kippy

Thanks @chronometers for the note. In between my original posting and now, I had my mc-225 serviced by John Warren. It sounds lovely. I then took a chance and purchased a second mc-225 to use for LF duty on my Jubilee speakers instead of my mc252 amp (250 wpc). I was surprised to find it sounded terrific. I don't miss any bass from the Jubilee and it really balanced the sound. I sent it off to JW for servicing a few weeks ago. I would not have expected at the start of this audio adventure about a year ago that a pair of mc-225 tube amps would end up sounding better than anything else.

I posted an architectural drawing of the room further up in this thread with all the layout if you want to see it. Since my last post, I switched to using a pair of mc225s and the system is plenty loud even at moderate volume. At the risk of angering the gods of thread monitoring, I won't say much else on the topic of tube amps in a class D thread.

It's been interesting reading this discussion. I live in the SF Bay Area and was lucky enough to visit the sound exhibit at SF MOMA. I had never heard an OJAS system before and spent a bit of time there. It looks quite impressive and sounded pretty good. Better than most I have heard. People seemed to be engrossed in the experience; perhaps because most had never heard horn-loaded systems and tube amp combos before. My impression was that it sounded a bit sharp. I kept thinking to myself that all the expensive equipment in the world and all those hours spent building it, constructing it and each experience is so very subjective. Maybe my ears are off, but I had to leave after a while. I am really glad to have experienced it. I am not taking something away from Devon and OJAS. I have arrived at similar lessons reading the posts here from all the old school guys talking about horns, low-powered amps, second-order harmonic distortion, etc. So much knowledge being offered up and shared. Maybe it's fair to say that Devon has mastered the approach to capturing the imagination of sound hipsters and the companies that want to sell products to them. If that brings more eyeballs and interest to Klipsch, then all the better. I want this company to thrive and survive.

I've heard so many good things about the old McIntosh amps, glad to hear you are enjoying your MC30s and MC240s. We are lucky to pick between diamonds and pearls.

I will read through you thread and adventure. Room is 660SF, 8' ceilings so I think about 5280 cubic feet

You want to know something embarrassing? When I got the Heritage Jubilee speakers, I didn't ever bother to notice that the HF horns have a 16ohm nominal impedance. Yesterday, I switched them from the Mc225 8ohm taps to the 16ohm taps and the sound was clearer/brighter (but not sharper). Did it sound pretty good using the 8ohm taps on the MC225? Yes. Did it sound pretty good using the default taps on the J2? Yes. You asked about the room size; here is the exact config. Speakers are on either side of the french doors in the family room. Floor is concrete with thick padding/carpet. Back and side walls are concrete retaining walls.

Thanks kindly! I thought the system sounded better than anything I had previously heard but I have since worked on iterating on all the different parts of it to arrive at something even better. I've been the beneficiary of all the wisdom on the forum from various team members and I have iterated on the following in roughly this order - amps (feel like mc225 is ideal for HF but First Watt has also sounded great) - preamps (settled on my Bozak mixer) - dac (moving from Bluesound nodex to NAD C658) - dirac use (about to start experimenting when it arrives next week) - room tuning (wow - what a difference bass traps make in clearing up muddy bass) I intend to write up my diary of experiments and share but I feel like half the magic is the speakers and the other half amps, room, room correction, etc...I'm not there yet but it sure is fun getting there. best, Sasha

Theoretically no, but I have been doing a lot of experiments over the last month or so and sometimes I turn the sub off and sometimes I turn it on and play with the curve/filter. I'm still up in the air to see if I keep it.

Great question and this what the wise and kind @mikebse2a3 suggested privately! I tried both 4ohm and 8ohm taps yesterday for a casual (but not loud) listening session but did not run the music up to 105db; I'll give that a whirl and let you know what I discover. I was using the 8ohm tap in the previous test. WRT another MC252, I am fortunate enough to have two here I might run that test as well and see what happens with an MC252 dedicated in mono to each channel. BTW, using the 4ohm tap (instead of the 8ohm tap) in my casual listening session resulted in a softer bass thump from the Jubilee speakers. Switching back to the 8ohm tap sounded better and more powerful. I can see where listening to jazz or something that doesn't really need that tight thump might be better with a 4ohm tap connected to the LF cabinets.

This is a very interesting statement...why do you hate Class D if they are to your point, convenient, quite, damping, powerful...

I'd like a McIntosh whose volume knob goes to 11

It was bonkers loud and I rarely play it at that volume. Meters were pegged and power guard kept flashing Sometimes it's fun, lol.

So just to be succinct, the LF cabinets don't "clip" or distort and neither does the McIntosh amp. I would guess one could throw more watts at the Jubilee LF cabs and they would play at their 300/1200 watt nominal/peak rating. It's the McIntosh amp that was running out of juice and the sentry/powerguard kicking in when the DB meter hit 105db and the wattage was pegged near 250 watts on the McIntosh display.

The McIntosh sentry powerguard kicks in; I don't hear actual clipping on the McIntosh. I was fast and loose with my language. I measured the DB on two devices at the same time (Decibelx on my iphone and a physical meter). The McIntosh meter was hitting 250 watts/channel as well.

I have been researching Class D amps lately and it's been a rather fun research project to read through a decades worth of everyone's collective experience here. Do Class D amps generally provide a tighter bass response than say a McIntosh MC252? I am running a pair of Heritage Jubilee' speakers. I have an MC225 on HF duty and the MC252 on LF duty. Bass is thumpy but slightly muddy. I am exploring DIRAC to help solve room issues but also wondering if a Hypex NCx500 would sound any different than the MC252. I have already discovered that even though the Jubilee LF cabs are very efficient, they begin to clip at about 105db...yes, that is loud and I rarely listen at that volume, but every once in a while I like to scare the neighbors.