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Ittaku

Amateur OB speaker builder and his ARC based digital system

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Mate, there are reasons I'm stuck in this room, trust me. It's not like I want to be.

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Yes yes, I know you told me so... 

I truly believe that one day it will get the space it deserves, just enjoy for now. 

 

Having said that, I had a similar situation back in home town, since we were sharing houses with the elderly folks... Just to prove a point, I when everyone was away, I actually moved the entire system out into the main living room, Apogee's, monoblocks the works! When they got home, they all looked very surprised and a bit annoyed that I had done this. However, I gave them a demo and that's all she wrote! 

That particular system stayed there until I tied the knot with the wifey and bubs popped out! That system continued to stay there even after we migrated to Aus... Eventually my old pops (82) at the time, managed to sell it off to a well deserving trusted customer of ours who became a close family friend.

 

Perhaps you could try this out, not too sure how your Mrs would react but you never know. Worst case scenario just move it back, after a few years... Ha! 

Cheers, have a good one. 

RJ

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Finally had the rectifier tube in my preamp go today. It didn't blow the fuse as I'd expected it would but there was a not very nice sounding vibration coming from the power supply, so I doubt it was doing the right thing and was not doing the rest of the electronics any good so I changed it immediately to a replacement and it went away. So that's 3000 hours almost exactly on the clock for that rectifier and I've replaced it with exactly the same sort of Sovtek 5AR4 since it worked so well for me.

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4 minutes ago, Ittaku said:

Finally had the rectifier tube in my preamp go today. It didn't blow the fuse as I'd expected it would but there was a not very nice sounding vibration coming from the power supply, so I doubt it was doing the right thing and was not doing the rest of the electronics any good so I changed it immediately to a replacement and it went away. So that's 3000 hours almost exactly on the clock for that rectifier and I've replaced it with exactly the same sort of Sovtek 5AR4 since it worked so well for me.

 

Rectifiers often work very hard and hot.   Not sure how much your preamp pulls off the HT supply, but this is a 300B style Supratek?  Maybe the 5AR4 did well for those 3000 hours.  Good that nothing else was damaged when it went.

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Just now, aussievintage said:

Rectifiers often work very hard and hot.   Not sure how much your preamp pulls off the HT supply, but this is a 300B style Supratek?  Maybe the 5AR4 did well for those 3000 hours.  Good that nothing else was damaged when it went.

No, it's not a 300B style. It has 6L6GC regulation after the rectifier and drives nothing but 6SN7s. The documentation said the rectifiers should last about 2000 hours and once I got to 2000 I asked Mick if I should just change it on spec. He said not to worry, and just keep using it as it would just stop working but take out the fuse at the same time and not damage anything when it failed. I managed to get 50% more life out of it, but it did not fail in the manner he expected - though perhaps if I let it keep running that way it would have eventually, but the behaviour was concerning enough for me to not take my chances.

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1 minute ago, Ittaku said:

No, it's not a 300B style. It has 6L6GC regulation after the rectifier and drives nothing but 6SN7s. The documentation said the rectifiers should last about 2000 hours and once I got to 2000 I asked Mick if I should just change it on spec. He said not to worry, and just keep using it as it would just stop working but take out the fuse at the same time and not damage anything when it failed. I managed to get 50% more life out of it, but it did not fail in the manner he expected - though perhaps if I let it keep running that way it would have eventually, but the behaviour was concerning enough for me to not take my chances.

 

Oh well, even if not too heavily loaded, at least you got some extra time.    Does it sound any different now?  I guess with the 6L6 regulator, it probably doesn't have much effect as long as the rectifier was still producing more voltage than the regulated target voltage.

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13 minutes ago, aussievintage said:

Does it sound any different now?  I guess with the 6L6 regulator, it probably doesn't have much effect as long as the rectifier was still producing more voltage than the regulated target voltage.

Nope. It seems rectifiers either work, or they don't.

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2 minutes ago, Ittaku said:

Nope. It seems rectifiers either work, or they don't.

Well, as I was saying, you have a regulator after yours, so instead of the equipment working on a slightly reduced voltage as the rectifier loses emission with age, yours stays steady at the lower regulated voltage.  

 

I am running my preamps and even the 2A3 SET stright from unregulated filtered rectifier output (no regulators) and I have no idea how many hours are on them.  I just measure the HT whenever I have them on the bench - all is going well.  I did blow up one in the SET a few years back - replaced it with a secondhand one of unknown hours, and it's still going strong.

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1 minute ago, aussievintage said:

Well, as I was saying, you have a regulator after yours, so instead of the equipment working on a slightly reduced voltage as the rectifier loses emission with age, yours stays steady at the lower regulated voltage. 

Sure that makes sense. One of the potential advantages of a fully regulated PS.

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I should also add the rectifier went on powering the preamp up, as valves virtually always do. This is why I'm very particular about how many times I power cycle my devices and give myself arbitrary rules for how long to leave things on for if they're idle instead of cycling them.

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I got the Andrea panels. They look great with a nice velour finish. The lifestylestore couldn't tell me when and if they'd ever get them in white so I settled for grey.

 

IMG_20200206_162447.thumb.jpg.4af8e0e069acad4671015191c16b0175.jpg

 

Strangely though when I look at their construction from the back, ultimately they're just foam with a fabric cover and a light wooden frame. I'm not sure what I expected the fancy sound absorbing material was, but foam wasn't it...

 

IMG_20200206_162457.thumb.jpg.f8e62c7995e5d0a406e3a41b5f7c6cbe.jpg

Edited by Ittaku

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Con, you’re a talented man. The system looks amazing. Just went through most of this thread for the first time. I say most because there’s plenty of info there that just goes over my head! On a side note, will you be going to the Ninth on Feb 22? I’m beside myself with excitement to see and hear this performed again. Cheers, M

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2 hours ago, unclemack said:

Con, you’re a talented man. The system looks amazing. Just went through most of this thread for the first time. I say most because there’s plenty of info there that just goes over my head! On a side note, will you be going to the Ninth on Feb 22? I’m beside myself with excitement to see and hear this performed again. Cheers, M

Thanks! I'm going to the classic performance of the 9th towards the end of the year and thoroughly looking forward to it!

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On 08/02/2020 at 9:05 PM, Ittaku said:

Thanks! I'm going to the classic performance of the 9th towards the end of the year and thoroughly looking forward to it!

Excellent. What are the details of the performance you’re going to? Do you have a link? Cheers. M

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3000 hours on my power valves now which is the recommended time to replace them according to ARC. Tested them all again and they're all still testing fine. Once more the right side regulator tube was almost gone on the preamp power supply so I'm suspicious that there's something wrong there. I've emailed Mick to see what he thinks since he said they'd be good for 10,000 hours, but I'm only getting 1000 hrs out of the right side regulator. Fortunately they're not expensive valves so I just ordered a replacement. I keep wondering if the KT150s in the power amp will just remain well above specification but slowly go off in quality and distortion instead. I've never seen that happen before since they usually run hand in hand.

Edited by Ittaku

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39 minutes ago, Ittaku said:

I've emailed Mick to see what he thinks since he said they'd be good for 10,000 hours, but I'm only getting 1000 hrs out of the right side regulator. Fortunately they're not expensive valves so I just ordered a replacement.

He got back to me and said I'd need to check voltages with it running and the base open and valves in place. Given how cheap the valves are I think I'll pass since it's pretty dangerous dealing with very high voltages and currents. Maybe the next ones will last longer - I'm trying a different brand.

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I spent a while trying to figure out how to non-destructively hang the room treatment panels on the troublesome wall and with the help of my wife's suggestions (she used to be an engineer) we came up with this.

I used the round hooks at the top of this pack screwed into the back of the panels:

IMG_20200216_132619.thumb.jpg.88c5b923886f28a87e0fe95ba99abb2c.jpg

 

I put these non-destructive sticking hooks on the wall:

IMG_20200216_132610.thumb.jpg.72e7e1da7107211f28494e2432a0d257.jpg

 

Here are the hooks on the wall:

IMG_20200216_132727.thumb.jpg.f7d5d913af71184583b353a79c74881d.jpg

 

Here're the hooks on the back of the panels with twine used as a hanger wire:

IMG_20200216_132709.thumb.jpg.ca5caad43edd2bd862f9341eaeb9a8d5.jpg

 

And the final result with them on the wall looks like this:

MVIMG_20200216_132651.thumb.jpg.bb1a020af73c8372a16d5119c058622e.jpg

 

Yes it makes quite a substantial difference with a lot more focus in the top end especially (which is where the problem was.) Now to find a way to use the same treatment panels in a "mobile" form that allows me to stand them up on the side walls since there are no actual walls to stick them to. I was thinking of using a drying or clothes rack on wheels and mounting two panels side by side.

Edited by Ittaku

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Since I haven't had much luck with the life of the regulator valves I've been using, I figured I'd switch to a different one, and as I've had good success with Sovtek's rectifiers, I figured I'd try their 6L6WGXT (an improved 6L6WG). As I'm at 3000 hours on my valve counter it will be easy to keep track of how long these ones last for. They test fine, and work fine, but only time will tell. No, they don't sound any different... but then regulator tubes shouldn't affect audio quality unless there's something horribly wrong.

 

 

IMG_20200217_103655.thumb.jpg.2d68421a811b47a4f9607db1b44d1083.jpg

 

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I forgot to mention I've also since moved to a Matrix USB-SPDIF-2 for USB conversion, isolation, and de-jitter to the DSP. It allows me to use AES to the headphone DAC and coaxial and/or optical to my DSPeaker for the main hi-fi duties. So far so good, but no audible difference to the main system since it's so far back in the chain. Headphone system seems to breathe a bit better, sounds a bit more open and deglared, and the bass seems more fleshed out and impactful. Hard to know if that's due to jitter reduction (femtosecond clocks), USB isolation, or both. It was interesting to see measurements on this little gem and see that it actually had lower noise when powered via the USB instead of using a separate linear power supply with it. There is already excellent isolation in the power path from the USB, but potential for ground loops when using a separate power supply.

 

IMG_20200217_104730.thumb.jpg.7fa7feb542fe7f2cd547590a061ebaca.jpg

Edited by Ittaku

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10 minutes ago, Ittaku said:

as I've had good success with Sovtek's rectifiers, I figured I'd try their 6L6WGXT

I have had good success with Sovtek in tough usage applications - such as a very stressed pair of 6CA7s in a bass guitar amp where other cheaper valves ended up arcing over.

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I've updated my opening post yet again to more accurately reflect my current system. I guess even when I'm not making major changes, I'm still tweaking minor things.

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