Replacing Monarchy SE-160 Monos with Pass Labs X-150.5 - What to expect?

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c_morse

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Hey guys,

Just like the title, I have been looking to upgrade my amps for a while, originally intending on adding a set of Rogue Audio M150 Mono Blocks. Recently however, and through some reading, I have changed my mind and decided that I'd like to go with the Pass X150.5.

There are several factors that have led to this decision:

1) The Pass takes up less real-estate, requiring only one amp stand as opposed to two.

2) Less peripherals. One of my future plans is to upgrade all power cables, etc for my system. The Pass amp, being a stereo unit, will only require one upgraded power cable, versus two for the mono blocks.

3) It seems that the Pass unit pairs extremely well with Logans.

So, all this taken into account. Am I missing anything?

What can I expect upgrading from the Monarchy units to the Pass?

Any insight at this point would be invaluable to me. Thanks in advance!
 
The Pass gear is excellent and does mate very well with Logans. Depending on what speakers you are driving with these, your musical tastes, and how loud you listen, you may want to move a little higher up the range for more power (like and X-250.5). It can be useful to have a little extra power for those dynamic transients on high volume orchestral or rock music.

I have an X-350.5 driving a pair of Ascents, and couldn't be happier with the sound. Very smooth, with a hint of warmth. It retrieves details well, without being overly analytical, and it produces solid bass and crystal clear highs. It exhibits great dynamics, wonderful imaging, and a very musical sound overall. Can't compare with your Monarchy's because I have never heard them.
 
Pass is wonderful gear - can't go wrong. Only real issue is cost/watt. I'm a believer in high power *quality* amplification. So, depending on your budget and what kind of deals you can find out there, go for Pass if you can afford it. I've run Pass amplification in my HT for years and have never been left wanting.

Cheers and good luck.
 
The Pass gear is excellent and does mate very well with Logans. Depending on what speakers you are driving with these, your musical tastes, and how loud you listen, you may want to move a little higher up the range for more power (like and X-250.5). It can be useful to have a little extra power for those dynamic transients on high volume orchestral or rock music.

I have an X-350.5 driving a pair of Ascents, and couldn't be happier with the sound. Very smooth, with a hint of warmth. It retrieves details well, without being overly analytical, and it produces solid bass and crystal clear highs. It exhibits great dynamics, wonderful imaging, and a very musical sound overall. Can't compare with your Monarchy's because I have never heard them.

Rich,

I have a set of ML Summits. One of the things that I dislike about the Monarchy amps is that I have to turn the volume on my Pre pretty high to get what I consider to be a moderate amount of sound. I am thinking that I'd be much better off with the Pass, with that being one of my main things.

If I can afford an X250 or 250.5 when the time comes, I'm certainly game for that. I am hoping that even with the 150.5 I could drive the Summits a bit easier. I'd like to have the security of knowing I could crank the volume much higher and really drive the Summits, versus maxing the amps out early on.

I'm also wondering if maybe my choice in pres isn't a factor. I'm currently employing a Rogue Magnum 99 with HT Bypass, but was considering switching over to a Conrad Johnson. The only concern with that switch is I have to have a pre with HT Bypass.

Any recommendations? Or is the Rogue a solid unit that I can really count on?

-Charlie
 
Charlie, it may just be that your amp and preamp are not well-matched for each other. Without knowing more about them, I really couldn't say. I use Roger Sanders' (of Sanders Sound) Preamp with my X-350.5 and it is a great match. This is a very neutral preamp, which doesn't add its own sound signature to the signal, allowing the Pass gear to really shine.
 
I am going to try to get a X250 when it's time. I PM'd a member on here that has a X150.5 to see what his impressions are with his Summits. Just waiting to hear back. I have always heard really great things about the Rogue line, and that Magnum 99 Pre is a beast. It just seems, from what I've seen, that Conrad Johnson seems to be a much more employed pre on these forums. I would really like to go with a Pass pre, but (unless I'm mistaken here) none of them have HT Bypass. I am pretty set on going Pass for the amp though. The difference between what I should be able to sell my Monarchy's for and what a used Pass goes for is less than $1000. I can swing that quite easily.
 
The Pass X1 has HT bypass implemented with input 4. Given that the X1 is an older unit, I am pretty sure the recent Pass pre also has HT bypass. Here's an excerpt from page 6 the X1 user's manual:

The unity function too bears special attention. This control is associated only with input number 4 and has two positions selected with the up/down arrows. The up arrow toggles to a straight-through function with neither attenuation nor gain. This function is useful in that it allows the preamplifier to function as a unity buffer for use with components that best function with their own volume controls, such as surround processors.
 
Thanks Spike. I actually like the X1, so I might give that a try in place of the CJ Pre when I sell my Rogue.
 
Yes, both the Pass X2.5 Pre and X1 Pre have HT bypass input.

I would also suggest getting the bigger Pass X250 ($2200-$2500 used) or the X250.5 ($4400-$5000 used).
 
This might be a dumb question... not too sure. What is the difference between the 250 and 250.5? I'm guessing the 250.5 might be a newer model but is there anything else?
 
What is the difference between the 250 and 250.5? I'm guessing the 250.5 might be a newer model but is there anything else?

Yes, the latest model.

The Pass website states: The improvements are:

Cascode JFET Symmetric front end – input differential MOSFETs have been replaced by the same JFETs we use for the input devices on our MM and MC phono stages. They have very much less noise, higher input impedance, and greater linearity. They operate self-biased in a symmetric quad topology, each device cascoded and level shifted to form the full voltage gain stage of the amplifier.

More power output devices – Greater quantities of matched complementary power Mosfets operated as followers, giving more current and power handling, and also improved linearity.

New bias circuit – A newly developed bias generator has eliminated three sources of variation in bias current in the output stage. It also allows approximately 20% greater power output for a given supply voltage.

Single-ended Class A bias – The output stage not only uses a heavy bias current for push-pull Class A operation to a large portion of the rated power, but also has a single-ended bias source for single-ended Class A at low wattage.
 
Nice. Appreciate the info. Unfortunately on my budget I'd have to go with the older X250. I'll end up going with the X-1 preamp most likely, and then I'll go balanced interconnects. I'm just curious if the newer X150.5 would be better than the older X250.
 
Hit Bat,

I'd go with the 250 vs the 150.5. My sense is that you will hear the benefits of the power reserve more so than the newer technology.

FYI, I have a CJ preamp and will likely upgrade to a more current version in the not too distant future. Most, if not all recent CJ preamps, have an HT bypass so don't let that discourage you from considering CJ.

Also, if you do buy a CJ pre, all connects are single ended. I, for one, wouldn't worry about that limitation.

GG
 
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Thanks!

If I'm not mistaken, your 18LS is one of the few CJ's that don't have HT Bypass. I'm pretty sure the 17LS does. I will probably veer more toward the 250, especially after seeing how comparable their pricing is to the 150.5. The X-1 Preamp from Pass is reallllly nice. Then again so are most CJ's! Oh decisions, decisions...
 
I stand corrected!

Give me a holler when you're going to upgrade. I might just be interested.
 
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