KeithL
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Posts: 10,261
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Post by KeithL on Feb 22, 2017 10:49:45 GMT -5
Good point, though. In general, because there's a lot of power involved, building a power amplifier from a kit does have the potential to result in a house fire or even bodily harm - especially if you don't follow the directions scrupulously. And, in that regard, tube amps are far more dangerous - because a misplaced insulator, or a wire touching the case, can easily result in lethal voltage being present on the chassis, or someplace else unexpected. This is true of anything that runs off the AC line, and even many battery powered devices, but the power supply in a tube power amp is definitely among the most dangerous. This is why anyone who is not very familiar with safety around lethal voltages should stick with kits with proper and detailed instructions... Unless you're very familiar with both safety and design considerations for high voltage, you shouldn't be messing around with modifications and home-designs... You really can burn down the house or kill yourself by putting a part with the wrong rating in the wrong place (and it's more likely with tube equipment because the voltages are higher). I would also advise reading the instructions through BEFORE starting, and asking lots of questions if anything seems unclear. I would also strongly advise, yet again, to follow any instructions about the ORDER in which you do the various steps. For example, in many tube amps, especially vintage ones, turning the amp on with some of the tubes removed may be a recommended test or diagnostic step. HOWEVER, with some designs, turning the power on with certain tubes removed will actually cause certain voltages to exceed ratings - to the point where the amp will be damaged or destroyed. (So always follow the instructions EXACTLY.... and be very careful when messing with existing equipment.) Just fyi, building a tube amp with 4-500 volts dc is hardly the same as an Ikea bookshelf. You must have some idea what you're dealing with. Oh, of course. I was just making a dumb joke, but you raise a valid point. I'd hate for some forum lurker to inadvertently destroy their gear or injure themselves because I was tossing around false equivalence of building an amp kit to assembling flat-pack furniture. |
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Post by saru on Feb 22, 2017 12:38:02 GMT -5
Well, now that audiobill and KeithL have put the fear of God in me... how about that poll, huh? Practically neck and neck. I wish I'd had the foresight to put in an "other" category to collect votes on stuff like a tubes option.
I am going to try to compare the XPA-1Ls to the XPA-200 later this week, even if it may not be the ultimate solution. I ordered some basic full-range speaker cables off Amazon that I can pull the amp ends apart and not worry about cutting apart my AQ cables for this test; they should get here tonight. Maybe as early as tomorrow, I can do some A/B listening and see what differences I can hear.
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Post by Gary Cook on Feb 22, 2017 13:30:16 GMT -5
We can debate this forever and get nowhere plus I think you were taking it a bit more serious than I intended, perhaps you missed the wink, maybe a larger one next time; As for sensitivity to speakers I recall that your Bob Latino M125 tube mono-blocks require output binding posts set up for 4, 8 or 16 ohm speakers. That's what I meant by impedance sensitive, don't have that with SS amps. I'm not sure that I understand how you could say that someone who upgrades from, say, an XPA-100 to, say, XPA-1 is only doing it for the loudness. In my case I upgraded to XPA-1L's mostly for the XLR balanced connections to eliminate a slight induced noise issue from the 5 metre long RCA's. I certainly didn't do it for loudness, the XPA-1L's have no more power than the XPA-5 running 2 channels. As I said, agree to disagree, you post your opinions and I post mine. Gary...I do disagree BUT will admit I came off a bit strong from a bad day. My apoogizes for sounding rough. As far as NOISE coming from RCA compared to balance I never really heard noise from my receivers or pre-amps from pass ownership unless I saw it on a graph...but I am NOT contending that you physically did not hear noise. Myself, I have never heard actual noise from an RCA connection and other audio enthusiasts have felt the same. Again everyone is different. As far as the m125's being sensitive b/c of output binding posts my m125's are set for 6 & 8ohm's. I could have set them for 4,6, & 8 ohm. Depending on the speaker. Saying that I could set my B&W's to 6ohms but according to B&W of North America they perform better with an 8 ohm setting. The cost factor I THINK is around $30.00 in order to have those options for different ohm settings which I would think some people would like and take advantage of especially since the option is so reasonable in price. As far as the TUBE sound I enjoy it quite more than SS with all genres most especially JAZZ & CLASSICAL, but I will admit Floyd & Clapton sounds so detailed on the m125's, so I cannot exclude R&R. Again, sorry for the rough talk, Frank Hi Frank, thank you but no real need, on here we can debate things without malice. As an explanation, the necessity for different binding posts was simply an example of speaker sensitivity, not an example of wasted cost. A response to your claim that tube camps weren't speaker sesnitive, when plainly they are. They are also cable impedance and capacitance sensitive for the same reasons. A lot of the myths surrounding cables comes about from tube amps sensitivity to input and output loadings. Just my opinion of course. In regards to the noise, it was a very faint and intermittent buzz, only heard in silent passages. Keeping in mind that I have 5 metre long interconnects as the XPA-1L's are each located next to their respective speaker with very short speake cables. I could go for many days and not hear it plus no one else in the family seemed to notice. As a result it was not an issue that I lost any sleep over. I finally traced it to the ice maker in the fridge, not that I was looking for it at the time, pure co incidence. When I changed over from the USP-1 to the XSP-1 I also took advantage of the XSP-1's and XPA-1L's balanced discrete circuitry and installed XLR interconnects. Bingo no more buzz and the system is dead silent. Hence my comment that my reasons for moving to XPA-1L's had nothing whatsoever to do with increased loudness, in fact exactly the opposite was achieved. FWIW I find the 35 watts of Class A does a very fine job on music at my listening levels and tastes which extend from the classic rock of Creedence to the opera of Pavarotti. It's all music to me.  Cheers Gary |
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Post by leonski on Feb 22, 2017 14:06:09 GMT -5
saru? Does it really matter what anyone but YOU thinks? The SF speakers are a reasonable load and 90db sensitive. Even in a large room, 200 a side would be pretty loud. And if you are Listening at all, you'll hear the worst of any clipping. Don't forget, the speaker is rated at 22v. That is about 120 watts and I suspect a 'continuous' rating. The crossover probably has Caps rated at 2x or maybe 3x that voltage. I don't know what the rule of thumb is for speaker design. While it is rated at 22v, the instant peak voltage tolerance must be quite a bit higher. 300 watts is about 35v so maybe the caps are 70 volt? Anyway you slice it, unless you are in an acoustically Dead Room, picking power amps based on the 'max rated' power of a speaker is silly. What do I do with my Magnepans? They don't HAVE a rating. People successfully drive them with a kilowatt per speaker and bridge out or remove the tweeter fuse. My tweeter has a 4 amp fuse and given the crossover frequency of about 600hz (pretty low) represents about 1/2 the total power you could need. But fuses aren't 'brick wall' and will take quite a bit of current over the rating before popping. Time matters for that measure, too. I'm using 2x200 per speaker, cutting the lows about 55hz and running an additional 250 watts for the sub. And yes, assembly of a kit is a Detail Oriented activity. From making sure the tube sockets are installed correctly (circuit board mounted are 'keyed' and go in only 1 way) to lead length and 'dress' as well as bundling or braiding, you need a certain skillset. Learning how to solder from somebody other than a plumber who installs copper pipes would be a good idea. And get a good station, like maybe the Hakko? Don't buy cheap hand tools, either. Get GOOD stuff which will be a near-lifetime investment. Plan on a couple hundred for tools and a METER, too, for that matter. www.tubedepot.com/products/tubecube-7-stereo-vacuum-tube-amplifierFor 200$, this might be a good 'intro' to tube kits. I don't know how good the instructions are. But getting enough Tube power for the SFs might be $$$. And potentially worth it? A school of thought thinks tube stuff plays 'louder' than the watt rating while still others collect tubes for 'rolling' like a sports fan collects baseball cards. Once you start on that path, you're a Goner! And I don't know how 'compatible' the SFs are with tube gear. Huge impedance swings interact with the low output impedance of tube gear and produces frequency excursions which can be audible. I can assemble flat pack furniture nearly blind-folded, but would NEVER try an amp kit except after refresh of my once near mil spec soldering skills. And in a well-lit space at that. Let everyone know what you think of the 1L V XPA-200 comparison. Within the limits of the amp, I'm betting on Surprise! in the Good Way. |
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Post by saru on Feb 22, 2017 14:34:31 GMT -5
saru? Does it really matter what anyone but YOU thinks? Not one iota đŸ˜„ But I value the many informed opinions and advice of my fellow Loungers, and I appreciate everyone's input in helping me to make a decision here and there. Seriously, thanks to everyone for chiming in, it has been a very educational thread! And I promise to be super-careful (or just hand it over to a professional) if I ever so much as step in the direction of an amp kit. |
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Post by monkumonku on Feb 22, 2017 14:54:22 GMT -5
saru? Does it really matter what anyone but YOU thinks? Not one iota đŸ˜„ But I value the many informed opinions and advice of my fellow Loungers, and I appreciate everyone's input in helping me to make a decision here and there. Seriously, thanks to everyone for chiming in, it has been a very educational thread! And I promise to be super-careful (or just hand it over to a professional) if I ever so much as step in the direction of an amp kit. Having built my ST-120 amp, here's some thoughts about that. First of all, Bob Latino makes excellent gear and it was a pleasure putting the kit together because the instructions were so clear. That said, my advice is to only build a kit if you really enjoy that kind of stuff - don't do it just to save money. I wanted to build the kit because of the challenge of doing so as well as my curiosity since I had heard so many good things about those amps. When I finished and got to the big point of actually trying it, to my disappointment it didn't work properly. I was fortunate enough to get some much appreciated help to troubleshoot, and it turned out I hadn't done some things properly, even though I thought I had followed every bit of the directions. Were I to build another kit I would now have the benefit of hindsight and avoid the mistakes I made the first time, having learned from that. So it's kind of like learning from trial and error which prepares you for doing the next one except unless you do build that next one(s), then it is a moot point. Everything turned out well - the amp works fine and I love it. But like I said, my advice would be unless you really enjoy building kits, let an expert (like audiobill) do it. And it wouldn't hurt to practice making some inexpensive device just to get some experience. |
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Post by leonski on Feb 22, 2017 17:40:22 GMT -5
monkumonku,
You make me wish I had more sensitive speakers. Maggies take a LOT of power. They are an easy load, otherwise, and I've seen a few intalls using tube amps for the highs and SS for the bass. That particlular system used
a Marchand Crossover at line level. So the amps appeared to have more power to the speaker.
I think I could successfully complete a 'Latino kit. I worked as a tech for 2 decades + fixing most of the equipment in a wafer fab used in the manufacture of Integrated Circuits and later 'discrete' devices.
I'm going to the website, check it out and see how much $$ I don't have!
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Post by monkumonku on Feb 22, 2017 17:47:37 GMT -5
monkumonku, You make me wish I had more sensitive speakers. Maggies take a LOT of power. They are an easy load, otherwise, and I've seen a few intalls using tube amps for the highs and SS for the bass. That particlular system used a Marchand Crossover at line level. So the amps appeared to have more power to the speaker. I think I could successfully complete a 'Latino kit. I worked as a tech for 2 decades + fixing most of the equipment in a wafer fab used in the manufacture of Integrated Circuits and later 'discrete' devices. I'm going to the website, check it out and see how much $$ I don't have! My main mistakes were in inadequate solder joints. There was one wiring mistake and also some instances of dressing the wires better/more efficiently. I had built a couple of Dynaco kits before but that was way back in college days, and I hadn't really done much soldering since then. If you worked as an electronics tech then I think as long as you carefully follow the excellent instructions, you should do fine. Besides, you'll probably wind up with the M-125's to drive your Maggies and those are simpler to wire.  Make sure to post a pic in the Post Your Latest Purchase thread! |
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Post by leonski on Feb 22, 2017 18:59:22 GMT -5
monkumonku,
This would be one of the few ways to tempt me to go the tube route.
The project is WAY over budget the way I'd have to do it.
First? Biamp, so I'd need 4x of the M-125s. That would be about enough power.
Second? MiniDSP crossover with cal'd mic. Buys nearly 3db MORE power since amp no longer produces entire spectrum.
Probably have to go with a single 2x8 and to to the machine shop for a bracket to hold the Neutrick Connectors.
Total Cost would be OVER 5000$, once you added in Tubes. Without spares, even! Additional cables needed, too, and due to run length, they'd best be Balanced. OUCH! +500$
Anybody want to buy a gently used Kidney?
I don't see it, but it MIGHT come to an additional outlet drop. That's ANOTHER 600$ or more.
Time? For this, I'd give it away, but I'd ALSO have to dig into my panels, disconnect the crossover and ReWire to the binding posts for direct-2-amp connections. And for the panels? 4ohm tap would be the obvious starting point.
Any idea how many STAPLES you need to remove to pull the speaker's sock? It would appear that Magnepan owns Stock in Swingline! Figure 1 days labor to modify speakers, alone.
My soldering skills are fairly current. I just bought a new Hakko and junked out my Unger Imperial of 40 yrs age. I have ALL the hand tools needed including auto wire strippers, solder wick, Thin (.062") solder, though new formulations of solder
are available, so I might go with a modern silver-containing compound.
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Post by bluemeanies on Feb 22, 2017 19:01:17 GMT -5
monkumonku, You make me wish I had more sensitive speakers. Maggies take a LOT of power. They are an easy load, otherwise, and I've seen a few intalls using tube amps for the highs and SS for the bass. That particlular system used a Marchand Crossover at line level. So the amps appeared to have more power to the speaker. I think I could successfully complete a 'Latino kit. I worked as a tech for 2 decades + fixing most of the equipment in a wafer fab used in the manufacture of Integrated Circuits and later 'discrete' devices. I'm going to the website, check it out and see how much $$ I don't have! If you buy and decide to have that built by someone other than yourself...I HIGHLY recommend audiobill. If you choose to jump in the pool and get wet the best of luck and certainly again audiobill could figure out any problem issues. |
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Post by leonski on Feb 22, 2017 19:34:24 GMT -5
Thank you Mucho for the AudioBill 'tip'. I wish I Could afford to build a quad of these guys. It would be Fun.
I have 100% confidence I could build 'em though. I built my first 'kit' when I was about 13 or 14 in the form of a Knight Kit (ever hear of them?) Star Roamer SW receiver.
Later I built a VTVM which I wish I had kept.
My work life was always technical with maybe 1/4th of it actually spent 'fixing' stuff.
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Post by Gary Cook on Feb 22, 2017 20:27:51 GMT -5
I've probably assembled from kits over 100 power amplifiers, a handful of which were based around tubes. It was one of the ways that I paid my way through university. The recommendations for caution in jumping in stone cold is well founded. Assembling a tube amp is not the place for virgins in reading and interpreting circuit diagrams and detailed instructions. Not to mention the actual art of soldering and the wiring preparations involved. For sure it's not rocket surgery, but as with most things, experience in simpler assembly beforehand is most helpful.
Cheers
Gary
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Post by monkumonku on Feb 22, 2017 20:35:08 GMT -5
monkumonku, This would be one of the few ways to tempt me to go the tube route. The project is WAY over budget the way I'd have to do it. First? Biamp, so I'd need 4x of the M-125s. That would be about enough power. Second? MiniDSP crossover with cal'd mic. Buys nearly 3db MORE power since amp no longer produces entire spectrum. Probably have to go with a single 2x8 and to to the machine shop for a bracket to hold the Neutrick Connectors. Total Cost would be OVER 5000$, once you added in Tubes. Without spares, even! Additional cables needed, too, and due to run length, they'd best be Balanced. OUCH! +500$ Anybody want to buy a gently used Kidney? I don't see it, but it MIGHT come to an additional outlet drop. That's ANOTHER 600$ or more. Time? For this, I'd give it away, but I'd ALSO have to dig into my panels, disconnect the crossover and ReWire to the binding posts for direct-2-amp connections. And for the panels? 4ohm tap would be the obvious starting point. Any idea how many STAPLES you need to remove to pull the speaker's sock? It would appear that Magnepan owns Stock in Swingline! Figure 1 days labor to modify speakers, alone. My soldering skills are fairly current. I just bought a new Hakko and junked out my Unger Imperial of 40 yrs age. I have ALL the hand tools needed including auto wire strippers, solder wick, Thin (.062") solder, though new formulations of solder are available, so I might go with a modern silver-containing compound. Sounds like you're talking yourself into it.  I won't comment on biamping - I figure the owners of the M-125's can chime in as to what they can drive. My ST-120 is 60 watts per channel but I use it in triode mode which makes it more like 32 watts per channel and it never feels like it is straining. My speakers are probably easier to drive than Maggies (I believe the efficiency is 87 db) but it does so effortlessly. I used to have XPA-1's - how's that for a contrast? Granted, I had different speakers when I had those amps but there seems to be no lack of power with the ST-120 even in triode mode. Also, I don't believe the M-125 has balanced inputs. |
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Post by leonski on Feb 22, 2017 21:29:45 GMT -5
A couple MINOR points. Efficiency is a %age, not db/watt/meter.
Maggies are very easy to drive. They are both tube and SS friendly. Only fly in the ointment is very very LOW sensitivity.
AT maggie HQ in White Bear Lake, they have (or had?) a small tube amp driving the Demo Speakers in the Lobby. Maybe even a Stereo-70? I dont' know.
No balanced ins? I'd have to see if I can keep the runs real short, than.
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Post by deltadube on Feb 22, 2017 21:38:22 GMT -5
get the xpa 1 mono blocks...
cheers
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Post by saru on Mar 2, 2017 9:02:00 GMT -5
So, I managed to swap the XPA-1L's into my 2ch system last week, using a set of cheapy speaker cables I bought off Amazon that I could stretch apart to make them fit the gap in cable posts on the amps. I was struck at how flat and suppressed the music sounded when pushed through this setup, and I knew it wasn't the fault of the monoblocks. Took me a little while to find a solution: I came across some nice-quality banana-to-spade adapters that added just enough length to allow my Audioquest cables to stretch the cable post gaps as spade connections. I received those a few days ago and promptly swapped out the cheapy cables for my good ones -- and lo and behold, the dimensionality that I could perceive in the music had been restored! I know, I know -- always take expensive cable SQ claims with a huge grain of salt, but in this case, I noticed a significant difference where I had not expected one before.
Anyway, I've had a bit of time to listen to the system with the XPA-1Ls in place. While the music does sound excellent, I haven't noticed it being significantly better than when I was running with the XPA-200. Not to say that it's not better, just that I haven't picked up on the difference yet. I might grab the XPA-200 back from the theater room so that I can do some side-by-side switching. However, I have noticed that the heat generated by the monoblocks in my 2ch cabinet is a problem, even with the open back (the cabinet, by the way, is a BDI Mirage: glass door front and wooden sides). While I could leave the XPA-200 on all day long with no ill effect, the XPA-1Ls put out too much heat to leave on for more than just the time I'm actively using them. So, while I would still like to upgrade from the XPA-200 at some point, I would prefer to do it with something that generates less heat than the XPA-1L.
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Post by Gary Cook on Mar 2, 2017 15:41:22 GMT -5
However, I have noticed that the heat generated by the monoblocks in my 2ch cabinet is a problem, even with the open back (the cabinet, by the way, is a BDI Mirage: glass door front and wooden sides). While I could leave the XPA-200 on all day long with no ill effect, the XPA-1Ls put out too much heat to leave on for more than just the time I'm actively using them. So, while I would still like to upgrade from the XPA-200 at some point, I would prefer to do it with something that generates less heat than the XPA-1L. I have had a number of Emotiva amplifiers (XPA-2, XPA-3 XPA-5, XPA-100, XPA-1L) as well as countless other brands including a large number of DIY and I have not noticed (or measured) any additional heat from the XPA-1L's. Except when in Class A of course, they do generate a bit more then. But otherwise they run as cool as any other Class AB amplifier. Possibly it's that there's 2 of them together plus taking up twice as much air space in the cabinet as one XPA-200 that creates and impression of additional heat. Cheers Gary |
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Post by saru on Mar 2, 2017 17:08:18 GMT -5
However, I have noticed that the heat generated by the monoblocks in my 2ch cabinet is a problem, even with the open back (the cabinet, by the way, is a BDI Mirage: glass door front and wooden sides). While I could leave the XPA-200 on all day long with no ill effect, the XPA-1Ls put out too much heat to leave on for more than just the time I'm actively using them. So, while I would still like to upgrade from the XPA-200 at some point, I would prefer to do it with something that generates less heat than the XPA-1L. I have had a number of Emotiva amplifiers (XPA-2, XPA-3 XPA-5, XPA-100, XPA-1L) as well as countless other brands including a large number of DIY and I have not noticed (or measured) any additional heat from the XPA-1L's. Except when in Class A of course, they do generate a bit more then. But otherwise they run as cool as any other Class AB amplifier. Possibly it's that there's 2 of them together plus taking up twice as much air space in the cabinet as one XPA-200 that creates and impression of additional heat. Cheers Gary Fair enough. I guess my concern is not so much with the heat output of the individual amps, but with the increased heat inside the cabinet and its effect upon the components contained within. That said, I had experienced something funny this afternoon. I found a few minutes to have a listen, and I noticed that the soundstage seemed to be shifted almost entirely to the left speaker. I went up to listen closely to each speaker, and music was coming from both of them just fine, but the overall impression from the listening chair was definitely skewed to the left. I actually picked up on this yesterday but I don't think it was as apparent. I got behind the cabinet to check all the connections and they were solid. So I tried just setting the XSP-1 to standby for a minute (I usually leave it powered on), then switched it back on and tried some music again... and the soundstage was back to center! Furthermore, I feel like the music was more forceful and present than before... so that was an odd preamp glitch throwing off my earlier impressions! |
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Post by leonski on Mar 2, 2017 20:37:10 GMT -5
You CAN'T have a class 'A' amp which does NOT generate plenty of heat. That's why a proper 'A' amp weighs at least 1lb per watt of 'A' output or more.
There are potential workarounds, but at the Krell / Pass level of expense.
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Post by gearhead2003 on Mar 2, 2017 23:57:25 GMT -5
Option 5: Considering your speakers are $10,000 speakers. I would get a pair of XPA-1 gen 2's. There is a difference in control and dynamics between the XPA-1 gen 2's and the XPA-1 L from my subjective listening observations. In fact, I also heard the same speaker with FOUR XPA-1 L's and it still couldn't control it as well as a pair of XPA-1 gen 2. Or get four XPA-1 gen 2's and bi amp that sucker. Either way would be great. However ... there is a chance you won't hear any difference. If your experience so far has been that electronics make no difference at all to your sound, then the chances are high that you won't hear any difference. In that case either one of your choices would be better. HELL YES GO WITH THAT HE SAID! |
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Just fyi, building a tube amp with 4-500 volts dc is hardly the same as an Ikea bookshelf.
Make sure to post a pic in the Post Your Latest Purchase thread!
