[aokman]

Frankly, the og srd-7 is pretty trash imo. Works OK for $500 cans but I'd skip.it past that. Woo wee (if you do the bias mod) is probabaly the best bet for less than iesl imo

They're decent when you modify them with 4.7ohm series resistors and gut it out but the HF fall off and bass distortion doesn't make them ideal, I just finished doing a lot of testing vs Lundahl stuff. But yeah I wouldn't use an SRD-7 on anything past Lambda's personally...

 

[goldwerger]

@iFi audio is seems you can take the survey from the top here, clearly you decided your direction (whatever we may think about it). Unless you may still surprise us with an iESL v2, though it seems unlikely?

 

[aokman]

The product page is up… Man it’s a wild design, a lot of work must have gone into this. Would love to benchmark it sometime… The price though…

https://ifi-audio.com/products/ican-phantom/

 

[573531]

The SRD7 pro mk2 with dedicated bias (not the SB) is way better than what people make it out to be. I doubt the difference between lundahls and it is audible in a controlled test.

 

[eskamobob1]

The SRD7 pro mk2 with dedicated bias (not the SB) is way better than what people make it out to be. I doubt the difference between lundahls and it is audible in a controlled test.

You'd be shocked then. Transformers have massive measurable impacts on distortion level, profile, and even frequency responce. The step from even mjolnir srd-7 to something like woo wee is honestly massive even with lower end amplifiers (and wee is cheaper so you know I'm not just being biased by cost). Like I'd pretty easily req someone go emotiva bass X with wee over even a 1-2k amp with srd-7 pro

 

[aokman]

The SRD7 pro mk2 with dedicated bias (not the SB) is way better than what people make it out to be. I doubt the difference between lundahls and it is audible in a controlled test.

It depends what version you have… They made a lot of them and there are variations with different winding ratios, some with 27ohm resistors (perform good) and those with thermistors (hot garbage). I have 3 SRD7s and all are different…

The Lundahls are a significant improvement but not comparable to an off the shelf SRD7 anyways as you cannot buy them in a retail product currently…

The handy part about SRD7s is you can buy normal bias versions for cheap and make them pro bias with a little soldering skill and redo the resistor configuration. They really need an isolation transformer though.

 

[eskamobob1]

They really need an isolation transformer though

I had forgotten about this. I have a power conditioner I esentialy just use as a power strip to protect my gear. Srd-7 is the only thing I've heard any kind of decent difference from plugging it into my ultra noisy mains VS the conditioner. None of the other transformers I've tried have mattered tbh

 

[573531]

You'd be shocked then. Transformers have massive measurable impacts on distortion level, profile, and even frequency responce. The step from even mjolnir srd-7 to something like woo wee is honestly massive even with lower end amplifiers (and wee is cheaper so you know I'm not just being biased by cost). Like I'd pretty easily req someone go emotiva bass X with wee over even a 1-2k amp with srd-7 pro

Again there’s a massive exaggeration of this. I tested mine with the best of my ability at that time to replicate a realistic load, and got basically inaudible distortion.

 

[aokman]

I had forgotten about this. I have a power conditioner I esentialy just use as a power strip to protect my gear. Srd-7 is the only thing I've heard any kind of decent difference from plugging it into my ultra noisy mains VS the conditioner. None of the other transformers I've tried have mattered tbh

Yeah the bias line is very sensitive to line noise and seems to resonate through the diaphragm. The pro bias conversions I did using the STAX schematic have audible hum from the power bias supply, depending on the amp used. Not to mention the sketchiness of having mains coupled bias on your head…

I abandoned it with the Lundahl setup for a fully isolated DC-DC regulated supply with an isolated ground.

 

[aokman]

Again there’s a massive exaggeration of this. I tested mine with the best of my ability at that time to replicate a realistic load, and got basically inaudible distortion.

It depends how you look at it really… The transformers themselves are bad performers if you directly drive them with no external mitigations, their FR is bad. Once you add resistors, they clean up quite well per the graph I showed above… The Lundahls will perform brilliantly directly driven as is.

You cannot assume all SRDs are the same either by looking at them externally also and measuring distortion at say 200Vrms is problematic.

 

[eskamobob1]

Again there’s a massive exaggeration of this. I tested mine with the best of my ability at that time to replicate a realistic load, and got basically inaudible distortion.

What tests were performed exactly? What do "realistic load" and "inaudible distortion" mean in this context? Your comment gives 0 info other than that toy disagree but done appear to have tried the comparison (you're free to think what you want obviously).

 

[573531]

It depends how you look at it really… The transformers themselves are bad performers if you directly drive them with no external mitigations, their FR is bad. Once you add resistors, they clean up quite well per the graph I showed above… The Lundahls will perform brilliantly directly driven as is.

You cannot assume all SRDs are the same either by looking at them externally also and measuring distortion at say 200Vrms is problematic.

How did you do your measurements? If I have time I will try to replicate and post what I get.

 

[eskamobob1]

How did you do your measurements? If I have time I will try to replicate and post what I get.

Nice dodging my ask for clarification

 

[aokman]

Here's some of my data, I haven't gone in depth as it was just a side quest for my Lundahl project as a comparison, but I tried various loads aside from my scope and meter impedance also. I'm not crapping on the SRD's, they do the job I guess to a point and are a great entry point if you can isolate them and get pro bias but it can be taken further with better transformers

There is some weirdness in the bass region also with sine wave deflection as the transformers are quite small but cannot capture it accurately with my equipment aside from what I "see" on a scope.

120pF capacitor
150k resistor + 120pF capacitor (Series)
150k resistor + 120pF capacitor (Parallel)

 

[573531]

What tests were performed exactly? What do "realistic load" and "inaudible distortion" mean in this context? Your comment gives 0 info other than that toy disagree but done appear to have tried the comparison (you're free to think what you want obviously).

A load with similar impedance as a typical stat headphone but still I need it to be a voltage divider (to save my analyzer input) so I have a mathematical consideration, and inaudible distortion to me Personally is everything under the maximum cd quality dynamic range since I only listen to tidal cd quality. Now rip on.