mark1101 Posted November 18, 2003 Share Posted November 18, 2003 The subject of the 12db high and low end filters in the Scott 299 and 299B seems to have fizzled out. I have been waiting to see what was found. Supposedly removing these filters improved the sound quality and range, and cleared up scope trace distortions on the high and low end. My question is to Craig, Mark, and anyone else on if they know if there is a significant audible improvement with the filters removed. Ryan, we already heard you say there was, "so 299s and 299Bs sucked" without this mod. In building old super het radios and trying to align them, I have seen clearly that the best scope trace is hardly ever the best sound to your ears. Tuning for the ears always seems to detune the scope pictures a little bit. So what's the answer? Should the filters be removed for better sound, or is this a waste of time and money? Craig, did you ever complete your tests on this issue? I'm not as interested in scope pictures as in audible improvements. I would bet the scope pictures do improve, but can you hear it????? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 18, 2003 Share Posted November 18, 2003 Mark, Just have Patience this is not a simple thing to do as some have suggested it is 3/4 done on my own 222B which took major redesign. I have to shelve it to get to work on peoples gear have to pay the bills you know ! When you hear what all has to be done to get it right you will decide as I originally stated its not worth the cost unless your good enough to do it yourself and find this type of work fun not to mention have the test equipment to do it. Craig Quote Link to comment Share on other sites More sharing options...
mark1101 Posted November 18, 2003 Author Share Posted November 18, 2003 Craig, Glad to hear you are looking at it. I know you are busy. Maybe some others on this forum can comment if they know the answer. Surely these filters existed on other vintage amps as well for the same reasons of taming poor phonograph signals from back in the day. Anyhow the Scotts are playing pefectly as usual. Just wondering if they could be further improved (easily). It sounds like this could be a hassle of a mod. I'd be interested in seeing the mod on a schematic when you get the time. Keep the solder flowin' Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 18, 2003 Share Posted November 18, 2003 improved (easily). Absolutely not easy !! Every model will be slightly different and schematics will not be offered its just not that simple trust me on this. I don't believe for a second Ryan has ever done this to a Scott amp if he has I would love to hear just how he accomplished it easily because it can not be done easy and get any real benefit in fact its the exact opposite ! Craig Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted November 18, 2003 Share Posted November 18, 2003 Craig, Thanks for looking into that. One thing I and maybe others appreciate about your approach is the no-BS Practicality aspect. This is called Pragmatism and it makes sense to me. C&S Quote Link to comment Share on other sites More sharing options...
garymd Posted November 18, 2003 Share Posted November 18, 2003 Craig, If you say it's a PITA and doesn't help, I certainly believe you. Thanks for you efforts! Where's Ryan? I'd like to hear his response to your findings after all the work you just put into this. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 18, 2003 Share Posted November 18, 2003 Well I'm not going to go to the extent of saying it isn't going to do any good. What I'm saying is its not a affordable option for me to offer. The entire amp is made to run with these filters which are throughout the amp actually and taking them out means you have to just keep going all the way thru the circuit adjusting and redesigning to get the gain , feedback and additional filters working right now that you bypassed the one original filter you wanted out of there its just not that simple. We have it pretty darn close now but time is my issue to finish it so it will have to be comeplted later. Its like pulling the bottom beer can from a stack you may intend for just the one to move but in the end they all come down. Craig Quote Link to comment Share on other sites More sharing options...
Deang Posted November 18, 2003 Share Posted November 18, 2003 Yes, I own a Scott integrated amp, restored, tweaked, highly modifed, and completely redesigned by NOSvalves. Sounds great -- and it only cost me $2000. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted November 18, 2003 Author Share Posted November 18, 2003 Craig, If that's the case, then don't bother. I don't think I'd want that much untested tinkering done anyhow. Sounds like an experiment. Both my amps are perfect as is. I use them both almost everyday. Ryan made it sound like an easy mod to get even better sound. Well who wouldn't be interested in that? Like if we weren't having this done, the amp was inferior. That's how I took it. I need to hear a 299D. I would know instantly if it was any better. The fact is that Scott kept evolving their designs so quickly, if each progressive design wasn't an improvement, something would be wrong. I would expect the newest amps to have advantages. So Ryan does have a point. At least you are taking the time to investigate and understand the true performance that can be achieved. I can appreciate that. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 18, 2003 Share Posted November 18, 2003 "I don't think I'd want that much untested tinkering done anyhow." If Craig's doing it to one of his amps, I can tell you the words "untested" and "tinkering" are not applicable. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted November 18, 2003 Author Share Posted November 18, 2003 I work in electronic controls development. We require thousands of hours of field data on hardware changes before a new design is released, and that's really not that much when put into perspective. It's all relative. I know Craig is an excellent tech. But he's experimenting on this one. We all know he'll get it right. It may be something awesome once complete. We don't know yet. But until it's been run for a few hundred hours with no ill effects, to me that's untested. I'll venture to say that due to tolerances, it takes several amps to verify that all the circuits remain robust and have not had their longevity compromised. Again, it simply goes back to Ryan making this mod sound like you clipped a cap and resistor and got a major improvement. I'm sorry to have contributed to sending Craig on this odyssey. I didn't think it was a snowball effect type of change with so much work involved. And you're right, tinkering was the wrong word. Quote Link to comment Share on other sites More sharing options...
dodger Posted November 18, 2003 Share Posted November 18, 2003 ---------------- On 11/18/2003 3:47:34 PM DeanG wrote: Yes, I own a Scott integrated amp, restored, tweaked, highly modifed, and completely redesigned by NOSvalves. Sounds great -- and it only cost me $2000. http://forums.klipsch.com/idealbb/images/smilies/9.gif"> ---------------- Dean: You are my pal, you found that website for me (thank you if I forfot to before - it was very helpful.) But I have to ask - is that including the cost of cleaning the chassis> ? Let me know if you start doing it. Win dodger Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 18, 2003 Share Posted November 18, 2003 Mark, if each progressive design wasn't an improvement, something would be wrong. I would expect the newest amps to have advantages This is where I differ completely from some others. I believe they kept throwing more bells and whistles at them and to some this may seem great. To me and my ears its a detriment to the sound. You have to look at the era as it happened. They were many things at play here. The more watts war ! The more bells and whistle wars primarily with Scott's #1 competitor Fisher. I think with a little research you will find that Fisher most sought after designs are of the early stages of stereo Hi Fi also. The same can be said for EICO for the most part. The SS brigade coming in and grabbing a major chuck of the market The fact that Scott original design engineer and HH Scott himself were both I bet both tired and ready to retire ! Which they both did after SS designs won over the market. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 18, 2003 Share Posted November 18, 2003 One thing about untried and untested. Really when it comes to tube audio its all been tested, tried and true. Another thing that should be absolutely clear without Mark Deneen helping me on something this drastic I would never even try it !! Mark is a absolute wonder at circuit design and trouble shooting " A True Tube Audio Engineer " not just someone that can talk the talk . I'm just a guy that loves to learn and does not get discouraged easily I believe this is why Mark keeps on with his generous help ! Craig Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted November 18, 2003 Share Posted November 18, 2003 Vintage is vintage. Maybe there is something to be said for bringing these units up to date by just replacing the old parts with new ones and thus experiencing what they were meant to be in the first place. It is certainly easier as a DIY thing for those of us with maybe just soldering skills and no scope yet. When you want a bias circuit added to your Scott etc. then its time to contact Craig. C&S Quote Link to comment Share on other sites More sharing options...
Parrot Posted November 19, 2003 Share Posted November 19, 2003 Ryan, I'm curious as to what filters you found you could easily remove to make an improvement. According to Craig's analysis, anything removed or altered requires adjustment elsewhere, which requires adjustment elsewhere, and so on down the line. If you could give some detailed specifics, it would be helpful. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 19, 2003 Share Posted November 19, 2003 Neat info. Thanks. You can relax a little though, I think Craig was just surmising about the retirement aspect, and heck -- they probably were tired! Now, the "watts war" thing -- I think that started in the early 1900's! It was about "more power" from the very beginning, and didn't stop until it got to Kelly's living room. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 19, 2003 Share Posted November 19, 2003 Well Ryan you did a good portion of the work. The 222D filter for the most part are Identical except for some values. But you missed the biggest filter in the amp ! Check a sqaure wave as it enter the amp and then again as it enters pin 2 of V2A or V102A you will see a mass change to the wave form. Trace the circuit back and you will find C10, R15 for V2A and C110, R115 for V102A and bypass these and see what happens ! Then start adjusting the rest of the circuit ! Also give a look at the signal entering the phase splitter and then at the 1uf cap to the output tubes again with Square wave. Craig Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 19, 2003 Share Posted November 19, 2003 Thank you Mdenneen. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 19, 2003 Share Posted November 19, 2003 Guy, Once again you are wrong I found that filter !! I'm sure Mark would be more than happy to confirm this. Without a amp on the bench its pretty hard to track this stuff down long distance for Mark or anyone for that matter ! Visualizing all the switches and what travels where with the switch in this or that position without the amp on your bench. Craig Quote Link to comment Share on other sites More sharing options...
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