So I'm just winding up my Tubelab Simple SE and have really enjoyed the build (just need to wire it and find some junk speakers to test with). I'm planning on running it with some Omega 3 speakers I purchased (93dB) and I'm hoping I like the combo. I've never heard the speakers or the amp.
So here's my dilemma; I'm really enjoying the DIY thing and I want to build something else. However, most of the speakers I'm loving are just not that sensitive. Maybe the single driver Omega's will change my way of thinking when they're up and running (they are going to be in the office) but all the speakers I really love (so far) are only 86-88 dB. I don't think I could handle something like Tubelab's monster 845 SET (although I really wish I could) so I'm thinking something push-pull.
Obviously I love the idea of of a Tubelab Simple P-P but 18 watts really isn't going to swing 86 dB speakers. I think I'm going to need at least 35 watts to get where I want to be. So what do you guys recommend? Something like an Dynaco ST-70? I really hate the way the stock unit looks so I'd probably go for one of the clones and build my own chassis. Instead of the Dynaco should I look at something commercial or Chinese and try and mod? One of the Jolida amps or something from those Music Angel guys? I have nothing against Chinese stuff, I've lived in Beijing for quite a while, so I'm open to any suggestions.
Anyway, I'd love to hear everyone's recommendations for how best to feed my habit.
Thanks!
So here's my dilemma; I'm really enjoying the DIY thing and I want to build something else. However, most of the speakers I'm loving are just not that sensitive. Maybe the single driver Omega's will change my way of thinking when they're up and running (they are going to be in the office) but all the speakers I really love (so far) are only 86-88 dB. I don't think I could handle something like Tubelab's monster 845 SET (although I really wish I could) so I'm thinking something push-pull.
Obviously I love the idea of of a Tubelab Simple P-P but 18 watts really isn't going to swing 86 dB speakers. I think I'm going to need at least 35 watts to get where I want to be. So what do you guys recommend? Something like an Dynaco ST-70? I really hate the way the stock unit looks so I'd probably go for one of the clones and build my own chassis. Instead of the Dynaco should I look at something commercial or Chinese and try and mod? One of the Jolida amps or something from those Music Angel guys? I have nothing against Chinese stuff, I've lived in Beijing for quite a while, so I'm open to any suggestions.
Anyway, I'd love to hear everyone's recommendations for how best to feed my habit.
Thanks!
Doubling your power only buys you a few precious decibels. It's like the difference between the amp that goes to eleven, and the one that only goes to ten. Nigel won't ever be convinced, but it really isn't that much. If you're certain a pair of 6BQ5 won't be enough, you shouldn't settle for anything less than paralled push/pull KT88 per channel.
And if you get stuck the 'National Valve Museum' has this quaint 1000W design… if you can find the valves and transformers, and don’t mind the 3% distortion… MZ2-200 1kW Amplifier
Actually according to the MZ2-200 data sheet the amp can be scaled – less power (only 600W) at less distortion (1%) …
Good luck !
Actually according to the MZ2-200 data sheet the amp can be scaled – less power (only 600W) at less distortion (1%) …
Good luck !
I built a pair of 3CR-ti speakers (Parts Express DIY Project) and run them off an 18wpc P-P tube amp. Highly recommended! I love the sound. It's full, rich, images well, and is just plain enjoyable. It's also plenty loud. I listen to the likes of Dire Straits, Steely Dan, Il Divo, The Nylons, Tom Petty, Eric Clapton, Toby Mac, etc...
Just my 2 cents...
Mike
Just my 2 cents...
Mike
This sounds like what I'd be looking for. The 807 idea mentioned above sounds very cool (they look cool at least!) but I'm wondering if that might be a little too advanced for a noob.
Yup, that's the sensible way to go if power is paramount and experience is minimal. Try the kit at Triode, or at DynakitParts. Oddwatt has a clever KT88 kit too, 'cept I think it's pure class A only and won't give more than 25 watts.
for 807, look at any circuit for a 6L6 - they are virtually the same thing. Shoog has done some interesting stuff with 807s, and the STC datasheet for them shows an AB2 circuit at 75w from one pair iirc.
We are talking hifi designs aren't we? AB2?
Googling 6l6 brought up a number of guitar designs.
I've been looking for a number of months. Most common configuration is a PP pair sometimes ultralinear, but you wont get 50 - 60 watts from a pair with distortion less than 0.5% as per the STC data sheet we certainly aren't in class A, The STC dta sheet doesn't contain any info on ultralinear operation of the 807.
It would be easier to use the KT 88s as each device can dissipate higher power.
Alas i am committed to using the 807 so for me probably a sextet? (6) to stay in class A and get some reasonable power while configured as triode, and i would expect an easy 70 watts in ultralinear.
By the way the most significant number of designs i have encoutered that included 807's are in the ACRO transformer data sheet.
Check it out http://www.clarisonus.com/Archives/Trans/Acro55.pdf
Of course there are no constant current devices used in these old gems from Mr Hafler I believe.
I'm no expert so stand to be corrected.
Googling 6l6 brought up a number of guitar designs.
I've been looking for a number of months. Most common configuration is a PP pair sometimes ultralinear, but you wont get 50 - 60 watts from a pair with distortion less than 0.5% as per the STC data sheet we certainly aren't in class A, The STC dta sheet doesn't contain any info on ultralinear operation of the 807.
It would be easier to use the KT 88s as each device can dissipate higher power.
Alas i am committed to using the 807 so for me probably a sextet? (6) to stay in class A and get some reasonable power while configured as triode, and i would expect an easy 70 watts in ultralinear.
By the way the most significant number of designs i have encoutered that included 807's are in the ACRO transformer data sheet.
Check it out http://www.clarisonus.com/Archives/Trans/Acro55.pdf
Of course there are no constant current devices used in these old gems from Mr Hafler I believe.
I'm no expert so stand to be corrected.
hey-Hey!!!,
PP KT88 built as mono blocks, each with a Hammond 1650R( 5k a-a ), and a St.70 power TX would be quite simple. You can pick from a large number of schematics for the front end. It will be an excellent project as the power stage will be kept and various circuits can be tried as your skill level improves.
cheers,
Douglas
PP KT88 built as mono blocks, each with a Hammond 1650R( 5k a-a ), and a St.70 power TX would be quite simple. You can pick from a large number of schematics for the front end. It will be an excellent project as the power stage will be kept and various circuits can be tried as your skill level improves.
cheers,
Douglas
If you're committed to 807 in class A triode, good luck with power. To get an amp that plays appreciably louder than an 18 watter, you're talking at least 100W. That will take a PILE of output tubes and be a bear of a load for most driver stages. An advanced designer/constructor could pull it off. A non-expert will not.
Significantly more power could also be gotten by a pentode AB2 design. Again, that's do-able, but it's going to be a bit tricky and require both very high voltages and a capable driver stage. Feedback will be necessary, and best accomplished by multiple loops. Or tricky distortion compensation (e.g., Pete Millett's scheme). Not for a beginner.
The three constraints of significantly more power, the use of 807s, and being within the capability of a non-expert are not compatible. Pick two and we can go from there.
That pick two of three thing is always what kills me!
No, I'm not committed to the 807, just thought they were cool looking and someone else mentioned it might get me where I need (at least I think I need) to go. I hope to get any appreciable difference over an 18 watter I don't have to go to 100W. Other than something like the Dynaco mkIII, is there anything else in the 60W range?
Keep in mind that for something to subjectively sound twice as loud, it requires 10dB or so more power. The difference in loudness between 18 and 60W is noticeable but not a lot. More important, IMO, to perceived loudness is how the amp overloads and how it recovers. If you want to require that the amps not clip, three or four notches on the volume control represent some serious expenditure.
And if it's triode/class A, make that a LOT of expenditure, both on the amp, the power it takes to run it, and the air conditioning you'll need for the listening room. The efficiency is likely to be 35% or so, which means your output stage will have to be throwing off 180W from the plates for a 60W amp. Figure at least another 60-70W from the heaters. You've got some 500W space heaters there.
AB, ultralinear, and/or pentode starting to look better?
And if it's triode/class A, make that a LOT of expenditure, both on the amp, the power it takes to run it, and the air conditioning you'll need for the listening room. The efficiency is likely to be 35% or so, which means your output stage will have to be throwing off 180W from the plates for a 60W amp. Figure at least another 60-70W from the heaters. You've got some 500W space heaters there.
AB, ultralinear, and/or pentode starting to look better?
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