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The best sounding I/V resistor

Posted 3rd March 2013 at 10:22 AM by dvb projekt
Updated 30th November 2016 at 09:17 AM by dvb projekt

As many of you know, i am using the Texas Components TX2575 Bulk Z-Foil resistor for a long time
in important circuit positions, especially as I/V resistor.

Recently i stumbled over a short recommendation from Thorsten Loesch.

Quote:

Originally Posted by ThorstenL

Hi,
I would second Rohpoint, Neohm less. Rohpoint are truely excellent. For my first TDA1541 Non-OS DAC (in 98) I handmade bifilar wound Non-inductive 25 Ohm resistors.
In susequent builds I compared to Rohpoint (which I have used extensively and found no reason to handwind resistors.

In my commercial designs we use a specfic type of SMD resistors after auditioning tons.
Some SMD resistors are really bad, some are so-so and some are most excellent, though no patch for a Rohpoint Squaristor GR102.

Ciao T

Because i know Thorsten as a man who had the perfect sound in mind,
i ordered one pair 30R to try them in my Tube-I-zator.

Please note: ROHS compliant parts are now green and the second letter in the part number is 'G'.

Thorsten´s post make me very curious. Could this resistor beat the TX2575 in the I/V position?

After one hour of warm up i start listening.
The first few notes from Patricia Barber´s "Companion" XRCD came through my Duo Omega horns and...

...WOW...

I haven´t heard so many coloration from each instrument and voices before.
Also the stage is more 3 dimensional as before and this without loosing the perfect and well known speed and clarity of the TX2575.

However, the Rhopoint Squaristor GG102A is not cheap, but it´s sound quality as I/V resistor is phenomenal.

I am glad that i had try it and could totally second Thorsten´s opinion.

Highly Recommended

Posted in Project builds, Reference TDA1541A DAC

Views 8167 Comments 16

« The Red Baron DAC Module V4.0 - Out of production Main Tube-I-zator V2.0 / TDA1541A recommended modification »

Total Comments 16

Comments

	Thanks for the tip!
	Posted 12th March 2013 at 03:26 PM by Bas Horneman

	Now that you've found the perfect resistor. Don't you think you should solder them in directly into your board"? Since now it is pcb->solder->brass pin or nickel over copper->resistor. Then you would have pcb->solder->resistor
	Posted 12th March 2013 at 03:29 PM by Bas Horneman

	Quote: Originally Posted by Bas Horneman Now that you've found the perfect resistor. Don't you think you should solder them in directly into your board"? Since now it is pcb->solder->brass pin or nickel over copper->resistor. Then you would have pcb->solder->resistor It has a specific reason, why they are still in the pin´s! Wait and see...
	Posted 18th March 2013 at 05:58 AM by dvb projekt

	Ok. Standing by for news!
	Posted 27th March 2013 at 03:21 PM by Bas Horneman

	It has been 4 months, did you do what you were talking about with the soldering or is it the new Tube-I-Zator 3? Thanks Do
	Posted 13th July 2013 at 01:40 AM by pinnocchio

	Quote: Originally Posted by pinnocchio It has been 4 months, did you do what you were talking about with the soldering or is it the new Tube-I-Zator 3? Thanks Do It was the new Tube-I-zator V3.0, correct!
	Posted 13th July 2013 at 05:26 AM by dvb projekt

	Optimal value of I/V resistor Oliver What do you now consider the optimal value of this resistor for I/V in tubizator with one tda and 6np2 tubes. I was thinking 56-68 ohm but want to get this right before ordering $$ parts. Walter
	Posted 16th July 2013 at 02:33 AM by wlowes

	Optimal value of I/V resistor Quote: Originally Posted by wlowes Oliver What do you now consider the optimal value of this resistor for I/V in tubizator with one tda and 6np2 tubes. I was thinking 56-68 ohm but want to get this right before ordering $$ parts. Walter Hi Walter, i would recommend 56R. Get the closest value they offer. Cheers, Oliver
	Posted 16th July 2013 at 06:04 AM by dvb projekt

	Thanks for the i/v value tip. One more question... I see you use T2575 in the RK position. I know the I/V is critical. Did you see much impact using T2575 here? I have been using Kiwame and will be moving to NOS shintok Tantalum with Red Baron. Did not know if this spot warrants the $$.
	Posted 3rd August 2013 at 01:34 PM by wlowes

For anyone doubting the value of resistor in I/V I can add one more to the many posts. I am working my way thru comparisons. Started with Takman 72R metal film. Can't knock it. Very good sound. Very precise and lots of air. Swapped in Amtrans 53R. Immediately you could tell there was new detail but initially the life was gone. Sounded again mechanical and digital. I let them burn in 10 hrs. Then they sounded promising. Less mechanical and fairly sweet. Much more detail but still some kind of veil... no air. After 50 hrs they were coming into life and sounding very good. Great detail, wide 3d sound stage. At 100 hrs I could love this sound if I did not miss the dark silence and air.
So in went Caddock TF020 50R immediate improvement with no burn in. I look forward to seeing where we are with 100 hrs.
I can understand now why these VERY expensive Rohpoint could be worth it. I have ordered manganin wire to make my own using non inductive winding. It will be a while before I get there but thank you Oliver for encouraging us to take these steps. Well worth the expense and the effort!!

Posted 4th August 2013 at 01:28 AM by wlowes wlowes is offline

Quote:

Originally Posted by wlowes

Thanks for the i/v value tip.

One more question... I see you use T2575 in the RK position. I know the I/V is critical. Did you see much impact using T2575 here? I have been using Kiwame and will be moving to NOS shintok Tantalum with Red Baron. Did not know if this spot warrants the $$.

I didn´t make any comparisons for the Rk position. What i had in mind is to use the resistor with lowest noise.

If you would like to compare, it would be great if you share your findings.

Best regards,
Oliver

Posted 5th August 2013 at 10:49 AM by dvb projekt dvb projekt is offline

	Hi where can I buy thoose Rhopoint resistors ? Thank You
	Posted 30th October 2013 at 09:59 PM by Erlend Sæterdal

	Quote: Originally Posted by Erlend Sæterdal Hi where can I buy thoose Rhopoint resistors ? Thank You You could order them direct at Rhopoint.
	Posted 31st October 2013 at 06:07 AM by dvb projekt

I´ve heard about I/V resistor so many times. Why not try this?
Find out, which is the lowest R possible at the DAC output, then take the minimum value as a fix resistor and a trim in series and listen, where it sounds best. There are fantastic trims out there, now. I´ve tried that at another place. But be aware about the solder direction of both! The trims are 1202 from Texas components... if you found the sweet spot, you can take a fix value again or the combination...depending on what you like best (and I cannot predict the result)

Posted 13th April 2015 at 03:09 PM by Scheff Scheff is offline

	How much do they cost?
	Posted 22nd April 2015 at 01:49 PM by taccodude

	Hey, thanks for the tip. The GG102A is truly amazing. Better than the previous S102K resistor. While the sound from S102K is already airy and clear, but the GG102A adds more depth (3D) and fluid. It's hard to believe a wirewound resistor will have such enhancement.
	Posted 8th October 2016 at 02:59 AM by canvas

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The best sounding I/V resistor

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Optimal value of I/V resistor

Optimal value of I/V resistor