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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 465

post #6961 of 6966
Quote:
Originally Posted by gibosi View Post
 

 

Given the price of a LD mk9, I personally don't think it would be worth it....

 

I have a 4-speaker system: two satellites and two subwoofers (that I haven't listened to in ages). Out of the preamp, I have an electronic crossover which in turn feeds two stereo power amps, one for the satellites and one for the subwoofers. The crossover point is 100 Hertz. Unless the crossover point is substantially much higher in your system, dedicating a preamp to handle a frequency range of 20 to 100 Hertz, or so, would be a real waste of money, and further, would make your system unnecessarily complicated with no discernible benefit. I strongly suspect that if you install 6AS7's or 6080's in your IV, the bass would likely be indistinguishable from that of a MK 9.

 

But anyway, as usual, my opinion is exactly worth the price you paid. :)

 

Cheers

 

Interesting setup. I was thinking of a crossover more in the range of 1,500 Hz, but not an absolute active filtered crossover. Relying more on the passive crossover within my bi-amped speaker.

 

I agree that modded Mk IVs likely sound identical to the Mk 9 with regards to bass, and probably 'fullness', which I see as coming from lower-mids. I'm going to try some 6SN7s first, but I still may do it.

 

Best,

 

G

post #6962 of 6966

Generally speaking, it is best to set the crossover point as low as possible. Middle C is about 262 Hertz. The top note on the piano is about 4000 Hertz. 1500 Hertz is roughly in the middle of what is generally considered to be the midrange. A crossover inevitably adds some distortion as you roll-off from one speaker driver to the other. And you may very likely be able to hear that transition at 1500 Hertz. Almost every instrument will be affected. At the very least, it is best to stay below the midrange.

 

Fundamentals are red, yellow are harmonics

 

 

900x900px-LL-a2b0f1c3_main_chart-610x677.jpeg 


Edited by gibosi - Yesterday at 9:07 pm
post #6963 of 6966

Hi MMMan,

 

"Output of the power tube IS directly influenced by the output of the driver tube. The power tube cannot recover detail that is not passed to it by the driver... so everything I have read on here suggests that different combinations tend to influence either the higher end or the lower end. Do any combinations do a fantastic job of both?"

 

I am not sure if I understand what you are saying here. IMHO different power tubes extract more detail and bass than others. As an example, the RCA 6AS7 bring out more micro details than the RCA 6080 tubes I have. In previous comparison tests, the different versions of the 6N6P variants (6N6P, 6N6P-i, 6N6P-IR and 6H30-DR) mainly differed in the bass punch delivery. In other words, using the same driver, all these power tubes will make the sound different, some in details and some in bass, and some in both. Other areas where there was a difference was quickness and timbre.

 

Perhaps some power tubes recover more detail from the driver tubes than others. I think I read about the GEC 6AS7 tubes that "they add an additional layer of detail to the sound." By way of analogy, a sensitive radio receiver would pick up more stations than one less sensitive. The signals are all there, but not every receiver is able to pick all of them up.

 

I do feel that the tube combination I am using now does a fantastic job of all the ranges, bass, mid and high. IMHO there is definitively a synergy between driver and power tubes. It appears to me that my power tubes are somewhat dark, and the driver tube somewhat bright, and the combination works out very well.

 

All of the above is based on my subjective listening impressions, and hopefully not influenced by any hype and preconceived notions.

post #6964 of 6966
Quote:
Originally Posted by hypnos1 View Post
 

Update on the 6HM5s (Yugoslavia?!)...

 

Despite the blinding flashes still on start-up(!) - but with no obvious ill-effects after 50+hrs - these have definitely knocked the RCA 6DT6As off their perch. Initial reservations have been totally kicked into touch. I have now become an avid fan of really wide and deep soundstage, even though I thought it at first a rather less "intimate" sound. I love the 'airiness' and clarity these babies are putting out. And the range and 'cleanliness' of treble notes, coupled with extra instrument separation is truly a revelation. This separation probably also explains my initial doubts over bass response - what I thought may be a negative, ie less perceived 'slam', I now realise may be down to a much more subtle reproduction of different TYPES of lower frequency...ie a nice spread, rather than 'bunched', which at first can seem less weighty.  Perhaps these tubes are not for heavy head-banging - unless you turn that knob right up! Then again, I am a firm believer that less is more as far as bass is concerned - there are so many fine, detailed things going on in a really well-recorded piece of music that it is bordering on the criminal to overpower them indiscriminately...just my personal thoughts, that is...But despite my ramblings, please don't get the wrong impression - bass is lovely and rich from these tubes. Give 'em a try! And the beauty of these also is they are just "plug 'n play" (EF95).

 

Happy rolling.


i just tried them and i could say that i totally agree with you...

post #6965 of 6966
Quote:
Originally Posted by gibosi View Post

Generally speaking, it is best to set the crossover point as low as possible. Middle C is about 262 Hertz. The top note on the piano is about 4000 Hertz. 1500 Hertz is roughly in the middle of what is generally considered to be the midrange. A crossover inevitably adds some distortion as you roll-off from one speaker driver to the other. And you may very likely be able to hear that transition at 1500 Hertz. Almost every instrument will be affected. At the very least, it is best to stay below the midrange.

Fundamentals are red, yellow are harmonics

Snip....snip...

Hi Gibosi,

Cool chart... Thank you.

I think the internal crossover for my speakers is 1500hz. Since I won't use an external active crossover, I will be crossing over at 1500hz based on the speakers design. Perhaps later I will get speakers than can cut out the internal crossover and I can input directly to the driver, but that's something for the future...

Best,

G
post #6966 of 6966
Quote:
Originally Posted by mordy View Post

Hi MMMan,

"Output of the power tube IS directly influenced by the output of the driver tube. The power tube cannot recover detail that is not passed to it by the driver... so everything I have read on here suggests that different combinations tend to influence either the higher end or the lower end. Do any combinations do a fantastic job of both?
"


I am not sure if I understand what you are saying here. IMHO different power tubes extract more detail and bass than others. As an example, the RCA 6AS7 bring out more micro details than the RCA 6080 tubes I have. In previous comparison tests, the different versions of the 6N6P variants (6N6P, 6N6P-i, 6N6P-IR and 6H30-DR) mainly differed in the bass punch delivery. In other words, using the same driver, all these power tubes will make the sound different, some in details and some in bass, and some in both. Other areas where there was a difference was quickness and timbre.

Perhaps some power tubes recover more detail from the driver tubes than others. I think I read about the GEC 6AS7 tubes that "they add an additional layer of detail to the sound." By way of analogy, a sensitive radio receiver would pick up more stations than one less sensitive. The signals are all there, but not every receiver is able to pick all of them up.

I do feel that the tube combination I am using now does a fantastic job of all the ranges, bass, mid and high. IMHO there is definitively a synergy between driver and power tubes. It appears to me that my power tubes are somewhat dark, and the driver tube somewhat bright, and the combination works out very well.

All of the above is based on my subjective listening impressions, and hopefully not influenced by any hype and preconceived notions.

Hi Mordy,

Sorry I didn't describe it very well. All I am suggesting is that perhaps one set of tubes optimised for high end detail plus another set of tubes optimised for very well defined mids and bass may perform better than a single set.

A tube is simply a signal processor with an emphasis on amplification. All are imperfect in the way they amplify our audio signals, but some of these imperfections sound nice. Other imperfections lead to information loss. Some tubes lose information in the high end and some lose information in the low end. We tend to compensate by matching a bright driver with a Bassy power tube, or vice versa. I want to see what happens if we match a bright driver with a bright power tube then compensate with a second system that matches a mid- oriented driver with a solid bass power tube. Just out of interest. If nothing good happens, I find the best overall tubes for the mk 9 and move the mv IV to my man-cave. Win-win...

But, I have some 6sn7s on the way.... And maybe they will convince me I don't need to try bi-preamping.

Best,

G
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