"Shortest Way" SW51 Amp Impressions (Simple SET Amp)

Large thanks to @rhythmdevils for setting up this loaner tour. First time trying out the SW51+ and I am impressed. Better late than never, but wish I had tried for one of these sooner!

I don’t have a whole lot to add to the glowing reviews of the SW51+ other than that I really enjoyed my time with the loaner. I was lucky enough to have friends on the forum that would lend me some headphones that would make the most of the time I had with the amp. Namely a set of black screen HD650s, a set of FP HD580s, and a set of JAR650s.

First off…the amp is much smaller than I was expecting it to be. Fit and finish are nice, and the connection jacks are solid. The volume knob is not my favorite choice in texture or size, but it is functional and works. I like the cat logo on this particular model, and it was a nice size on my desk. For reference, most of the listening was done using a opamp modded modi mb.

The SW51+ with stock tube setup was simply a pleasure to listen to. It was a listening experience that reminded me of the 3F and Focal Clear, but for a significantly lower cost. Each of the headphones had its strengths, but perhaps the best was the HD580. I had owned two other HD580s in the recent past and neither had the magic that I was hearing in this setup.




The only amp I had onhand for a comparison was the ECP Black Diamond Proto and compared to the SW51+, stage is narrower and overall tonality was drier. The ECP has more raw power, but is on the same level of detail retrieval. Stage width and layering capabilities go to the SW51+. The ECP is better at absolute bass impact, and with the ESX900 gives more of the tactile feel in the low end.

I enjoy a broad range of music and have been on kind of a piano binge lately. My favorite part of piano tracks is listening to the non-musical sounds of the piano, like the pedals being manipulated. These subtle sounds within the musical tracks help to transport me to the venue or studio where the music was recorded. The SW51+ clearly pulls out those small details and adds them to a nice wide stage for a very immersive listen. The ECP amp portrays those same micro details, but does not spread them out as wide or deep.

I would sum up the sonic experience as organic and rich, but those terms are really just a strange way of saying that I really loved listening to the SW51+ and the assortment of Senns, that I had on hand.



Bonus Points: The SW51+ gave life to the Focal Clear MG in a new way. The recessed mids were gone and the overall FR was much more to my liking. Also, ESX900 was a great match out of the LI port. This amp really seems to be able to handle a lot of different phones.

Low Points: Power is on the low side, low enough that I could max out the volume knob on the Senns, but that was very loud listening. The benefit of this low power might be that it works very very well with the ESX900 and was a stand out pairing that was unexpected.

Tube options: I am trying to rid my life of the tube rolling game and the SW51+ is a prime candidate for it. I swapped out the stock for the RFTs and did not notice a huge difference in the time I had the amp. The tonality of the amp is just so rich and easy going that I didn’t really bother trying to compare.

I will be on the lookout for a SW51+

 

Interesting, stage width/size has been reported as a weakness of the SW51 IIRC. I don't find it to be lacking myself.

Either your source material is very quiet, or you listen REALLY LOUD

 

Agreed. I'm testing the exact same unit with my modded senn 6xx. With DR10 materials, vol knob is pretty much 10am -- around 3 major units.

On the staging front, I didn't find stage size weak, either. I kinda think OPT never lacking in this criterion by nature.

 

Same here. 9:30/10:00 is loud enough for me.

Maybe the source is held back/low?

 

I think most of my listening was right around 11 on the dial. But i didn’t find much gain going from 11 to full power. Maybe it was the piano music, but I am not an overly loud listener. Could have been a SYS in the setup, but i don’t remember and that would have been set to max.

 

Re. stage width, I don't find it lacking, either.

In my chain of Bifrost 2 -> SW51+ -> HD 600 I find that it's not so much that the staging is wide and spacious as it is that sounds pan quite far over to the left and right. It's more a matter of imaging, then. This has a slightly unusual effect but one that's pleasing and that helps with instrument separation.

 

swapped the Telefunkens for Mazdas yesterday - well, these are some rock'n'roll tubes! first had a listen with TR-X00, presently listening with HD650 - as expected, I find the synergy better with HD650.

oh, and by the way, I am listening at 13:00 pretty much all the time, sometimes tuning it down a notch, sometimes up. but I do enjoy my rock'n'roll loud. discovered Benjamin Booker yesterday.

 

A couple of thoughts
1. Piano stuffs typically have 1) large headroom to FS and 2) low rms level (either short or long window). So it's possible you may need more decibels compared to modern edm (DR10 or less + almost 0db headroom).
2. I believe most SYS users who use it as a switcher set the volume max (= no attenuation).

 

On this same sort of topic, did folks ever decide what the "ideal" setting on the volume knob of the SW51+ is if you are controlling volume at your preamp? (in my case at freya+). 100% on the volume knob of sw51+ OK? I could not really tell a difference when I experimented, but I figured maybe there is a technical "best".

 

100% on SW51. If you're controlling volume externally, you don't want attenuation at the amp. Unless the amp's noise floor is audible, then back it off till it goes away.

 

When I used a SW51+ with my Saga or a Goldpoint passive I always set it to 100 on the dial and never had any performance issues.

 

I set my amps for unity gain and then control externally with stepped attenuator (Goldpoint SA2-47.) When switching between amps I will always achieve the same SPL with the same stepped attenuator setting. Makes comparisons much easier and more reliable.

 

Thanks for the quick replies everyone, two great approaches. Will try 100% and make sure I don't have noise floor issues. But will also mess around with where unity gain is with my First Watt F7-LS3/5a setup is so I don't accidently blast my ears switching between setups.

 

It surely must be preference thing, but my policy is to avoid too much attenuation on a single device with potentiometer. I kinda think -35db is where things start to conflict unless ultra-uber pots. Even if so, it can cause subtle imbalance by nature.

 

My impression originally posted here.. but realized there was a better thread (as announced in OP as well).

So the post moved to the newer thread: https://www.superbestaudiofriends.o...-amp-impressions-only.8363/page-9#post-378326

 

Which Mazda variant?

 

6F23 (EF812)

 

I need some new tubes for this amp. A local dude has Mullard EF184's for a fair price, NOS, tho not matching batch etc.
How important of a factor is this?

 

I asked Zampotech a bit ago and he said you want to use matching tubes.

 

I bought some Mullard EF184 NOS, probably not matched. For sure notice their bass!
I find them to be so-so with more complex music- I sort of see the "like doing coke" as someone has mentioned in this thread. $60 for a pair of matched RFT EF184... Ok price?