Sonic difference between 4 ohm and 8 ohm taps

[ccmccull]

I decided to give the 8 ohm OT taps a try today with my Spendor 3/5r2's. According to stereophile, these are 8 ohm nominal with a dip down to 6.2 ohms in the lower midrange.

https://www.stereophile.com/content/spendor-s35rsup2sup-loudspeaker-specifications

I didn't notice a huge difference relative to using the 4 ohm taps. Maybe slightly more articulate bass, but I'll need to do some real A/B tests to convince myself. What should I be listening for?

[Paul Birkeland]

That's a pretty minor dip and not necessarily broad enough or low enough to necessitate the change from 8 to 4.

Going from 4 to 8, you will get more power, less damping (looser sounding bass), and slightly higher distortion. 

[ccmccull]

Thanks Paul. I'll live with it for a while on the 8 ohm taps and see what I think.

btw, I was thinking the 8 ohm tap might bring back the 60 hz hum on my grados that I discussed with you previously. But it did not. The 8 ohm / 2 ohm L-pad on the headphone jack seems to do the trick with the 8 ohm OT tap too.

[ccmccull]

Reporting back. 4 ohm definitely the way to go for my system. Yes I have to turn the volume pot up 20 degrees or so. But at 4 ohms the music is more present and dynamic. As I've written before in this forum, this amp eerily brings instruments and singers to life in the room. On the 8 ohm tap that talent diminishes slightly.

Example track: Paulo NutinI - Lose It. On the 8 ohm tap it sounds great. On the 4 ohm tap you can see the pick on the bass guitar string. Then the low A (55 Hz) is effortless. Then the drum enters the room. It builds and builds. Wow.

[Mucker]

FWIW, I use the Doc recommended 4 ohms. It drives my DT-1990 Pro, HD600, Aeon RT,  and HiFiMAN HE-6se V2 exquisitely. IMO, the S3X is the one of the best headphone amplifiers ever created. I honestly don't know how it could be better. So much thought put into it's design. Think hidden GEM or equivalent IMHO and really fun to build.