the speakers im going with is the klipsch rf-7... they are 102 db. now... what amp should i go with?
I've got a pair of Mark III. I hope they perform a little better than stock, as I've more or less completely rebuilt them. They've got new driver boards, new cap boards, and new bias supplies in them. I have a friend with some fairly high-end, high powered solid state stuff (Bryston 9B-ST driving a set of Thiel CS2.4). He seems to prefer my Mark III over most of my other amps. On the other hand, I find I generally get more enjoyment out of my low powered single ended amps. I've got a 6B4G amp that's only good for about 3 watts, and a Tubelab Simple SE that might make 4 or 5. You wanna buy a pair of Mark III? 😉
It is very difficult to describe how an amp sounds, especially using terms that might allow someone else to decide whether or not they will like it. It would be ideal if there were a place where you can try out a couple different amps. Otherwise, be prepared to spend a lot of time (and money!) going through many different designs until you find the one you like.
The advice regarding speakers is good, too. There's a lot to do with finding the right combination between amp and speakers.
http://i69.photobucket.com/albums/i43/Ty_Bower/Mark III/P1100876.jpg
http://i69.photobucket.com/albums/i43/Ty_Bower/Mark III/P1100717.jpg
SS,
Per Paul Joppa's 102 dB. rule, the Klipsch RF-7s will be OK, most of the time, with (sic) 1 WPC. Your ears will bleed if you cranked 35 WPC up. Yes, even somebody, like you, who favors "head banger" stuff will run from the room.
While hardly inexpensive at $2200/pair, the RF-7s may be a good value. You can go for a nice amp, whose power O/P is modest. O/P trafo costs make lower powered tubed amps much more affordable than amps whose power O/P is substantial.
You asked about bass performance. Klipsch claims 3 dB. down at 32 Hz. That's quite adequate for a kick drum, but comes up a tad short for a double bass. The lowest note the huge fiddle can play is 31 Hz. If you get into pipe organ music, down the road, you can add a sub. Otherwise, I think the RF-7s will do nicely, if you can afford 'em.
AFAIK, no poster has yet addressed the signal source and preamp issues. Is a CDP the only signal source? Has any thought been given to a preamp?
Given all of the above, I will immodestly suggest that an "El Cheapo" be constructed using Dynaclone Z565 O/P trafos. "El Cheapo" is a challenging, but quite doable, 1st project. 6 WPC in triode mode and 12 WPC in ultralinear (UL) mode will be quite adequate in combination with the high efficiency Klipsch speakers. A separate preamp is not needed, if a CDP is the signal source. Even employing good O/P "iron" and some premium parts will not raise costs above $500. 😀 If "El Cheapo" interests you, read its LENGTHY saga here.
Per Paul Joppa's 102 dB. rule, the Klipsch RF-7s will be OK, most of the time, with (sic) 1 WPC. Your ears will bleed if you cranked 35 WPC up. Yes, even somebody, like you, who favors "head banger" stuff will run from the room.
While hardly inexpensive at $2200/pair, the RF-7s may be a good value. You can go for a nice amp, whose power O/P is modest. O/P trafo costs make lower powered tubed amps much more affordable than amps whose power O/P is substantial.
You asked about bass performance. Klipsch claims 3 dB. down at 32 Hz. That's quite adequate for a kick drum, but comes up a tad short for a double bass. The lowest note the huge fiddle can play is 31 Hz. If you get into pipe organ music, down the road, you can add a sub. Otherwise, I think the RF-7s will do nicely, if you can afford 'em.
AFAIK, no poster has yet addressed the signal source and preamp issues. Is a CDP the only signal source? Has any thought been given to a preamp?
Given all of the above, I will immodestly suggest that an "El Cheapo" be constructed using Dynaclone Z565 O/P trafos. "El Cheapo" is a challenging, but quite doable, 1st project. 6 WPC in triode mode and 12 WPC in ultralinear (UL) mode will be quite adequate in combination with the high efficiency Klipsch speakers. A separate preamp is not needed, if a CDP is the signal source. Even employing good O/P "iron" and some premium parts will not raise costs above $500. 😀 If "El Cheapo" interests you, read its LENGTHY saga here.
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Thats only part of it. Lets say you find THE amp. A few years down the road there is a better amp. And then.......
A lot of time? Well I have been building amps (tube and SS) for over 40 years. If you count all of the guitar amps there must have been well over a hundred, I can't remember them all. My problem is I like them all. I can see 11 from where I am sitting in power levels from 2 WPC to 200 WPC.
I found that one hard to believe, and I am an RF engineer so I understand db's. One day I took my 2 WPC 45 based Tubelab SE over to visit my friends 106 db Lowther based horns. It was loud playing Money for Nothing at half throttle. According to theory I should be able to duplicate that loudness if I fed 200WPC to my 86 db Yamahas. It doesn't work that way. Once the speaker cones are moving as far as they will go, more power only makes more distortion, and possible dead speakers. On the Yamahas anything more than about 30 WPC is wasted. There is somehing "effortless" about having an amplifier thay will NEVER see clipping though.
You make a good point about flatness. The KLF-10s have pretty much the same frequency response spec and it really *feels* like I have a sub sometimes. I should sweep them once to see how low they really go.
Tubelab said:
The Boston Acoustic A60s I have in my shop are similar. The cone moves at low frequencies but you just can't hear it. To be fair these speakers were refoamed by me using foams that are stiffer than they should be IMO. They sounded better when they were crumbly.
You could still use the ST-70 kit but I'd recommend to wire it in triode mode and ask for the SS rectifier option.
-> triode mode for better damping, I only have experience with the RF-82 and those really need to be well controlled, very difficult to do that with a low damping tube amp in combination with the music you like.
-> SS rectifier for cleaner bass (most metal needs real high definition in the bass)
One other thing to remember is that the greater the efficency of the speakers, the more sensitive they are to the noise floor and hum etc from the amp. Those Klipsch speakers will bring the background noise up 12dB/W-M over a set of 90dB/W-M efficency speakers.
What is un-noticable hum with the 90dB speakers will be quite noticable with the 102db/W-M ones.
I've got a graph somewhere that I plotted back in the late 70s where I tried to plot speaker efficency vs required power with background noise as a second plot. I had a hard time convincing some people that it mattered.
What is un-noticable hum with the 90dB speakers will be quite noticable with the 102db/W-M ones.
I've got a graph somewhere that I plotted back in the late 70s where I tried to plot speaker efficency vs required power with background noise as a second plot. I had a hard time convincing some people that it mattered.
To be frank, I prefer the Tubelab amps (both SE) to the ST-70 (VTA-70, actually) when doing "serious" listening. Granted it still sounds good, but those horns are sooo revealing. So much so that I can't even listen some some poor recordings because they drive me batty. The VTA-70 also puts a fair amount of hiss out of those speakers, again because of the sensitivity as Gimp mentioned, but this is really only noticeable during serious listening sessions (alone, in the dark, sitting right in front of them).
For those times, a small SE amp is the way to go. My Tubelab SE is dead quiet...I have to put my ear right over the tweeter to hear any sort of noise. The Simple SE is quiet too and is more fun for rock and other beat-heavy genres. Both amps have zero hum, but I took steps to ensure that.
For those times, a small SE amp is the way to go. My Tubelab SE is dead quiet...I have to put my ear right over the tweeter to hear any sort of noise. The Simple SE is quiet too and is more fun for rock and other beat-heavy genres. Both amps have zero hum, but I took steps to ensure that.
soooo... i need to find an amp that want over-reveal the horns. will the mk lll with kt 88tubes get me there?
I think the takeaway from this discussion is that with super efficient speakers, power is not the primary concern. This gives you many possibilities to explore. Hard to say what you'll like the most.
You might look for something reasonably priced in the 5-10W range and move up from there. You will very likely end up with multiple amps that you'll swap in and out as your mood dictates.
You might look for something reasonably priced in the 5-10W range and move up from there. You will very likely end up with multiple amps that you'll swap in and out as your mood dictates.
Bonus to having multiple amps - you already have the power needed to bi- or tri-amp if you want to in the future 😀
My Mark III get along just fine with my Klipsch Chorus II, despite being capable of delivering way more power than the speakers will ever need.
I get ear fatigue quickly from the ST70, but I've already decided that the VTA driver board could use some improvement. Way better than the stock board, but it has too much gain (part of the reason for the excessive white noise). I'll be modding it to convert the LTPs to use 12BH7s at some point, but I think a proper LTP with a 10M45 or similar under it would perform a little better. It sounds marginally better in triode, but I haven't played with the feedback circuit in that case.
I'll be trying a Simple PP with the KLFs soon...once I have it properly secured to a breadboard. We'll see how it sounds.
I'll be trying a Simple PP with the KLFs soon...once I have it properly secured to a breadboard. We'll see how it sounds.
I like the 12BH7 in the splitter socket. I'll have to go look up the schematic for the VTA board and see if it shares much similarity with the Poseidon drivers I've got in the Mark III.
http://i69.photobucket.com/albums/i43/Ty_Bower/Mark III/drivertubes.jpg
http://i69.photobucket.com/albums/i43/Ty_Bower/Mark III/drivertubes.jpg
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