NOSValves
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Posts posted by NOSValves
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On 4/10/2021 at 7:29 PM, sootshe said:
Very interesting how our thoughts differ in sound comparison.
I bought a set of Beymas from Greg based on his test results.....when I hooked them up I only listened to them for about 5 minutes before advertising them for sale.
To my ears they were extremely brash, rough & unrefined. To make sure I wasn't making a mistake, I compared them to a pair of JBL 2404 "baby cheeks" & then I realised I wasn't wrong, as the JBL's were in a different league altogether. Maybe there was a fault with the ones I had?
I couldn't be happier with my current DE-10's with the timber flare.
That's because they were most likely playing 4 to 6 db too hot! Almost all the aftermarket tweeters folks use are too efficient for a Klipsch speaker. You need to invest in ALK tweeter attenuator at the very least. Same goes for changing mid horn, mid driver or both.
If running the DE-10 it's too hot with a Stock Klipsch crossover too! About 3 db in my opinion.
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The discontinued Ruby from Doug was identical to the Penta Lab which is also impossible to find. This tube used to be the same I'd write them ask before buying https://www.thetubestore.com/preferred-series-kt88. Those Penta triple getters were my favorites for many years. The Ruby STR you have is the same as the Valve Art or Chinese KT88-98 made on the same factory line as the Penta's it's a decent tube and has always been my #2 and the tube I supply with amps.
The thing is I think you'd be ahead of the game to play with the 12AX7 and 12AU7 slot to rid yourself of the fatigue or possibly look the the source or source material. Changing output tubesa is going to have nearly the least effect out of the tubes to fine tube. The 5AR4 will have zero musical effect unless it wore out or defective.
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Hey guys On The Fly is just fine the only thing is you'll most likely get a electric spark sound out of your speakers. It's not spark going to your speakers its just the amplifier reproducing the sound of the connection change.
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15 hours ago, Allan Songer said:
Suddenly it’s 2006
2006 are we having fun around here again....watch out they'll lock the thread 😁😜
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23 hours ago, Allan Songer said:
I haven’t changed my main system in 13 years. Nearly 30 if you don’t count the CD player or the addition of a second tonearm to my table.
Wow Allan great to see you posting! Hope you and yours are doing well! You still styling with the Mac gear?
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On 2/27/2020 at 3:45 PM, tube fanatic said:
Joe, given how easy it is to manually bias, and how infrequently it needs to be done, are you sure you want to make such a substantial investment?
Maynard
exactly what I said
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On 2/27/2020 at 9:36 AM, Jeffrey D. Medwin said:
Hi Joe !!
You realize, spending money for the auto bias mod will not change the sound of the amp, for the better, one iota??
Proper mods, spent on upgrading specific parts, or power supply enhancements, will .
Is that amp and circuit ultimately worth modding, VS, say, maybe a new pair of QuickSilver Mid-Monos or a Carver Crimson 275 ???
Jeff
Pretty much what I said......of course the guy selling the product begs to differ.
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Joe,
If you can take some detailed photos top, bottom and I'll take a peak and see if I can figure something out for you. Be patient my available time is very limited these days..
I agree if he did both amps parts would match in both amps
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Joe I used Curcio stuff many years ago but my memory is to foggy on it to help you. Contact Joe I'm sure he'll help you out.
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John,
Yup Heyboer does a nice job on many vintage transformer replacements. Most of the Scott they worked with me to iron out the specs many years ago.
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Dave order them from www.tubesandmore.com they do a decent matching with Ampex tube tester.
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The Valve Art is a basic Shuguang factory made KT88-98 with Valve Art QC testing. The Ruby KT88-STR is the exact same tube with Ruby QC testing. It is also sold as the Shuguang KT88-98
It is a nice sounding KT88 for reasonable entry cost
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20 hours ago, rplace said:
Is it normal to need to need to turn the bias screw A LOT when changing rectifier and output tubes? My KT88s were right at .55. After swapping things out my EL34 were reading .02 to .08. I probably had to turn the pots clockwise (increasing) 10 or 12 revolutions to get them to .40. Figuring I'll start out on the low side. Initial impression is that my HF sections of the 2-way set up are way overpowering the bass bins which makes me think I've actually dialed them up a lot. I can knock the HF back or increase the LF to balance them out but since I turned the bias pots up so much It makes me wonder if I'm doing something wrong. In case it is not obvious I have separate amps for HF and LF. The LF system as a whole did not changes in any way.
So increasing the value say .55 to .65 actually increases the output in a KT88 set up? I agree I don't care about output as I typically listen on the quiet side. I want them to be "right" whatever right is.
It seems odd to me that I would have gone from a higher output tube (KT88) to a lower output tube (EL34) and the bias went from .55 to .40 and the amp made my HF section a lot louder. I had to make a 7dB change to get the HF/LF somewhat balanced back out. I'll do some actual measurements next. Does this pass the sniff test, am I in the ball park of doing things correctly? Am I overthinking this and I should just turn the pots as necessary to get the readings I want and move on?
Rich,
What you describe going from KT88 to EL34 is totally normal. Now when/if switch back realize the reverse is going to be true and you should adjust the controls about 8 full turns counter clockwise before you fire the amps back up with KT88 type tube again. Each output tube type can take a hugely different applied negative voltage applied to the tube to achieve the proper bias current. Realize when you adjust the bias screw your not adjusting the actual voltage you read at the test point you are adjusting a voltage applied to the control grid of the tube that causes the test point voltage to change.
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Rich,
Not ignoring you I did reply but promptly received a kick back notice of a permanent fatal delivery error. I believe your mail server has my mail server blocked. Here is what I* replied. I also tried to send you a current manual which should/could be the same as the one you have.
Rich,
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX first line X out because it was personal in nature.
Glad you wrote me about bias confusion. Always refer to the manual that came with your amps. The folks mentioning .70 bias setting have some of the amps manufactured in the early to mid-2000’s and have not had them updated. I believe your manual should give you bias setting for EL34’s. If not attached you find one that does.
I will caution you that if using modern production EL34’s error to the cool side first than check the large plate structure inside the tube for red glow. Many modern production EL34’s are pretty weak. Also realize I have never had someone report back they preferred EL34’s in a VRD which makes total sense since it runs them too darn hard. You could help things out a little by running them with a 5U4 rectifier tubes which will lower the voltages in the amp a little but in the end the amps are still primarily designed to run the KT88 family of tubes.
Thanks Craig Ostby
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mix and match pairs? Not sure what you mean?
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It will work just fine. Those are re-branded most likely Mullard made tubes. Sylvania never made tubes in England. Either way they should be really good tubes. Do realize the 299B is not a plug and play amplifier when it comes to the output tubes they do require proper biasing when installed and periodically after that.
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Definition of scary
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On 8/4/2019 at 10:05 AM, Deang said:
In that first thread, I went so far off the rails that Amy kept deleting my posts so she wouldn't have to ban me.
I wish she would have just banned you
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Neal got it thanks I also got an email. Not sure why I can't get the forum to send me thread notices. See you in the couple weeks!
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So August 10th is the final date? For some reason I'm getting no notices from the forum software... so if someone could update me of changes via email if you think of it that would be great. My life is a whirl wind so I just never log in here as much as I used too. I do plan to come to this get together. email craigATnosvalvesDOTcom
I'll also need the address.
Thanks Craig
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On 7/3/2019 at 7:33 PM, Sancho Panza said:
ONLY Kid Rock song I like.
Hmmm the area he sings about in the song is right where I live now and grew up... he's still seen hanging in the bars around here now and then. The area really hasn't changed all that much wish I could say the same thing about southeast Michigan!@
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As long as I have some notice I can usually make a day or two get away happen. This sounds like fun! Wish I had a way to turn on notices for just one thread... heck maybe there is.
I'll have a 3 hour drive to get down there....
I found the button for notifications. Not sure what it will notify me of...
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As long as I have some notice I can usually make a day or two get away happen. This sounds like fun! Wish I had a way to turn on notices for just one thread... heck maybe there is.
I'll have a 3 hour drive to get down there....
I found the button for notifications. Not sure what it will notify me of...
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Thoughts on using Beyma CP25 tweeters
in 2-Channel Home Audio
Posted
Thanks! Better than it has been in a long time. I've had a pretty horrible couple years. long story....