Infinity 4.5 Redux, more questions

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Infinity nutcase.
Figured I’d start a new thread as I have more questions and would like to go more in-depth with these bad boys.

I’ve found a preamp that Really makes me happy so the base combo will be the Crown 2502, Adcom GTP-502 & the 4.5’s. First question, do you guys think 50 watts, 75 peak would be enough to power the 8 emims and emits to reasonable volume levels ? The unit I’m specifically looking at, Jolida JD302CRC because I’m getting a sweet deal on a like new unit.
upload_2019-1-31_2-5-25.jpeg

So I’d be biamping with the crown on the woofers, jolida up top. Any input here is appreciated, or maybe go with some sort of separate crossover?

Next question, the foam on the top baffle is deteriorating, time to replace it. I’ve looked on google and I’m not having much luck. I checked parts express and the panels I bought for the 2.5’s are to small to work on the 4.5’s, I’d like to keep it one piece if possible to keep the factory look. Anyone know where I can find some?

Lastly, I fired off an email to Graz. I got a pretty attractive response. Still I’d have to do it in two stages of 4 to soften the blow and the wife not kill me. This is a big decision because of what I’ve read. You guys that have done the switch I’d really like to hear your dead honest opinion about them, any listening fatigue ? Or otherwise ? My originals really aren’t in that bad of shape, just the standard waviness and a few with light surface rust.

Thanks Much.
 
I used a 25w tetroide and 50w in UL with no problems on mine, just depends how loud you want to listen to them. My stock foam face is still holding up well. knock on wood.
 
Yeah, I’m getting the Black Death Dust anytime I remove the upper grills so it’s time to do something. I ordered 48 wedge shaped panels for room treatment. I’ve seen a pair where someone used the egg crate foam and while I don’t like the look I guess if it works is what matters. I’m guessing the wedge shaped stuff could work but again how it looks matters to me.

So you think that’ll work, I guess I’ll give the Jolida a shot. I have no idea what tetriode is but it sounds ballsy !

I’ll throw a few pics up here soon.
 
If I had to make a choice for a EL34 amp on the mid/high section of an Infinity I would choose a Conrad Johnson Premier Four, One B or Fives.
The kind of amplifiers Nudell used on your speakers. In the States you can get a Premier Four probably for under $ 1,500.00.
The Four was the reference amp Bob Carver "copied" with his 'null difference testing' technique in a challenge initiated by the audio magazine Stereophile.
The Jolida JD302CRC is as far as I can see a integrated amp using two EL34 pentodes (not tetriodes or tetrodes) per channel.
I would go for something more beefier like the CJ's I mentioned.
Premier Four pic 2.jpg Premier One b top.jpg CJ PREM5 internal.jpg
 
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Ok Zara, looks like a good recommendation. Thank you and I’ll look into it when I get home.
 
I have a hard time believing they can sound 'better' then they do, except 'maybe' taming the high end a touch, They're definitely two of the finest speakers I've ever heard.
either way, I'm looking forward to demoing them more. :banana:
 
The Carver 4.0t works really nice on the top end, Bob tuned it to the CJ, and thier cheap. :)
 
The Carver 4.0t works really nice on the top end, Bob tuned it to the CJ, and thier cheap. :)
Haha, the original Carver amp that was used to be transfer mode functioned (that's what the 't' stands for) was the M1.0 with the CJ Premier Four as reference amp. All subsequent Carver amps retained the 't'.
Criticism from reviewers was that off the shelf they did not sound as the reference amp being the Premier Four or the earlier reference the Mark Levinson ML-2.
Only the amp in laboratory environment sounded similar to the reference.
I can't say anything about it's merits although I have had the ML-2's and Premier Fives (mono Premier Fours) but never a Carver 't' amp.
 

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So the Bi amping situation kinda took a backseat, I don’t know why but everything just sounds really good the way it is.

Which is a great thing I suppose.

The wood worker side of me, something I really enjoy has drawn up and completed a set of plans to re-configure the 4.5 drivers into a quasi Infinity Gamma configuration. No damage would be done to my 4.5 cabinets as all the drivers are just being pulled for the new cabinet.

So now I’m to the point it’s just a trip to Home Depot for the 3/4 mdf and red oak trim.

There’s a page on the net of 4.5 speakers that have been modified in different ways, one attempt at a gamma type is shown but it looks totally wrong to me. Mine will be much closer to the gamma with the 3 emims substituting for the big emim.

What do you guys think, waste of time and money or worth trying?

I’m really curious how much the sound would change with the bass drivers aligned and the 2 emims aligned above with the emits.

Go ahead and throw some criticism and thoughts at me :beatnik:
 
I ran a premier 4 on the top for like 20 years on 4.5 speakers.

Krell KSA 100 on the bottom. The midrange on the CJ is hard to beat. The bass and the top end are not all that much though. Your bass amp can take care of that problem, but you still have highs that will be the weak link. But you always have a weak link in a system. Always. You just alter where that weak link is.

The bigger problem you will have with that CJ is tubes. It eats driver tubes. 2 to 3 years max---if you get the sound you want. Eats them up. They are very picky on tubes and you have to go vintage. The only new tubes I ever used were worth a crap were the PSVane Grey bottles and the Shuguang Treasures. They cost as much as vintage themselves, or more, and they will fail on you---I had 5 of the 16 fail, through time. Most of the time they take out other parts so it's a repair thing as well. But I got tired of the escalating winged C cost---and they work very well but are not cheap. Highly reliable though. But the best sound I ever had was from the PSVane. And that was with the pricey vintage 5751's. The other pair of tubes it uses are sold by upscale audio for cj amps. Forget the designation, but like $70 each. Big difference switching to them.

And this goes without saying---you have to buy tubes from a top source. From the best dealers on the planet. Not just numbers off a tube tester. CJ will sell them to you---they have a 25% failure rate on sound on tubes that test well. You need 8 of them. So you are talking 8 driver tubes every other year from an Upscale Audio. Kevin is very good to talk to and knows this amp, by the way. I even tried RAM tubes once---they test tubes harder than anyone but I did not like the sound.

So re-tubing and getting that amp looked over and ready to go is not inexpensive. The cost to properly re-tube it and take it to a shop like every other year to look it over like I did, will approach your acquisition costs.

So that is the true cost of owning the amp. I've owned 3 Audio Research tube amps through the years as well, and they were far less expensive as far as eating up driver tubes.

Now for the good news---that CJ still has the best midrange. I cannot get it now----I have the heavily modded rs1b's now. With infinity subs. Tri-amped with Krell and Levinson. Same MIT 750 and 330 interconnects-----CJ really likes those cables and a Shunyata power cord as well, by the way The setup I have now does not have the midrange magic of the CJ. That 3rd and 4th vocalist. Female vocals. Air.

I am constantly tweeking looking for that CJ magic. I am maybe at 95%. With much more $$$$ thrown at amps & cables and magic bricks and so on. I fiddle with the crossover settings constantly trying to hit that sweet spot. Moving a cabinet over an inch. Adjusting things here and there.

Now like I said earlier, not hard at all to beat the top end of that CJ. But I could live with that. Those ribbons just hate a bright top end anyway and I've heard infinities with a bright top---makes me not like the speaker. So to me, less is better. So that might be an issue to you as well---that overly bright top with amps seemingly designed for box speakers with like a 1.5" single dome tweeter. But that is not Infinity. You have 4 times as much on those 4.5's.

So that CJ has high maintenance costs-----lets just say you are buying a 1992 jetboat. Still one helluva boat. But maintenance and daily costs are high. But you are getting it at a discounted price compared to new. Or think of what it costs to get a powerhouse 100 watt brand new tube amp these days---you are like 15 cents on the dollar. So pay for the tubes once in a while. Those 4.5's flat out love that amp.
 
Thank you rdka for the in depth info. Agree with you on the tubes, I only buy from upscale as I’ve has nothing but stellar service and good quality tubes.

One thing I can’t argue is the 4.5 is pretty hot on the top end, but I will argue the case that that really doesn’t come into play until you start cranking them up. For me at least having some pretty good time listening now is that normal listening levels.....say not more than 1/2 on my volume knob they sound very good. I put my symphonies tube preamp back in which has no level controls on it, 3 gold lion tubes and one rectifier tube. Once I go over 1/2 on the volume things start to heat up.

So I’m still undecided on the preamp, I’m constantly searching and researching and coming with the approach that I’m going to buy once, cry once. My only real requirement is that the unit have a remote control.

I’m currently watching an Odessey on ebay and may have a go at it.
 
Speaking of gold lions--they do well on that Premier 4. Not great, but pretty well. A good value for the dollar kind of thing. Tube failures with them though. The thing to remember is the fact that big high power tube amps simply have to have a lot of tubes. Aren't too many manufacturers making tube units requiring 8 driver tubes. Let alone when changing tubes---especially buying some you don't care for & replace quickly. Ouch.

Lots of folks have amps with the grand total of 4 power tubes. Big difference in expenses buying 8. Plus the failure factor with having 8 tubes is a whole lot higher than it is with just 4. 8 good tubes from Kevin @ upscale is not inexpensive. But his tubes don't fail. And he knows the right one's for the amp you have.

It is so tough buying things now for system compatibility. Synergy. It is a guessing game to a degree and throwing money at it is a simple and easy thing to do. You can get the numbers part of things easy enough, but how it matches up with your existing electronics and cables and so forth is really quite hard. And having the ability to play everything together is pretty much non existant. Kevin is a real good guy to talk to about that. I use to talk to Harry at VPI also & he was always the best.
 
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