DrWho Posted May 9, 2007 Share Posted May 9, 2007 I've been reading up on the effects of output impedance for amplifiers lately and there seems to be a trend of tubes tending towards a higher output impedance. The end effect of an amp with high output impedance is one of the frequency response following the impedance response of the speaker. We all know that with the onset of old age, comes a decrease in our ability to hear high frequencies. Since most speakers usually exhibit rising output impedance as frequency goes up (especially tweeters), I have to wonder if perhaps all the rage about tubes with the more seasoned folk on the forum is that the tonal balance is shifted up a bit? It would definitely explain all the observations about clarity, detail, imaging, whatever that can arguably be associated with high frequency extension. And then to take it a step further - I have to wonder if the variances in tonal balance between all the different amps people are swapping out has more to do with the output impedance of the amplifier more than it does with the actually topology. Anyone happen to have any measurements of the output impedance of their amplifiers? I think it would be interesting to try to correlate trends between output impedance, room acoustics, listening styles, and all the fanciful audiphile descriptions for the various amps... Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted May 9, 2007 Share Posted May 9, 2007 Seasoned ...?? ...Oh ... I was thinkin' seasoned .. Tube's while your thinking ..... Maron .... [] well, Crown's typically have very low output impedance, due to the large number of output devices.. So, no .. I haven't noticed that effect... Quote Link to comment Share on other sites More sharing options...
dkp Posted May 9, 2007 Share Posted May 9, 2007 This should be an interesting thread... Quote Link to comment Share on other sites More sharing options...
Deang Posted May 9, 2007 Share Posted May 9, 2007 Though a primary factor, differences in output impedance is just one of the factors that accounts for why tube amps sound different than most solid state (and from each other). However, I do agree that a lot of what people are hearing is a result of it -- especially because of the wild swings in impedance inherent with most of the Klipsch networks. No feedback amplifiers with high output impedances will sound different from speaker to speaker. http://www.transcendentsound.com/amplifier_output_impedance.htm Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 well, Crown's typically have very low output impedance, due to the large number of output devices.. So, no .. I haven't noticed that effect... lol [Y] Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 This should be an interesting thread...Hopefully. Things have been awfully boring on the forum lately and I'll be done with finals in a few hours - just chillaxing a bit before I go own up the matrix. Stupid robots. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 differences in output impedance is just one of the factors that accounts for why tube amps sound different than most solid state (and from each other). Apart from distortion characteristics (since those have been beat to death), what are the other factors? Quote Link to comment Share on other sites More sharing options...
Deang Posted May 9, 2007 Share Posted May 9, 2007 Apart from distortion characteristics (since those have been beat to death), what are the other factors? Slew rate. Quote Link to comment Share on other sites More sharing options...
dodger Posted May 9, 2007 Share Posted May 9, 2007 Greetings: I have noticed a slight and sometimes not so slight difference in tonal balance, depending on the brand. Win (dodger) Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 9, 2007 Share Posted May 9, 2007 I've been reading up on the effects of output impedance for amplifiers lately and there seems to be a trend of tubes tending towards a higher output impedance. The end effect of an amp with high output impedance is one of the frequency response following the impedance response of the speaker. We all know that with the onset of old age, comes a decrease in our ability to hear high frequencies. Since most speakers usually exhibit rising output impedance as frequency goes up (especially tweeters), I have to wonder if perhaps all the rage about tubes with the more seasoned folk on the forum is that the tonal balance is shifted up a bit? It would definitely explain all the observations about clarity, detail, imaging, whatever that can arguably be associated with high frequency extension. And then to take it a step further - I have to wonder if the variances in tonal balance between all the different amps people are swapping out has more to do with the output impedance of the amplifier more than it does with the actually topology. Anyone happen to have any measurements of the output impedance of their amplifiers? I think it would be interesting to try to correlate trends between output impedance, room acoustics, listening styles, and all the fanciful audiphile descriptions for the various amps... Well nice try..... your just never going to get it [] Now explain why SS is described by Tube users on many cases as shrill, bright and fatigueing........... I have customers loving tube gear of every single age as low as in the teens on up in the 70's. My daughter and son along with countless numbers of friends in the teen years could easily pick out the absolute superiority of tubes versus SS at the age of 13 or 14 when on got head over heals into tube gear. Heck my daughter had a party over at her house a few weeks back and asked me to setup my tube gear with the Chorus's that she normally uses with SS so she can have a remote. I asked her why she replied......."Well Dad I want my friends to enjoy the music".... LMAO!!!!!! Craig Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 Apart from distortion characteristics (since those have been beat to death), what are the other factors? Slew rate. Thanks - sounds like I've got a bit more reading to do. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 your just never going to get it [] Now explain why SS is described by Tube users on many cases as shrill, bright and fatigueing........... lol [] You're right - I'm never going to get it until someone starts posting quantifiable data instead of all these fancy descriptors subjective to psychoacoustics [] Btw, I think it's safe to argue that more than just old people prefer a tipped up response. It's that whole smiley-face looking graphic EQ effect. It works especially well at lower listening levels. [] Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted May 9, 2007 Share Posted May 9, 2007 Btw, I think it's safe to argue that more than just old people prefer a tipped up response. It's that whole smiley-face looking graphic EQ effect. [+o(] Quote Link to comment Share on other sites More sharing options...
ZAKO Posted May 9, 2007 Share Posted May 9, 2007 At my age i do not prefer a tipped up response....Thats a stupid assumption...I do not prefer SS or tubes....But i mostly prefer a live orchestra sitting about 8th row with out amplified instruments....Something all you young deaf music lovers need to do. At least once a week to calibrate your ears. Now dont hiss me off i,m watching the Simpsons. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 I think I'd like to see the measurements that the table was derived from. Especially the raw plots of the distortion measurements. And then I would also like to see the output impedances and compare them against the impedance of the speaker the amps were intended to drive. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 9, 2007 Author Share Posted May 9, 2007 At my age i do not prefer a tipped up response....Thats a stupid assumption...I do not prefer SS or tubes....But i mostly prefer a live orchestra sitting about 8th row with out amplified instruments....Something all you young deaf music lovers need to do. At least once a week to calibrate your ears. Now dont hiss me off i,m watching the Simpsons. How bout twice a week with unamplified and twice a week with amplified? And then maybe a day or two listening at home inbetween? Quote Link to comment Share on other sites More sharing options...
JJkizak Posted May 9, 2007 Share Posted May 9, 2007 Oh well, in 1985 when I switched from tubes to SS I eliminated high-freq noise, rumble, muddy bass, hum, and feedback at high volume levels. I don't think I want to spend thousands of dollars to go backwards for some psuedo musical trait that 99.99999% of the population cannot hear. JJK Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted May 9, 2007 Share Posted May 9, 2007 ) I think Amp 2 is better than Amp 1. What do you think? don't know 'bout you ... But I can't hear spec's .....[] sounds like it would be hard to tell 2 decent amp's of quality apart, anyways [8-)] Quote Link to comment Share on other sites More sharing options...
garymd Posted May 9, 2007 Share Posted May 9, 2007 That is the most ridiculous theory I've ever heard. You never cease to amaze me Mike. Quote Link to comment Share on other sites More sharing options...
seti Posted May 9, 2007 Share Posted May 9, 2007 Horns love tubes and I don't give a dam why : ) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.