trvale Posted November 9, 2002 Share Posted November 9, 2002 Well... I was looking to buy my first tube system as kind of an experiment. I obviously didn't want to spend thousands of dollars, so vintage was the way to go. I went searching ebay for some Scotts (222c, 299, etc.) I just didn't like the idea of having to restore these machines so I could use them for everyday use. Just seemed like these would turn into a money pit in order to keep them running. My only other option was a kit. There aren't too many to choose from today in my price range. I found some 5 watt/ch kits and a 8 watt/ch kit. Being the impulse buyer that I am, I immediately purchased the 8 watt kit made by k-5 electronics. It uses 11MS8 tubes in push-pull config. Is 8 watts enough for the SB-1's that are 92dB efficient? If not is there anything I can do to this kit to produce more power? As this is my first venture into tube amplification, I do not yet have an understanding of what actually determines the output wattage. Is the number of tubes important? Can I double the amount of tubes and get double the wattage? I am sorry if these are stupid questions, but this is hopefully a learning experience, so I can go on to build a higher quality amp later. Quote Link to comment Share on other sites More sharing options...
trvale Posted November 9, 2002 Author Share Posted November 9, 2002 Oh yeah I am also using a powered 10" Velo sub, so hopefully that will help with some of the power requirements. Quote Link to comment Share on other sites More sharing options...
JohnA Posted November 10, 2002 Share Posted November 10, 2002 It depends entirely on how and what you listen to. 8 watts into 92 dB speakers is 101 dB peak. That's not that loud for peaks. You can expect average levels to be 10 to 20 dB below peak. Quote Link to comment Share on other sites More sharing options...
prodj101 Posted November 10, 2002 Share Posted November 10, 2002 8 watts is enough for quite listening levels. I get my music up to 105 db often, so it wouldn't be enough. than again, I also have a 105 watt amp per channel. also, if the sub could handle the lower mid bass stuff, you could turn down the bass on the mains to the lowest wwhich would free up alot of power for the amp to drive them with. Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted November 11, 2002 Share Posted November 11, 2002 There is a member on this board (NOS440) that will restore your Scott 299 for free (you pay for all parts and shipping to/from). He has performed many restorations and knows his stuff about these units. Mine sounds incredible for the $270 I have invested in it ($125 purchase price and another $150 to Craig). He replaced most of the caps, resistors and tubes for this price. It is almost dead quiet and you won't find a better phono stage for anywhere near this kind of money. Also, it is 17 - 20 watts, and pushes my La Scala's to 105db with no problems (with plenty to spare). You will not find anything new that even approaches this kind of sonic bliss for under $300 imho... Mike Quote Link to comment Share on other sites More sharing options...
JCturboT Posted November 11, 2002 Share Posted November 11, 2002 Mike, Don't know if Craig will still do this labor for free as he is getting his fair share of buisness just from this Forum alone. I had him go completely through my LK-48 and it was several hundred dollars worth of parts & labor. I really don't think you could buy something new now-a-days that will come anywhere close to this performance for this amount of money. Jeff PS: still waiting on your AudioQuest Slate review Quote Link to comment Share on other sites More sharing options...
artto Posted November 30, 2002 Share Posted November 30, 2002 To answer your 4 questions quickly.......IMHO No No No and No As John mentioned above it depends on what you listen to & how loud & under what kind of conditions & 8 watts driving a speaker that has an efficiency rating of 92Db/watt/meter (aprox 1 yard or 3 feet) will produce 101Db at a distance of 1 meter. Every 3Db represents a doubling (or halving as the case may be) of amplifier power. For something to actually sound twice as loud to the ear requires a 10Db increase in sound pressure level. Presumably you have 2 speakers & an amp that is putting out 8 watts per channel. That would give you a total power output of 16 watts into the 2 speakers. Therefore, your total output from the speakers with the available power would be 104Db. Sound typically decays at a rate inversely proportional to the square of the distance, which is another way of saying that every doubling of the distance decreases the sound pressure level by 3Db. In a reverberant sound field, such as a closed room, the fall off (decay) in sound pressure level typically does not decrease as much beyond 12 feet or so. So if your speakers and amplifier can produce 104Db at 1 meter (I'm going to round off 1 meter to 3 feet), at a distance of 6 feet, the sound pressure level would be down about 3Db (yielding total system output of about 101Db) , and down an additional 3Db at 12 feet(yielding total system output of about 98Db). Even in live Classical music, peak sound pressure levels can easily reach 110Db or louder. If you're new to electronics, no, YOU are probably not capable of making changes to the amp to make it produce more power. There is more to it than just the tubes, or the number of tubes. Your subwoofer should be able to take some of the load off the main speakers and amplifiers if it has its own power amplifier. Quote Link to comment Share on other sites More sharing options...
trvale Posted December 1, 2002 Author Share Posted December 1, 2002 I am finally able to answer my own question. After I recieved the kit I was able to put it together in a few hours, very simple. I turned the thing on and was blown away at how this amp sounded. I wasn't expecting too much of a difference from my Onkyo TX-DS595, but I was wrong. The sound is much more warm and natural, and the bass response is wonderful. Now as far as the power output, well its more than enough for me. However what I consider enough is nowere near 110dB or higher. I don't have a sound meter but I would guess the loudest I listen to is less than 100dB. The only time I would ever listen to anything that loud would be watching a movie, and then I would use the Onkyo for surround sound. As far as upgrading the amp to produce more power, I have learned that it would require new transformers with different secodary values. The the capacitors, resistors, and tubes would have to be able to handle the new power output. This is too much work for something I am happy with right now. Maybe later when I get bored with this amp. Right now I still need to build a case. I completely recomend tubes to anyone who loves music. And for those of us who are poor, the K12-M from S5 Electronics is an inexpensive way to learn about and experience tube amps. Quote Link to comment Share on other sites More sharing options...
akshobhyavajra Posted December 3, 2002 Share Posted December 3, 2002 FWIW - I am successfully using a 1.8 watt SET amp with Reference 3As (92 db; 8 ohms; no xover) in a 16 x 12 x 8 dedicated room. I listen to opera, classical and jazz at what I consider moderate and above moderate levels without clipping. Depending on room size, associated equipment, topology 8 watts can certainly be sufficient. Regards, ~Michael~ Quote Link to comment Share on other sites More sharing options...
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