Seriously, What the Hell? Shouldn't They All Sound the Same?

[1audiohack]

Howdy All;

Well, a year and about eight months later the UREI has been in the office rack unchallenged, and it has been very thoroughly enjoyed.

A couple of months ago I bought a very nice Crown Studio Reference II from its original owner. I have wanted one for a long time and being assured that it is functionally perfect and not wanting to chance it going bananas on auction, I paid the too high buy it now and eagerly awaited its arrival.

It shows up well packed and looks great, not perfect but very clean. A quick VOM test show nothing to be concerned about so in the rack it goes, and, dead channel. Nice.

The seller agrees to pay for it to be repaired based on the AE Techron estimate so off it went to the best outpost of the Crown mothership.

Turns out that is has cracked solder joints on the driver transistors that are mounted on the output board. Cracked in shipping, well,, maybe. While it was there, I asked them to really run it to be sure that all was as it should be.

It came back this week and tonight it went back in the office rack. After an hour or two I do like this amp. It will take me a couple of weeks to really get to know it but so far all good. It is bright, in a nice way like the SAE2400 so maybe the UREI is a bit subdued in the UHF.

I am going to have to re rack the UREI so I can somewhat quickly swap back and forth. I really like them both.

In a couple of weeks after a good long test here I will take it home and light up the Everests or the 4365's with it.

All my best All.
Barry.

[DerekTheGreat]

Funny, you got your SR-II back in gear about the same time I got mine in gear. Damn thing is the heaviest amp I ever want to hustle around, screwed up my wrist playing with it over the weekend. (Getting old sucks, youth is wasted on the young) Anyway, my personal rant aside, the thing is killer on bass, my personal benchmark thus far given everything I've heard and played with. However, I have yet to test it above 90hz or so. That was supposed to happen today or tomorrow, but that'll have to wait until I can take off this brace on my wrist..

[BMWCCA]

I'm enjoying mine, even if I never quite got it in a rack!

[DerekTheGreat]

I don't have a rack either, can't seem to find any that aren't all industrial looking.

Nice filter, what do you use? I had AE Techron replace the rotting original in mine, but it doesn't look like much of a filter and doesn't sit flush after a day or so.

I also noticed your power switch is out (off), yet the ODEP lights are still on. That's exactly how mine behaves.

[BMWCCA]

I don't have a rack either, can't seem to find any that aren't all industrial looking.

Nice filter, what do you use? I had AE Techron replace the rotting original in mine, but it doesn't look like much of a filter and doesn't sit flush after a day or so.

I also noticed your power switch is out (off), yet the ODEP lights are still on. That's exactly how mine behaves.

I bought a bulk roll of ATV air filter medium and cut it to fit. Seemed to match the deteriorating original very well. The lights, as I understand from the manual, simply indicate that the amp is plugged in to power and ready to be turned on. Mine came to me with satin-aluminum knobs and the ones in the photo are the clones from Ali-Express! Fit perfectly.

Now we need to find someone with the end-caps so we can have them 3D-printed.

[DerekTheGreat]

Awesome, I'll look for some.

Oh really? I went round and round over that. Because when I start with the amplifier off and plug it in, no lights are on the display. When I turn it via the front switch, it does it's thing and you can listen to it. Then when I turn it off via the switch, it'll shut off the red indicator light and such, but the ODEP lights stay on. I couldn't find a passage in the manual which states that's normal, person at Crown said, "..There aren't any gray beards left to verify that amp's operation.." and AE Techron's tech told me that was normal. However, there's another gentleman with several of these who says his ODEP lights go out when switched off via the power switch. My power switch has since been modified such that it's always on or pushed in.

I was able to locate a supplier who is selling power switches for these (I was told they are NLA). I bought one, but don't see myself replacing the one in mine unless I sell it, as I use a sequencer to turn everything on or off anyway. Also, the black button has been glued to a broken portion of the switch. I don't think there is any way to safely retrieve it such that I could put it on the new switch. Would you happen to know if an identical or very close replacement exists?

Yes to the caps! My amp is missing them, would love to have a set.

[Wayner]

I have caps and can work on making a model for 3D printing. Typical, I suppose, but I'm missing one cap out of eight. As to the original thread... My story is based on 250TI. I started powering them with a PL4. Thought it was pretty good until I connected a SA2 (PSA). Thought that was better, except for the fan noise from the SA2. So I connected two PL4s in bridged mono mode. Thought that was better. Then I swapped in two Studio Reference II amps (mono) and I think its still better. For me, a key improvement is the noise floor reduction. I also think the 250TIs benefit from all the power you can provide them. I kinda doubt I had the same sound difference related by the OP. And I think the amplifier progression I went through isn't exactly comparing "similar" solid state amps. But my listening enjoyment did take a jump up with each change. But I'm certain my listening impressions are biased. I doubt I could differentiate in a proper blind a/b. But, you know, I like to think I can. And on to an only slightly related question. I've been powering my M2s with a pair of Studio Reference I amps. Blu-50 providing DSP. One of those SR I amps recently faulted. It requires service or maybe even replacement. Do you think using a SR II on the top end and SR I on the bottom would be okay? I don't have any experience mixing amps, even though it seems people do it all the time. For what it's worth, I tried a CDi 4/600, 4/1200 and 4/2400 amp on the M2 and preferred the 4/1200. 4/600 didn't seem to have enough power and 4/2400 was just ridiculous on fan noise. The SR I gives me 750watts/channel, 120s/n and no fan noise. It's fabulous. All this makes me think the M2 likes >600watts and so I wonder what 350watts would be like on the top end only.If it turns out anyone wants to comment on my SRI / SRII question and it derails this thread, I'll gladly move it to its own thread. But I get pretty excited when anybody wants to talk about Studio Reference amps.

[1audiohack]

Hello All;

I don't have any issue at all drifting into other amps here. That is built into the premise of the thread.

My SRII has the end caps. I can scan one and print them if that's what you want. I could machine them but there is a very small "nearly not" radius in the two inside front corners that would be difficult to cut.

Derek when I power my SRII off with the front switch all lights immediately go out and stay out. My SN is 00076 if that means anything.

Wayner how close to going zero dB on the SRI do you ever get? I am pretty sure that the SRII will satisfy the top end of your M2's. If the input sensitivity is set the same as your SRI there should be no level difference until you approach the last three dB of headroom in the SRI. You are only dropping from 78V to 53V right? 175 Watts into the D2's ≈16Ω impedance ought to work I think. Using the SRII you are really only 3dB down from the suggested amp, the ITECH 5000HD that will deliver 100V per channel.

Barry.

[DerekTheGreat]

I have caps and can work on making a model for 3D printing... ...I've been powering my M2s with a pair of Studio Reference I amps... ...One of those SR I amps recently faulted. It requires service or maybe even replacement. Do you think using a SR II on the top end and SR I on the bottom would be okay? ...But I get pretty excited when anybody wants to talk about Studio Reference amps.

I'm pretty excited about these amps as well. Today I should have my SRII switched out from bottom to top. I noticed the noise floor is much better than before, but that could be because the transformer in one of my PS400's has a hum. The 2245H's the PS400 was powering are quiet. But now, with no transformer hum, the entire system is dead quiet. If you'd like to sell your dead SR-I, I'd be interested in it. 755 watts into each of my 2245H's should satisfy my power requirements and SPL goals

Hello All;

I don't have any issue at all drifting into other amps here. That is built into the premise of the thread.

My SRII has the end caps. I can scan one and print them if that's what you want. I could machine them but there is a very small "nearly not" radius in the two inside front corners that would be difficult to cut.

Derek when I power my SRII off with the front switch all lights immediately go out and stay out. My SN is 00076 if that means anything...

Barry.

I'd love a set of caps whenever you can get around to them, as well as some suitable fasteners if you could source them or point me in a direction where I could find some! Let me know how you'd like to be compensated when the time comes. Not even sure why mine are missing, like, why take them off?

Also good to know how your amp operates. The OCD sickness in my brain is kicking me for not having that defect in my SR-II repaired while it was on the bench. The potential total cost is what deterred me from pulling the trigger though, especially since it works fine otherwise and is still operating like the day it was made.

[BMWCCA]

My ODEP lights have always stayed lit when the power switch is turned off. I'd have to unplug and re-cycle the amp to see if they come on as soon as it is plugged in, or only after being powered up by the switch. Here's a section from the owner's manual. Interpret this as you will:

ODEP: Each channel has an ODEP indicator that shows the channel’s reserve energy status. Normally, the LEDs are brightly lit to show that reserve energy is available. In the rare event that a channel has no reserve, its indicator will dim in proportion to ODEP limiting. An ODEP indicator may also turn off under other more unusual circumstances (see Section 4.3).

[1audiohack]

I have a fuzzy memory of reading somewhere in the manual that if the amp was connected to power and the rear breaker was in the on / connected position the ODEP lights would stay illuminated but I would have to be read it all to be sure. I only know how this one amp behaves.

You have to have the end caps off to install rack screws and if the front of the rack side panels are deep enough to safely cover handles and knobs on the front of components you would not be able to access the side screws to reinstall the end caps. I have movable racks built in this manner and can see how the end caps could get forever separated from the amp. Bummer for us.

I will scan a cap and see if I can print a good part.

Barry.

[DerekTheGreat]

My ODEP lights have always stayed lit when the power switch is turned off. I'd have to unplug and re-cycle the amp to see if they come on as soon as it is plugged in, or only after being powered up by the switch. Here's a section from the owner's manual. Interpret this as you will:

I have a fuzzy memory of reading somewhere in the manual that if the amp was connected to power and the rear breaker was in the on / connected position the ODEP lights would stay illuminated but I would have to be read it all to be sure. I only know how this one amp behaves.

I found that as well (not the part Barry found), but of course nowhere in the manual does it detail start up and shut down. I just thought it was strange given that when initially plugged in with the breaker in the "on" position but the front switch off, no lights on the display. Push the switch in up front, goes through it's deal, power light remains on as well as ODEP lights. Push switch again, every light goes out except the ODEP lights. I haven't tested for voltage at the speaker outputs though, especially if a signal was being fed to the amp.

...You have to have the end caps off to install rack screws and if the front of the rack side panels are deep enough to safely cover handles and knobs on the front of components you would not be able to access the side screws to reinstall the end caps. I have movable racks built in this manner and can see how the end caps could get forever separated from the amp. Bummer for us.

I will scan a cap and see if I can print a good part.

Barry.

Ooooh, that makes sense now. Bummer indeed. Thank you, Barry! Would be much appreciated.

[BMWCCA]

On missing end-caps, I figure they were a pain in the ass to deal with and since these were used by professionals who couldn't care less about how they looked in their rack, they just didn't have time or patience to fuss over the damn caps.

[Triumph Don]

I'm enjoying mine, even if I never quite got it in a rack!

Is that what you use for the bottom of your 4345's?

[BMWCCA]

Is that what you use for the bottom of your 4345's?

No, I actually got it for the 250tis that are also on the project list (woofer surrounds). The 4345 seems to work just fine with a PS-200 on top and a PS-400 on the bottom. Never seen any lights come on so I doubt they're working very hard. When I bought the 4345 that was my concern but New Horizon told me the 18 had the same motor/magnet as a 15 and not to worry. He was running them on Haflers—well named since half of his seemed to be broken.