So I have owned a Decware Zen Select for years now. I love the little amp and I have yet to find another amp that comes close for the price. I am having an issue with tube gear, my own and other pieces I have heard. The bass is unacceptable when listening to modern music. I am increasingly finding all tube gear greatly lacking when it comes to listening to any current music that has serious bass. This includes amps and preamps connected to SS amps. Is this just the nature of the beast? Amazing midrange and treble at the cost of bass or is there something that can be done? Is this solely a function of the output transformer being deficient in some way? If you don't believe me take a listen to some Pendulum, Kruder & Dorfmiester or Ludacris.
This may just be a cranky rant. What I want it in a system is all the wonderful aspects of a SET amp but with accurate and powerful bass. Is that to much to ask?
This may just be a cranky rant. What I want it in a system is all the wonderful aspects of a SET amp but with accurate and powerful bass. Is that to much to ask?
Depends on how much money you have.
Even for a subjectively expensive tube amp, the bass speed cannot satisfy everyone. You should have special speaker suitable for tube amps.
I do, I have the parker 98s but I have tried other speakers.
I should point out this is more of a frustrated vent then anything. Personally I think the fix is is a speaker that is efficient and has an active low end. Its just a shame there isn't some new technology that lets us have it all.
I should point out this is more of a frustrated vent then anything. Personally I think the fix is is a speaker that is efficient and has an active low end. Its just a shame there isn't some new technology that lets us have it all.
You just need to have the right combo. You are not going to get much of the eyeball rattling bass with something single ended anyway. My push/pull 30 watt mono wurlitzer tube amplifier shakes the house. I am using a single 15inch Magnavox woofer in an old cerwin-vega cabinet. Any music from rap to country, rock to jazz, sounds (and feels) awsome!
I don't have any problems with any lack of bass in my hollow state designs. These feature bass with "authority", none of that underdamped sloppiness, and accuracy such that quiet bass passages that simply aren't heard at all with most solid state amps become clearly audible. Like you, I listen to a lot of bass-heavy Techno. You don't need lotsawatts either, as the designs I've done so far come in at 30W and 40W.
To get good bass in any hollow state design requires, first and foremost, a good OPT. Cheap OPTs sacrifice the low end for smaller cores, cheaper lamms, less wire. In a lot of older designs, this was done deliberately to reduce hum. If your OPTs are smaller than your power xfmr, they're sonically inadequate.
Another problem was a lack of decent coupling capacitors. Back in "the day", there wasn't much besides wax paper capacitors and ceramics. While the paper capacitors packed a lot of uF's in small packages, they tended to leak (current, not oil or wax) and throw off the bias of the stages they coupled. Ceramics didn't have that particular problem, but didn't come in sizes that would make for good open loop performance at the low end.
You can have a frequency response as flat as a billiard table, but if it's NFB that's flattening the response, bass is likely to suffer. If the open loop frequency rolls off, so does the NFB, and the closed loop gain increases. Less NFB means less effective NFB that may not be damping the woofers adequately. These days, getting decent coupling capacitors -- like AuriCaps -- isn't difficult in sizes needed for good open loop performance. Of course, it helps to use DC coupling as much as possible. I do that as well.
I think most important is right combination of amp and speaker.
Pls go make a pair of BiB with Fostex Fe206en it will shake your walls. Also Fostex Recommended cab for 208 sigma plays down to 30hz loudly.
If want to go extreme use a 20/25hz tapped horn with your fav speaker.
I request you to think out of the box (ss way) because tube is a voltage devise and operate differently than transistor. I personally suffered this dilemma when I migrated from ss many many moons ago.
Tube and SET is ok for deep bass no problem but it is different (and better) that SS bass. Condition for acheiving good bass from tube is 'FRESH THINKING.'
Pls go make a pair of BiB with Fostex Fe206en it will shake your walls. Also Fostex Recommended cab for 208 sigma plays down to 30hz loudly.
If want to go extreme use a 20/25hz tapped horn with your fav speaker.
I request you to think out of the box (ss way) because tube is a voltage devise and operate differently than transistor. I personally suffered this dilemma when I migrated from ss many many moons ago.
Tube and SET is ok for deep bass no problem but it is different (and better) that SS bass. Condition for acheiving good bass from tube is 'FRESH THINKING.'
To get good bass you need either very big transformers or big transformers plus enough negative feedback. It can be difficult to add enough feedback to a SET amp as the open-loop distortion may be too high, so push-pull is better.
If you like SET for mids and highs, then maybe use SET for mids and highs and P-P for bass?
If you like SET for mids and highs, then maybe use SET for mids and highs and P-P for bass?
I got good bass using an EL156 SEUL with a Hammond 1627SEA transformer. The 1627SEA is BIG and a little GNFB helped too. It's not quite in the same territory as my Threshold S/500 (which is in a class of it's own bass-wise), but with 15" woofers in my UREI 813As, there is some serious low-end content.
Fostex is a no go for real bass even in big horn man !!!
On the other hand all that response here give the solution : a lot of iron like my 25 square centimeters OPT i use in a PP amplifier (6P3S) with Triangle Alteea EX : bass like a Hurricane !
I'll have to agree with Miles. The transformers used on the single-ended kit I am selling weigh about 8lbs each and response is flat down to 20Hz. Perfectly balanced bass, no problem. How the OPT windings are wound; ie. sandwiched. interleaved; also has a lot to do with the performance. If I'm not mistaken, the OPTs by Decware are pretty light. Not meaning to discount Decware amps in any way whatsoever. So to try to answer your question: Possibly look into replacing the output transformer.
Last edited:
Lots of high quality output iron, and a very stiff, low impedance power supply will do wonders for the bass performance of even very small SE amplifiers.
I listen to a lot of techno and other bass heavy material with an 8W per channel 300B SE amp of my own design and have plenty of good bass. Of course the speakers are 11 cu ft Onkens with 16" Iconic woofers in them - very efficient and good down into the low 30s.
The Decware Zen Select while a good little amplifier but is not noted for its great bass. Does lots of things well, but it was I think intended as an entry point into the tube world.
I listen to a lot of techno and other bass heavy material with an 8W per channel 300B SE amp of my own design and have plenty of good bass. Of course the speakers are 11 cu ft Onkens with 16" Iconic woofers in them - very efficient and good down into the low 30s.
The Decware Zen Select while a good little amplifier but is not noted for its great bass. Does lots of things well, but it was I think intended as an entry point into the tube world.
Last edited:
I'm with Miles and Kevin. You need some iron to give SE some kick and you need speakers that are friendlier to drive at low frequencies. I have Edcor CXSE iron in my Simple SE. Couple that with some big KT88s and it has copious bass on my 98dB speakers. I also listen to a lot of Techno/Trance (AvB, etc) and can't listen to it with my smaller SE amp (300B). The speakers (Klipsch KLF-10) have *deep* bass, perfect for this type of music, but they need the push from those extra watts and the big iron.
With a PP amp, they are a breeze to drive. Bass is faster and more controlled with a small PP amp than with the big Simple SE, but that makes sense given the topology. Every amp has compromises. As I have waded deeper into this hobby, I've come to realize this. The DHT SE amp shines for classical, vocals, live performance, etc. My PP amps rock when I want to. The Simple SE is a compromise between the two extremes and as a result I use it the most. 🙂
My older speakers are reasonably efficient, but are acoustic suspension which can be notoriously difficult to drive. The Simple SE can drive them, but they sound much better with a PP amp that has some feedback.
With a PP amp, they are a breeze to drive. Bass is faster and more controlled with a small PP amp than with the big Simple SE, but that makes sense given the topology. Every amp has compromises. As I have waded deeper into this hobby, I've come to realize this. The DHT SE amp shines for classical, vocals, live performance, etc. My PP amps rock when I want to. The Simple SE is a compromise between the two extremes and as a result I use it the most. 🙂
My older speakers are reasonably efficient, but are acoustic suspension which can be notoriously difficult to drive. The Simple SE can drive them, but they sound much better with a PP amp that has some feedback.
This is from the Parker site:
"The Model 98 will work best in a vented configuration, but as with any kit, experimenting with different cabinet types and volumes are always an option. The cabinet configuration I offer is a vented design. The cabinet volume for this kit is optimal at 1.25 cubic feet. At this volume the optimal port is 3" in diameter and 1.5" long. The system specs for this setup are 96 db efficient, 2 ohm impedance and a frequency response of 40-40khz."
The bold is mine. They have a 2 ohm impedance. That's not necessarily the best situation for any tube amp even if it's got taps for it. You may get better bass from a speaker that likes a bit of series R from the amps.
I have a pair of medium sensitive 3-way BR speakers. And the answer is:.....Brute Force!
Big Iron, High damping factor, primary impedance at least 5 to 6 times ra of the output tube. Triode connection. This will reduce available output power so BIG, reasonably low ra tubes needed, 845, 813 in triode, etc......and just maybe a little nfb on top.
This gives excellent bass performance from SE ......... but seriously, a pair of apropriate speakers is of course the more sensible way.
/Olof
Big Iron, High damping factor, primary impedance at least 5 to 6 times ra of the output tube. Triode connection. This will reduce available output power so BIG, reasonably low ra tubes needed, 845, 813 in triode, etc......and just maybe a little nfb on top.
This gives excellent bass performance from SE ......... but seriously, a pair of apropriate speakers is of course the more sensible way.
/Olof
Have you looked at the First Watt F4? It was designed as a "follower" amp to be used with SETs. There is an article here that describes it all
6moons audio reviews: FirstWatt F4
6moons audio reviews: FirstWatt F4
I've added a subwoofer and it helps but it is far from what I would consider ideal. Going fully active is something I have considered and it may be a path I persue. It may also be time to upgrade the OPT or get another amp. If I wanted to upgrade the OPT of my zen select though, where should I be looking.
What brought this whole thing about was my visit to high end shop. They had a pair of Wilson Watt/puppys that I got to listen to. I loved the detail, midrange and bass but it was missing the 3d imaging I get with my SET. This visit also pointed out to me that my system sounds damn good when compared to systems costing tens of thousands more. Now I just need to figure out how to bring it to that next level.
What brought this whole thing about was my visit to high end shop. They had a pair of Wilson Watt/puppys that I got to listen to. I loved the detail, midrange and bass but it was missing the 3d imaging I get with my SET. This visit also pointed out to me that my system sounds damn good when compared to systems costing tens of thousands more. Now I just need to figure out how to bring it to that next level.
+2
What I intend to do is drive a set of fullrangers (like audio nirvana or Fostex) high efficiency (about 94dB) in open baffles, augmented with 15" woofers in a MJK-style OB. I'll drive the full-rangers with a Tubelab Simple SE amp because this is where the tubes are really needed, and the augies with an inexpensive, but good, SS amp with an active xover in between at about 200 Hz or so.
This will be pretty inexpensive and it just makes too much sense not to work. No passive filters, good SE sound, plenty of power, inexpensive. Works for me. Oh, also if you are building the SE amp, you can use much cheaper OPT's because all that expensive iron is really only needed for the lower freq's.
I haven't decided yet on the exact components to use, but this is what I'm going to do. I'm always open to suggestions on component selection.
Last edited:
How are your room acoustic treatments? I would strongly recommend on doing it if not done already.
- Status
- Not open for further replies.