it. You'd short-circuit the primary!
Because the Input Voltage would be at the same size as the Output Voltage
on the 0db tap but the induced output Voltage would have the opposiste direction.
So the sum would be 0. Which is the basic roule of a transformer that
all Voltages and induced voltages sum up to 0.
That looks to me like a short circuit on the primary.
Does anybody have a better idea?
Klaus
Hi Klaus,
I do not have the +6db option connected.
Okay...
My input looks as it's supposed to be for a standard RCA connection:
++ hot (goes to 0db output lead)
-- connected to +
- cold (is connected to all other ground/shield leads)
So, you have the primary windings in series (+6dB as standard)?Why should I remove the 0 lead from the attenuator switch? This means that
I do not have any output when done at that setting. Sometimes I do use that
setting though...Ciao,
Bert
Correction... :)
by Bert , Wednesday, September 06, 2006, 17:45 (6435 days ago) @ soundcheck
Hi again,
You have standard the windings in series which means 0dB instead of +6dB as I mentioned before...
It was a bit late last night...
Ciao,
Bert
--
BD-Design - Only the Best!
Correction... :)
by soundcheck , Germany, Monday, September 11, 2006, 22:09 (6430 days ago) @ Bert
Hi Bert.
Any news on this one. Did you have a chance to give it a listen?
\Klaus
Hi again,
You have standard the windings in series which means 0dB instead of +6dB
as I mentioned before...It was a bit late last night...
Ciao,
Bert
Correction... :)
by Bert , Monday, September 11, 2006, 22:47 (6430 days ago) @ soundcheck
Hi Klaus,
Any news on this one. Did you have a chance to give it a listen?
I still have the wires hanging loose from the stepped attenuator and was waiting for your answer to that...
Should I have these disconnected?
BTW, not much time to listen to tweaks, I am working too hard on more important things... customers do not like to wait! And things do not go smoothly... :sad:
ciao,
Bert
--
BD-Design - Only the Best!
Correction... :)
by soundcheck , Germany, Tuesday, September 12, 2006, 08:35 (6429 days ago) @ Bert
Hi Bert.
See my answer from the 7th! It should explain what's happening.
\Klaus
Hi Klaus,
Any news on this one. Did you have a chance to give it a listen?
I still have the wires hanging loose from the stepped attenuator and was
waiting for your answer to that...Should I have these disconnected?
BTW, not much time to listen to tweaks, I am working too hard on more
important things... customers do not like to wait! And things do not go
smoothly... :sad:ciao,
Bert
Correction... :)
by Bert , Tuesday, September 12, 2006, 09:46 (6429 days ago) @ soundcheck
Hi Klaus,
See my answer from the 7th! It should explain what's happening.
It doesn't explain it to me... 
I know that I made the mistake to shortcut the windings by using the +6dB switch which is also in the circuit, I should change that wiring if I want to use the +6dB option.
Here is your original posting:
If you run the TX unbalanced try this. Just´connect your ++ lead of the input to the 0db lead of the output. And listen! That's a ten minutes 0€/$ tweak. You'll love it. If you make it permanent you should take the 0db lead off the switch.
The last sentence is still bothering me. Which switch are you talking about?
The only switch where I have the 0 leads connected to is the stepped attunuator switch and when disconnecting these (L + R) then there is no sound coming from my Django at the last setting (normally this setting connects the 0 lead to the output for "full power").
Ciao,
Bert
--
BD-Design - Only the Best!
Correction... :)
by soundcheck , Germany, Tuesday, September 12, 2006, 10:40 (6429 days ago) @ Bert
Lets see.
Shurtcutting the primary, by having the 0db tap and the output tap and
the ++ tap at the same point, where the output voltage has 180degree phase difference compared to the input voltage. This leads to a 0 Volt potential on the ++ tap. To me that looks like a short circuit on the primary.
Perhaps I should prepare a drawing.
I can't help on the 6db setup. I do not have it installed.
Klaus
Hi Klaus,
See my answer from the 7th! It should explain what's happening.
It doesn't explain it to me...I know that I made the mistake to shortcut the windings by using the +6dB
switch which is also in the circuit, I should change that wiring if I want
to use the +6dB option.Here is your original posting:
If you run the TX unbalanced try this. Just´connect your ++ lead of the
input to the 0db lead of the output. And listen! That's a ten minutes 0€/$
tweak. You'll love it. If you make it permanent you should take the 0db
lead off the switch.The last sentence is still bothering me. Which switch are you talking
about?The only switch where I have the 0 leads connected to is the stepped
attunuator switch and when disconnecting these (L + R) then there is no
sound coming from my Django at the last setting (normally this setting
connects the 0 lead to the output for "full power").Ciao,
Bert