tube fanatic Posted February 10, 2014 Share Posted February 10, 2014 The guy mentioned that he didn't understand how to configure a single-ended pentode amplifier, or if it was even feasible. I'll openly admit I'm rank amateur, and just explained to the best of my knowledge. I mentioned "somewhat regulated" because I didn't want someone coming in saying that regulated screen supplies are a must or some such. I mostly work with simple 2 stage single-ended pentode circuits, and have never used regulated supplies for the screens, and have never had screen related issues. You explain why I never have these issues in your post above. This is why I shouldn't answer these sort of questions. I don't have enough technical knowledge to explain things in the correct manner, but I tried. I do appreciate the points however, and am not afraid of constructive criticism. I'm always on a learning curve. With regards to "stirring the pot", and I bring this up with no offense...but you have "tube amp designer" emblazoned above your avatar. I know you may be some sort of electrical or audio engineer just by the way you help folks out around here, and the technical prose of your posts. But I haven't seen any images of your products or projects, unless I missed them. I know you have your reasons, but the only reason I'm bringing it up is you called Justin Weber out basically demanding underside images of his amplifiers, which he did. IMHO, I feel it is only fair that you return the favor and show some of your work...even a above shot of a amplifier. I'm not afraid to show my work, and I am a rank amateur. I'm not trying to be a jerk about it, I just think fair is fair. To answer a bit out of order, I didn't call Justin out at all. He has made a point of saying how meticulous his work is and, since he is trying to promote his products, it's always nice to show the world that the claim is justified. His pictures bear out the care that he is taking in constructing his amps. This is not a new marketing concept as many equipment manufacturers include under-chassis pictures on their web sites and in promotional materials. I've shown pictures of beautifully constructed amps and other electronic gear to non-technical folks and they often comment about how neat and organized everything looks in spite of having no idea what they are looking at. The reason I don't post pictures of my "products" is that I don't have any for sale. Being retired (from the business/monetary standpoint) I now offer prototype services to local audiophiles. So, for example, if someone called me and said "Maynard, I want to experience the sound of a flea powered SET with my CWs. What can you do for me?" I would either bring over a prototype (if I happened to have one on hand), or build one (at my own expense) for the person to try. This is without obligation to the person involved. Basically, if a concept appeals to me, I'll design and build it for fun. If the person likes what he hears and wants to keep it, he may offer me something on trade, offer to replace all the parts which I used, ask me to build an identical amp in some other kind of enclosure (I use a plain aluminum chassis when prototyping), and so on. I'm not interested in making any money on this, and refuse to take anything for my time and effort. My "profit" is seeing the look of sheer joy on the person's face the first time they experience their favorite music through the "musical instrument" which I have created for them. The same goes for my work in vintage amp and antique radio restoration. In the latter two cases, I'll either do the work gratis (if it isn't too costly), or simply give the person a list of the parts needed and where to buy them (or sit down at the computer with them, make up the order, and let them pay for it!) When they have everything, they give the parts to me and I do the job. The amp and radio work is my way of preserving history. Making a 70 year old radio play as it did when new (and many times even better with some circuit modification), or a 50 year old amp deliver a whole new level of musical enjoyment is my return. So, there it is! I don't normally photograph my creations (no point- I know what they look like ), but have attached a couple of a recently prototyped SET. The guy was quite specific about what he wanted- absolutely no audible hum with his ear against the speaker grille, no hiss if at all possible, cheap and abundant tubes, good bass, and very smooth highs. This was a nice challenge which appealed to me. It required using a separate power supply and runs very highly filtered DC for everything, including the filaments, and a circuit which is simplicity itself. He is extremely happy! Maynard 3 Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted February 10, 2014 Share Posted February 10, 2014 I found a couple of articles which drive home the point I made about the need to show off meticulous construction if it is present. In both of the following, look at the under-chassis photos and read down a bit for the description. Both of these units are in the $5k price range!!! http://www.stereophile.com/content/sophia-electric-91-01-300b-monoblock-power-amplifier http://www.stereophile.com/content/listening-133-page-2 Maynard Quote Link to comment Share on other sites More sharing options...
Cornman Posted February 11, 2014 Share Posted February 11, 2014 I found a couple of articles which drive home the point I made about the need to show off meticulous construction if it is present. In both of the following, look at the under-chassis photos and read down a bit for the description. Both of these units are in the $5k price range!!! http://www.stereophile.com/content/sophia-electric-91-01-300b-monoblock-power-amplifier http://www.stereophile.com/content/listening-133-page-2 Maynard I found a couple of articles which drive home the point I made about the need to show off meticulous construction if it is present. In both of the following, look at the under-chassis photos and read down a bit for the description. Both of these units are in the $5k price range!!! http://www.stereophile.com/content/sophia-electric-91-01-300b-monoblock-power-amplifier http://www.stereophile.com/content/listening-133-page-2 Maynard I found a couple of articles which drive home the point I made about the need to show off meticulous construction if it is present. In both of the following, look at the under-chassis photos and read down a bit for the description. Both of these units are in the $5k price range!!! http://www.stereophile.com/content/sophia-electric-91-01-300b-monoblock-power-amplifier http://www.stereophile.com/content/listening-133-page-2 Maynard I found a couple of articles which drive home the point I made about the need to show off meticulous construction if it is present. In both of the following, look at the under-chassis photos and read down a bit for the description. Both of these units are in the $5k price range!!! http://www.stereophile.com/content/sophia-electric-91-01-300b-monoblock-power-amplifier http://www.stereophile.com/content/listening-133-page-2 Maynard Hi Maynard, I have enjoyed your post's & own the Sophia mentioned in this post. I use it only on the K402 horns with Tad 4002. I am curious if you have ever heard thhese mono blocks & if so whats your opinion of them & which of your amps would you recommend for this application? Quote Link to comment Share on other sites More sharing options...
Cornman Posted February 11, 2014 Share Posted February 11, 2014 Sorry about the mutiple quotes above dont know how that happned, also intended to send this as a pm. Sorry. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 11, 2014 Share Posted February 11, 2014 Hi Maynard, I have enjoyed your post's & own the Sophia mentioned in this post. I use it only on the K402 horns with Tad 4002. I am curious if you have ever heard thhese mono blocks & if so whats your opinion of them & which of your amps would you recommend for this application? He was pointing out the terrible layout of the Sophia amplifier in that link. So I would doubt he will give any opinions with regards to the Sophia. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 11, 2014 Share Posted February 11, 2014 (edited) To answer a bit out of order, I didn't call Justin out at all. I feel I am the one a bit out of order here. I more than likely read into things wrong to where you didn't call him out...you just merely asked. My bad... Thanks for posting images of that amp and power supply. You do excellent work...all nice and symmetrical and such...awesome! This way other forum members can see your work, and the skill involved. I'm not going to ask about the circuit involved, for I feel I should not ask...but, you think those big ol' Hammonds are large enough for that circuit? Mike Edited February 11, 2014 by mike stehr Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted February 11, 2014 Share Posted February 11, 2014 Cornman, regarding the 4002 and Sophia I haven't heard either, so I couldn't even begin to speculate in any way. As far as other amps go (mine or others), it's impossible to say what might work well or not. I prefer doing my amp stuff locally so I have access to the systems in which they are used. That way, if someone wants to modify the sound in some fashion, I can make changes which they can audition on the spot. It then becomes easy to make the changes permanent. And, as Mike pointed out, that link was intended to show that even costly equipment isn't always built to a level of quality which one would expect. Looking at the Sophia, one can appreciate Justin's efforts even more given his far lower price points. Mike, I'd be the last person to claim that I have never misunderstood another forum member's comments!!! Drop me a note any time if you want to discuss circuits. Nothing I do is proprietary by any means. If I can convince Amy and Chad to set up a DIY amp section on here (I've tried!), I'll gladly post schematics of various things which the experimenters on here may find of interest. Maynard Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted February 11, 2014 Share Posted February 11, 2014 FWIW, I did own a Sophia. When they first came out. I thought it sounded distorted and created a nasty edge to vocals and violins. A kind of serrated edge that wasn't natural. I investigated only because I could. I found a very unstable design which wanted to oscillate, and so it was heavily compensated with some brute force filters to keep it stable. This cause a nasty case of ringing. The OPTs seemed to be incapable of much clean HF response. All in all, I thought that it was a bad value. For that kind of money someone could buy a SS amp that worked a lot better. YMMV. THAT"S JUST MY OPINION. Mark, take a look at Atkinson's measurements on the Sophia. He got some really wild results initially due to an atypical grounding arrangement. Might explain some of what you encountered. And, Mike, I forgot to address your comment about those Hammond monsters. The guy insisted on going for the best possible bottom end. Personally, I would have used the 125ESE. But, why argue? I had the opts on hand from another project so I didn't have to lay out any $$$ to use them. I found one picture, from about a year ago, of some of the prototypes which populate every room of the house, and have attached it. Some of them now live elsewhere! My wife is still threatening to throw me out, amps and all. Quote Link to comment Share on other sites More sharing options...
Cornman Posted February 13, 2014 Share Posted February 13, 2014 Guy's I fully agree with you the build quality of some of these Asian amps are no where near that of our American cottage builders that we are so fortunate to have here on the forum. But one correction to start with is the Sophia is not a $5K amp as stated above. I purchased mine for well under $3K new with the Princess tubes. I will be the first to admit this was an impulse buy an probably would not have done so had I researched the company a little more. With that said This amp to my ears has out performed all contenders so far. Surprise surprise. Will also be the first to agree perhaps that's how bad my hearing or interpretation of quality of sound is.Mark, which model of Sophia did you try? I dont doubt any of you builders opinions, thats why I am reaching out to you, to show me or recommend a better product , I am willing to commission a build or pay for a trial (as I did with the First Watt F3) from Mdeneen ,Nos, Maynard, Eric,or Justin. So at this point to to call one book better based on it's cover I can not except. The sound speaks for itself. I will start a new thread - Calling on all builders & designers What would you build or use for the Jubilee? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 13, 2014 Share Posted February 13, 2014 Cornman, it you don't find the amplifiers objectionable sounding, then I wouldn't be too concerned. Unless you have a hankering desire for something better. I take it you are using the Sophia amplifiers with the K402/Tad driver combination... Do the amplifiers have the same characteristics to your ears in relation to what Mark explained in his post? Hard edgy serrated sound on vocals/violin, a ringy/zingy overall kind of characteristic? I think the review article linked may have hinted towards these anomalies, but they were being nice. Maybe they corrected the problems over time... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 13, 2014 Share Posted February 13, 2014 (edited) And, Mike, I forgot to address your comment about those Hammond monsters. The guy insisted on going for the best possible bottom end. Personally, I would have used the 125ESE. But, why argue? I had the opts on hand from another project so I didn't have to lay out any $$$ to use them. I found one picture, from about a year ago, of some of the prototypes which populate every room of the house, and have attached it. Some of them now live elsewhere! My wife is still threatening to throw me out, amps and all. Well, you better listen to your Wife. Unless you want to build a little house made of tube amplifiers or something... Edited February 13, 2014 by mike stehr Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted February 13, 2014 Share Posted February 13, 2014 (edited) "It's very different than a "good preamp". Of course these are opinions, and I am just giving you one opinion. Preamps have an important imprint on the sound and the range of sonic differences among preamps is staggering. If you are appreciating the difference in sound between your SS amp, and your new tube amp, imagine if you will the same or larger difference to be heard between a SS preamp and a tube preamp. It's huge. It's at least as significant as the difference you are hearing in amps. I think in another thread you were talking about small differences and whether you would chase them or not and so on. I am only commenting here because this computer versus tube preamp sort of thing, is the kind of small difference that people do chase." How about the difference between a Pre-amp and no-pre-amp at all. Can a Pre-amp improve the sound (Other than just increased gain) over no pre-amp at all? And can you give an example of how ? Thanks Edited February 13, 2014 by Cut-Throat Quote Link to comment Share on other sites More sharing options...
Cornman Posted February 13, 2014 Share Posted February 13, 2014 Cornman, it you don't find the amplifiers objectionable sounding, then I wouldn't be too concerned. Unless you have a hankering desire for something better. I take it you are using the Sophia amplifiers with the K402/Tad driver combination... Do the amplifiers have the same characteristics to your ears in relation to what Mark explained in his post? Hard edgy serrated sound on vocals/violin, a ringy/zingy overall kind of characteristic? I think the review article linked may have hinted towards these anomalies, but they were being nice. Maybe they corrected the problems over time... No, my Sophia have none of these characteristics. Rereading Art Dudley review, I can on agree with his conclusion- " Conclusions "Richness, immediacy, and just enough punch. Very slight lack of sparkle and mid-treble openness on some records, strangely too much texture on others. Consistently enjoyable, engaging, and fun. Paint smell hasn't gone away yet." Thus read the last lines of my listening notes: as good a place as any to begin my ending. Why spend more? Well, there's still more to be had—for more money, of course—and, if your system and/or your listening style demand more openness, the Sophia Electric 91-01 300Bs might not be for you. Then again, for those who crave richness, color, and presence above all else, the 91-01s are hard to beat for the price. A very good-sounding amplifier: not the best built, and not the rarest or most exotic, but a solidly musical, sumptuously colorful amp that's loaded with the sort of performance for which the classic 300B tube is rightly known. Recommended." I am definitely not saying they are the best,only the best I have heard so far. But I know (hear) enough to know there can be better, & probably not at a higher cost. And yes Mike like most of us I have a hankering desire for something better. Thats pretty common for most us that have gone this deeply into this hobby. I woud love to have any one of you old pros over here to hear & give your opinion of this sound I am sure there are issues I am just can not adequately describe or recognize some of these nuisances, & better yet introduce me to an-amp that I like better. For that reason I am starting a new thread Asking for that help from you builders & Jub owners as well. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted February 13, 2014 Share Posted February 13, 2014 How about the difference between a Pre-amp and no-pre-amp at all. Can a Pre-amp improve the sound (Other than just increased gain) over no pre-amp at all? And can you give an example of how ? Thanks The more electronics you put into the signal chain the greater the potential for sonic degradation. All preamps have power supplies which can add noise. Tube type preamps, by their nature, can add noise from the electron flow through the tubes themselves. Then there's the issue of shared power supply rails in the preamp causing a loss of channel separation (this has been discussed in detail in other threads of not that long ago.) No preamp at all is always the clear winner in my experience. As long as the input sensitivity of the amp is low enough so that it can be driven to full output by the source component, a passive line stage between the source and amp is the way to go. If you're handy, this can be a really cheap experiment to try on your own (I'm talking around $25.) A couple of pots, resistors, a few rca jacks, and metal enclosure of some kind is all it would take. Maynard Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 13, 2014 Share Posted February 13, 2014 (edited) Can a Pre-amp improve the sound (Other than just increased gain) over no pre-amp at all? And can you give an example of how ? Thanks Yes anytime the source componet can't supply the voltage/current needed to properly drive the input impedance of a given amplifier. This can manifest itself in several ways such as a perceived lack of bass, rolled off highs and (for lack of a better way to describe the effect) a slower pace to the performance. When source componets and amplifiers match up properly a passive switcher/level control componet can challenge or exceed high quality multi-thousand dollar pre-amps in my experience and often with systems using high sensitivity loudspeaker systems such as Klipschorns the lack of gain with a passive switcher/level control componet gives a better noise floor for the total system. miketn Edited February 13, 2014 by mikebse2a3 Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted February 14, 2014 Share Posted February 14, 2014 How about the difference between a Pre-amp and no-pre-amp at all. Can a Pre-amp improve the sound (Other than just increased gain) over no pre-amp at all? And can you give an example of how ? Thanks Of course to play LPs you will need a preamp, there's no choice. As to connecting a source direct to a power amp, there's several possibilities. If the source has a VC already, and enough gain, and is low enough impedance, then that's a good bet to plug directly to the amp. But, if there is no VC on the source, and you just hang a passive VC on the source with cables going to the amp, you can get some rolloff and some added noise. I rarely find that a passive preamp (oxymoron, really) is very useful. So, as to the question, my answer is sometimes yes, sometimes no. Mark, In my case I am not using any LPs. And I always use a tube DAC which my digital sources are fed, which has a volume control. So what are your comments in lieu of this. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted February 14, 2014 Share Posted February 14, 2014 BTW, do you still have the Tektons? Yes, I still have the Tektons. They are in my Shop area that I listen to when building stuff. --- Thanks for turning me on to them. I use a Eastern Electric Minimax Tube Dac with Volume Control. I am bi-amping with SET Amps (45 or 2A3) on the Tweets and Horns. And Hypex Plate Amps on the Bass Bins. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 14, 2014 Share Posted February 14, 2014 Eastern Electric Minimax DAC SpecificationsFrequency Response : 15Hz – 32KHzSampling rates : 32bit 32KHz 44.1KHz 48KHz 192KHz (except USB)Dynamic Range : 129dBDigital Input Impedance : 75 ohmOutput Impedance : Tube 22KSolid State 10KOutput Voltage : Tube 3V +- 0.5dBSolid State 2.5V +-0.5dBS/N ratio : Tube 90dBSolid Sate 95dBTHD : 0.5%(Tube) 0.02%(Solid State)Dynamic Range : 129dBPower Consumption : 12WMain Voltage : 120V, 230V, 240V switchableG.W. : 4.3kgsN.W. : 3kgs Cut-Throat this unit's output impedance is on the high side and thus has potential interaction issues depending on which output option you are using when driving input impedances in the commonly seen 20k to 100k range. This doesn't mean someone wouldn't like the sound but they should be aware of the possibilities. I like to see a minimum of something around a 1:10 ratio between output to input impedances to minimize negative interactions. miketn Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted February 14, 2014 Share Posted February 14, 2014 BTW, do you still have the Tektons? Yes, I still have the Tektons. They are in my Shop area that I listen to when building stuff. --- Thanks for turning me on to them. I use a Eastern Electric Minimax Tube Dac with Volume Control. I am bi-amping with SET Amps (45 or 2A3) on the Tweets and Horns. And Hypex Plate Amps on the Bass Bins. I was at Eric's site earlier today, and he is no longer making any single driver designs, only 2-way. Argh! Naturally, I sold mine when we moved and now I wish I had them back. Your DAC has some interesting specs as shown by Mike. What crossover do you use? Well, I have 2 crossovers. One is the active crossover that is built into the Hypex Amps. This is between the Bass Bins and the Horns. Then I use a Modified Type 'A' section between the Horns and Tweeters. BTW - If you call up Eric, he would probably build you a single driver speaker. He did some custom work for me that was un-related to his standard line of products. Quote Link to comment Share on other sites More sharing options...
justinsweber Posted February 14, 2014 Share Posted February 14, 2014 Guy's I fully agree with you the build quality of some of these Asian amps are no where near that of our American cottage builders that we are so fortunate to have here on the forum. But one correction to start with is the Sophia is not a $5K amp as stated above. I purchased mine for well under $3K new with the Princess tubes. I will be the first to admit this was an impulse buy an probably would not have done so had I researched the company a little more. With that said This amp to my ears has out performed all contenders so far. Surprise surprise. Will also be the first to agree perhaps that's how bad my hearing or interpretation of quality of sound is.Mark, which model of Sophia did you try? I dont doubt any of you builders opinions, thats why I am reaching out to you, to show me or recommend a better product , I am willing to commission a build or pay for a trial (as I did with the First Watt F3) from Mdeneen ,Nos, Maynard, Eric,or Justin. So at this point to to call one book better based on it's cover I can not except. The sound speaks for itself. I will start a new thread - Calling on all builders & designers What would you build or use for the Jubilee? Your question is a complex one. How many Jub owners are using passive crossovers. If passives are used, then a single amp is a great choice. But as I assume most Jub owners are running actives, I think a SS amp in the 50watt high current variety or 300watt AB (Like from emotive) would be my choice for bottom end and Single ended (any variation) would be my choice for the top end. (I generally like my sound more rolled and relaxed so a SE amp would give me the lush sound I’m after. If the buyer wanted a faster more taught sound, P-P tubes would be my recommendation. I think the Top Hats sound best with tubes… but that’s me. Among SE amps I’ve built or heard and enjoyed. 1626 Darling circuit… So my favorite if you want warmth. .75watts (NOS BABY!) 6L6 SE (No feedback, massive power supply) ran off an ipod. 3watts RCA circuit SE EL-84 no feedback (RCA manual) NOS Tubes (RCA of course). Easy to drive. 6B4G SE no feedback, massive power supply, NOS tubes (If I only could afford NOS for every tube). Easy to drive… benefited from pre. Built 8 so far…2 as 300b variations. Not in love with the 300b but it could have been the EH300b that I took issue with… Didn’t seem better than the 6B4G but had added cost. (No I didn’t need the extra 3watts). J. 6L6/KT88 SE (mild feedback, UL, massive power supply). This is my all around choice… 6l6s from more midrange bloom and KT88s if you want more authority/grunt. 6T9 from Tom McNally… can’t get this tube any more… but was pretty amazing. 6LU8 UL build and had several of these… can be very quite and tubes are inexpensive, but not nearly as sweet a sound as 6T9. Chinese 845SE Way cool, too complex for me. Chinese 6V6SE.. I didn’t like the low end extension, but that was transformers. I love the 6V6 sound… little more lush than el84 and more rolled, but just not wanted by buyers. Quote Link to comment Share on other sites More sharing options...
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