[mimaximax]

What is a low NFB design? And what about the longevity of tube preamps?

 

[KaiSc]

What is a low NFB design?

NFB is a common abbreviation for Negative Feed Back, used in amplifiers:

With NFB an amp compares output with input, generates a correction signal that counteracts distortions and load depended signal changes.

NFB has a huge influence on the sound of an amp.
Low order distortions in the mid- and hi-power range are reduced the most by NFB.
This is not always desirable, as the way distortions build up with increasing power contribute a lot to the character of an amp.

Audiophile tube amplifiers often use low amounts of NFB only, to achieve a soft, gradual built-up of 2nd and 3rd order distortions with increasing loudness.

Non-Linear-Distortions (as is the precise term) or the “right” kind are like spice to the music.
Well-dosed they can add a nice flavor, too much can spoil the result.

 

[jlbrach]

Wait, what? Seriously?! Now I'm embarrassed. I own a CFA3 and had no idea. But if I am going to be embarrassed, I'm glad it's with great news. Excited to try this out . . .

I have the cfa3 as well with both the sr1a and the ca-1a and I would be very concerned about connecting them without the adapter but if others try it and say it works I will think about it

 

[normie610]

I have the cfa3 as well with both the sr1a and the ca-1a and I would be very concerned about connecting them without the adapter but if others try it and say it works I will think about it

It works but doesn’t sound good. You can try for the sake of trying, but definitely not the way to go.

 

[jlbrach]

ok, then I will stick with the adapter box

 

[Litlgi74]

I've tried the standard interface box (RI-1a) with the CFA3 and have had no problems doing so... but... Might the new TI-1a be the better solution for the low powered (vs speaker amp) CFA3?

 

[Aleksandar R.]

I've tried the standard interface box (RI-1a) with the CFA3 and have had no problems doing so... but... Might the new TI-1a be the better solution for the low powered (vs speaker amp) CFA3?

That's the idea behind the TI vs RI!
With TI, there will be about 6-7dB more of max SPL on headphones. And the current draw from the amp will be far lower for the same SPL.

However, to get that, you can't use the old "standard" cable that was coming with the RI.
That's why now the headphone cable belongs with the TI set, not with the headphones. We need to correctly load those transformers to get the expected result, as well as 32/16 Ohms at their input.

 

[normie610]

That's the idea behind the TI vs RI!
With TI, there will be about 6-7dB more of max SPL on headphones. And the current draw from the amp will be far lower for the same SPL.

However, to get that, you can't use the old "standard" cable that was coming with the RI.
That's why now the headphone cable belongs with the TI set, not with the headphones. We need to correctly load those transformers to get the expected result, as well as 32/16 Ohms at their input.

On the subject of cables, how far are you from offering the upgraded cables? I remember you mentioned in one of the posts that you are preparing to launch some new headphone cables for the TI box.

 

[Aleksandar R.]

On the subject of cables, how far are you from offering the upgraded cables? I remember you mentioned in one of the posts that you are preparing to launch some new headphone cables for the TI box.

I'm happy to say that we are done with testing and trials, and couldn't be happier with the result!
Figured out the annealing cycles, got the braided jackets designed and made, just waiting for the printed sleeves, then make some and ship them to Danny!
He will have a few delivered on Monday the 26th. Sep.

BTW, Danny had a pair of production prototypes playing at CanJam. They looked like this, but with printed markings:

The specs of Star-8 Pure Silver are:

6ft in length
~0.23 Ohms (loop resistance), same like SC2, so no extra power needed in comparison.
~0.37uH at 6ft.

We got increased resolution, but without harshness, with increased bandwidth of the TI-cable-headphones chain.

I have to say that Danny and I have never heard the SR1, CA1 and TI sounding like this before. There is so much happening in the music, but without imposing itself on you. We are enjoying the discovery that our headphones are much better than we thought

 

[normie610]

I'm happy to say that we are done with testing and trials, and couldn't be happier with the result!
Figured out the annealing cycles, got the braided jackets designed and made, just waiting for the printed sleeves, then make some and ship them to Danny!
He will have a few delivered on Monday the 26th. Sep.

BTW, Danny had a pair of production prototypes playing at CanJam. They looked like this, but with printed markings:


The specs of Star-8 Pure Silver are:

6ft in length
~0.23 Ohms (loop resistance), same like SC2, so no extra power needed in comparison.
~0.37uH at 6ft.

We got increased resolution, but without harshness, with increased bandwidth of the TI-cable-headphones chain.

I have to say that Danny and I have never heard the SR1, CA1 and TI sounding like this before. There is so much happening in the music, but without imposing itself on you. We are enjoying the discovery that our headphones are much better than we thought

Sounds like a winner! Will there be other cables planned in the pipeline or Star-8 is the only one?

 

[jlbrach]

I'm happy to say that we are done with testing and trials, and couldn't be happier with the result!
Figured out the annealing cycles, got the braided jackets designed and made, just waiting for the printed sleeves, then make some and ship them to Danny!
He will have a few delivered on Monday the 26th. Sep.

BTW, Danny had a pair of production prototypes playing at CanJam. They looked like this, but with printed markings:


The specs of Star-8 Pure Silver are:

6ft in length
~0.23 Ohms (loop resistance), same like SC2, so no extra power needed in comparison.
~0.37uH at 6ft.

We got increased resolution, but without harshness, with increased bandwidth of the TI-cable-headphones chain.

I have to say that Danny and I have never heard the SR1, CA1 and TI sounding like this before. There is so much happening in the music, but without imposing itself on you. We are enjoying the discovery that our headphones are much better than we thought

so can I assume this cable will provide the juice needed to drive through the TL box because some do not

 

[Aleksandar R.]

Sounds like a winner! Will there be other cables planned in the pipeline or Star-8 is the only one?

Well, we are somewhat biased, naturally, but it's really a winner. We've learned along the years how to remove the bias as much as possible.

The plan is to try to do the same cable topology in Copper and adapt it for interconnects and input cable for TI.
We shall be quick about it and get those out soon (if they pass the scrutiny).

 

[Aleksandar R.]

so can I assume this cable will provide the juice needed to drive through the TL box because some do not

As for that, it is the same as SC2 (the headphone cable that comes with the TI), so no change in that department.

 

[Failed Engineer]

The Star-8 is only for the TI, right? When will silver cables (and which models) be available again for direct drive amps?

 

[yyzSB]

Great timing on this new Star-8 cable. I was going to contact Danny about getting a second SR728 cable. I have setup 2 listening stations, 1 with the VM-1a in a bedroom and the KRELL Duo 175XD amp with the old amp interface box in my office. I was using the RAAL cable for the Schitt JR amp with both the KRELL and VM-1a and it just does not scale to the heights of the SR728. The cable is OK with the JR. I am too lazy to keep swapping the SR728 between the 2 listening stations so I will be lazy and get this new Star 8. (or SR728) .