bassowl Posted August 4, 2021 Posted August 4, 2021 Hello SNAers, I'm looking for some opinions on where I should go with my system particularly in the case of my amplifier choices going forward. I currently have Technics SL-23 / Schiit Modi Multibit -> Rotel RC-1550 -> Transcendent OTL 1.5W -> Polk 11t I'm currently using the Transcendent just as an intro to tube sounds but obviously it doesn't go too loud before breaking up (the Polks sensitivity is 95db). I definitely do like what I've heard so far but I feel the expense will be too high to get a tube power amp with more power. If I sell off all the spare gear I have, I might be able to scrape around $1200 (transcendent included). Would you recommend putting the money into a DIY tube amp of some kind with more wattage seeing as I like the sound (I can solder and have built a few guitar pedals before and done basic component replacements etc) or put that money into finding a matching Rotel power amp (RB-1550) or similar? Should I avoid the valve rabbit hole at that price point? What would you do? 1
Quark Posted August 4, 2021 Posted August 4, 2021 (edited) Perhaps sell off the Rotel as well and see if you can stretch to a Consonance M100+. The Consonance is a great sounding little valve amp the punches way above its price point and sounds like a lot more than it's modest 40W output. Edited August 4, 2021 by Quark 4
bassowl Posted August 4, 2021 Author Posted August 4, 2021 Thanks very much for your thoughts, Quark I'll take a look at that one! 1
RCAJack Posted August 4, 2021 Posted August 4, 2021 The Transcendent’s low power and topology are so unusual, it seems like a real edge case even in the tube realm. Have you ever tried any other amps with the Polks? A quick search says they’re 90dB/6 ohms so I’d expect any mainstream solid state amp to drive them to decent levels. A 15W amp should go twice as loud as the little Transcendent, other things being equal, and there are push-pull EL84 tube amps and kits that would do that for around your budget. Loud, tight, powerful bass not their strength as a rule. Personally I’d have to start with a demo to help decide what kind of amp will suit my music and volume preferences best with speakers I’m into. 1
bassowl Posted August 4, 2021 Author Posted August 4, 2021 1 hour ago, RCAJack said: The Transcendent’s low power and topology are so unusual, it seems like a real edge case even in the tube realm. Have you ever tried any other amps with the Polks? A quick search says they’re 90dB/6 ohms so I’d expect any mainstream solid state amp to drive them to decent levels. I've also had them hooked up to a Marantz Model 140 and Acurus A100X3 which both pushed the Polks loud enough, but I guess I don't feel super attached to either of them (or the Transcendent for that matter). Perhaps I just need to go and listen to some new gear instead of trying to make something amazing work out of (probably) mismatched vintage/secondhand stuff 1
knotscott Posted August 5, 2021 Posted August 5, 2021 (edited) Bassowl - I say leap into that rabbit hole, especially since you like what you've heard! I love the clarity, resolution, and 3D soundstage of tubes, and in my nearly 40 years of audio exposure to some really nice gear, I haven't heard an SS amp that sucks me into the recording like good tube gear does. Plus you can fine tune the sound to your liking by tube rolling....it's not only fun, but its useful to customize the sound just the way you like it. There's a downside with cost and heat (there are plenty of good bargains if you look), and there's a learning curve, but it's well rewarded in the end with a great foundation for a high res system that'll not only warm your heart when you listen, but are pretty darn cool to watch glow in the dark! I'd hate to see someone miss the opportunity to build an amazing system around their tube gear....it's been a very rewarding journey for me. I'm driving 89db speakers with a pair of old Dyna/VTA 70 tube amps (20wpc triode/35wpc ultralinear).....99% of the time I prefer the 20wpc triode mode. It's plenty loud for me, but it's a matter of preference. Willsenton and Reisong are a couple of the more affordable Chinese made tube amps that get really good reviews. Edited August 6, 2021 by knotscott 5 1
bassowl Posted August 6, 2021 Author Posted August 6, 2021 Thanks @knotscott I do love the sound and as I'm not attached to the ss amps I have I think I'm leaning towards heading down that road 1 1
robmid Posted August 7, 2021 Posted August 7, 2021 On 04/08/2021 at 12:40 PM, bassowl said: Hello SNAers, I'm looking for some opinions on where I should go with my system particularly in the case of my amplifier choices going forward. I currently have Technics SL-23 / Schiit Modi Multibit -> Rotel RC-1550 -> Transcendent OTL 1.5W -> Polk 11t I'm currently using the Transcendent just as an intro to tube sounds but obviously it doesn't go too loud before breaking up (the Polks sensitivity is 95db). I definitely do like what I've heard so far but I feel the expense will be too high to get a tube power amp with more power. If I sell off all the spare gear I have, I might be able to scrape around $1200 (transcendent included). Would you recommend putting the money into a DIY tube amp of some kind with more wattage seeing as I like the sound (I can solder and have built a few guitar pedals before and done basic component replacements etc) or put that money into finding a matching Rotel power amp (RB-1550) or similar? Should I avoid the valve rabbit hole at that price point? What would you do? Transcendent Sound Son of Beast with the Grounded Grid would do the trick. OTL's are magic...as long as they are well ventilated and valves don't blow. 1
RoHo Posted August 7, 2021 Posted August 7, 2021 On 04/08/2021 at 1:28 PM, Quark said: Perhaps sell off the Rotel as well and see if you can stretch to a Consonance M100+. The Consonance is a great sounding little valve amp the punches way above its price point and sounds like a lot more than it's modest 40W output. A great suggestion and I would doubly suggest that an integrated valve amp, which is really only a power amp with a volume control, is good idea. Your Rotel Pre-amp is then redundant and can be sold and anyway it probably wouldn’t add anything if teamed with a valve power amp. Consonance is a well established brand and excellent value for money. 1
bassowl Posted August 7, 2021 Author Posted August 7, 2021 Haha, fine! You all leave me no choice but to sell all my stuff then and see what budget I have to play with to get something nice and tube-y! 1
almikel Posted August 8, 2021 Posted August 8, 2021 On 04/08/2021 at 12:40 PM, bassowl said: Would you recommend putting the money into a DIY tube amp of some kind with more wattage seeing as I like the sound (I can solder and have built a few guitar pedals before and done basic component replacements etc) I would be very cautious before treading down the DIY tube amp path - the voltages running around inside a tube amp chassis are lethal - to quote Doug Marcaida from "Forged in Fire "it will kill"... On 04/08/2021 at 12:40 PM, bassowl said: I can solder and have built a few guitar pedals before and done basic component replacements etc At some stage through the DIY process of building a tube amp you will need to test the amp with the power on - with voltages normally higher than mains voltage - that's such a different ball game than soldering and building guitar pedals...please be extraordinarily careful...and if you've never mucked with mains power before - don't! By all means experiment with tube power amps - but as a beginner, be very cautious of DIY that involves mains power. On 06/08/2021 at 5:17 AM, knotscott said: There's a downside with cost and heat Most tube amps I've come across tend to be biased to class A operation (all output devices managing the entire signal) - including push/pull tube designs. Class A amps always generate loads of heat. All single ended amps are always class A (tube or solid state) - push/pull amps can be class A (all output devices manage the entire signal), class B (1 of the output devices operates while the other is off), class A/B (2nd output device is turned on a bit - most solid state amps), or class D (output stage is like class B - only one side is turned on at a time, but the input stage of the amp is not analog) In my non airconditioned room in Brisbane class A amps aren't suitable in summer - Perth may be different... I ran 2 x 10W class A single ended monoblock transistor amps driving my tweeters in my setup for a while...my God they ran hot - added way too much heat for Brisbane summers, but nice heaters in Brisbane's frigid winters cheers, Mike 2 1
Third Time Lucky Posted August 8, 2021 Posted August 8, 2021 A Weston amp would be a nice little addition and their 30w EL34 offering is $2300. The Consonance great Osborn sells is priced amazingly but this way you are supporting local manufacturing.
bassowl Posted August 8, 2021 Author Posted August 8, 2021 6 hours ago, almikel said: I would be very cautious before treading down the DIY tube amp path - the voltages running around inside a tube amp chassis are lethal - to quote Doug Marcaida from "Forged in Fire "it will kill"... At some stage through the DIY process of building a tube amp you will need to test the amp with the power on - with voltages normally higher than mains voltage - that's such a different ball game than soldering and building guitar pedals...please be extraordinarily careful...and if you've never mucked with mains power before - don't! By all means experiment with tube power amps - but as a beginner, be very cautious of DIY that involves mains power. Gotcha, point taken - probably won't do this, then - PLUS wearing insulated gloves would make soldering so much harder! 6 hours ago, almikel said: In my non airconditioned room in Brisbane class A amps aren't suitable in summer - Perth may be different... I ran 2 x 10W class A single ended monoblock transistor amps driving my tweeters in my setup for a while...my God they ran hot - added way too much heat for Brisbane summers, but nice heaters in Brisbane's frigid winters Hmm I think I really need to do some reading on the different 'classes' of amps to understand all you said, TBH. Also noted that I need to buy a summer and winter amp. Or upgrade my aircon 4 hours ago, Third Time Lucky said: A Weston amp would be a nice little addition and their 30w EL34 offering is $2300. The Consonance great Osborn sells is priced amazingly but this way you are supporting local manufacturing. This will go on my list to research whilst I gather funds, thanks for the tip! 1
almikel Posted August 10, 2021 Posted August 10, 2021 On 09/08/2021 at 12:18 AM, bassowl said: Hmm I think I really need to do some reading on the different 'classes' of amps to understand all you said, TBH. The "class" is about the "biasing" of the devices in the output stage - ie how much they're turned on with no input signal. Class "A" means all output devices are turned on constantly - which means lots of heat to dissipate By definition any single ended amplifier must be class A - the output stage devices are biased to be fully turned on so that any input signal (+ve or -ve) will be amplified at the output. With no input signal the output device is still conducting max current. You could also design a "push/pull" output stage to be biased in class A - both devices conducting all the time - most tube push/pull amps I've come across are class A. Class "B" only applies to "push/pull" output stages - where one output device is on while the other device is off - "crossover" distortion in the region where 1 device turns on and the other device turns off is an issue. Negative feedback is typically used in the amplifier design to reduce this distortion. Douglas Self is a proponent of this design topology - but commercial designs are rare Interestingly class "D" amps use class "B" operation of their output stage...ie 1 device on, one device off Class A/B is the most typical topology for "push/pull" solid state power amps - in between class A and class B. At no signal both devices have some level of bias current to keep them "slightly" turned on A +ve swing input is amplified by the +ve output stage A -ve swing input is amplified by the -ve output stage Crossover distortion is manage via negative feedback Class A/B runs much cooler than class A Class D - sometimes called "Digital" amps - although some people here on SNA dislike this terminology...I'm not sure why...the output stage of the amp is fed from my perspective a digital signal... Essentially the analog input signal is sampled very fast (Megahertz speed) to produce a Pulse Width Modulated (PWM) / Pulse Density Modulated (PDM) signal which is fed to the output devices, then the output signal goes through a low pass filter to leave the amplified audio signal. Those that don't like the term "digital" amp may prefer the term "switching" amp... Class D run cooler than class A/B cheers Mike 2
bassowl Posted August 10, 2021 Author Posted August 10, 2021 So the advantage then of a class A is that there is no crossover distortion as there's only one output device. So would I be correct in assuming any other class will have crossover distortion and that will change as components age and drift out of tolerance? Thanks so much for taking the time to write all that out, Mike, it's very interesting - I think I'll read up a bit about how the negative feedback part works.
almikel Posted August 18, 2021 Posted August 18, 2021 On 10/08/2021 at 11:02 PM, bassowl said: So the advantage then of a class A is that there is no crossover distortion as there's only one output device. A single ended amp has to be class A - and has no crossover distortion...but potentially other distortions... An amplifier operating in "class A" doesn't have to be single ended - it could be single ended or push/pull - both single ended and push/pull amp topologies can operate in "class A" - ie the output devices are biased to conduct all the time...but an amp with a single output device must be class A. "Back in the day" when all amps used valves (1950s/1960s), amplifier power was small, and everything was class A only - single ended amps were regarded as "lo fi" - all the decent amps were "push/pull" (Quad, McIntosh etc). Fast forward many decades and single ended amps are popular again - esp single ended SET valve amps...if you like their sound, and can achieve your SPL (loudness) requirements - fill your boots... ...single ended "class A" SET valve amps tend to max out around 10W output or less - you need extraordinarily efficient speakers to hit "reasonable" SPL (volume) "in room" with only 10W or so to play with. Coming back to class A irrespective of valve/solid state or single ended/push pull - they run hot - as in "add significant heat to your room". By design class A is around 25% efficient - the rest heats your room. I ran some nice sounding class A 10W single ended transistor amps for a while on my tweeters, but they clipped all the time so I swapped them out... ...they sounded lovely below clipping but jeez they ran hot - way too hot for a Brisbane room without air con... I run a 3 way active + single sub setup - all my amps are class A/B solid state. The amp heatsinks rarely get above ambient temperature. Running class A just doesn't work in Brisbane summers - likely not much better in Perth. cheers, Mike
almikel Posted August 20, 2021 Posted August 20, 2021 On 10/08/2021 at 11:02 PM, bassowl said: So would I be correct in assuming any other class will have crossover distortion and that will change as components age and drift out of tolerance? In simple terms the answer is yes - and even push/pull class A amps will likely have some level of crossover distortion - how much distortion and how high the "order" of the distortion comes down to amp design. It's generally agreed that amplifier distortion at higher "orders" is bad (with increasing "badness" as the "order" increases if amplitude stays the same)... ...but wtf is the "order" of the distortion? Apologies if any of the below is "sucking eggs"... All amps have distortion - that's a given. All amps have harmonic distortion - that's where the "order" comes in - most amps spec their Total Harmonic Distortion (THD) - some combination of all orders of distortion - not necessarily a good indicator of how the amp "sounds". Say you play a 250Hz sine wave through your stereo - that's the fundamental frequency. Your amplifier will amplify that 250Hz sine wave and send it to your speakers - as expected - that's what amplifiers do. Depending on the topology and design of your amp, your amp will also send harmonics of that fundamental frequency to your speakers - but at significantly lower levels than the amplified fundamental frequency: 2nd harmonic is 2 x 250Hz = 500Hz (2nd order distortion) 3rd harmonic is 3 x 250Hz = 750Hz (3rd order distortion) 4th harmonic is 4 x 250Hz = 1kHz (4th order distortion) 5th harmonic is 5 x 250Hz = 1.25kHz (5th order distortion) etc Every amplifier will have some amount of harmonic distortion at every harmonic (theoretically), but with good design the distortion (hopefully quickly) drops below the noise floor. The application of global negative feedback in amplifier design to reduce distortion is a whole topic on it's own - but generally in solid state amp design, some level of global negative feedback is used. The topology of the amplifier (eg single ended vs push/pull) will have an impact on the prominence of even order harmonic distortion vs odd order harmonic distortion. A single ended topology tends towards even order harmonic distortions and a push/pull topology tends towards odd order distortions. Qualitatively even order distortions are considered "warm/muddy" and odd order distortions are considered "edgy/harsh" - choose your distortion! The above is enough information overload, so I'll park amplifier Intermodulation Distortion (IMD) for the moment...esp based on my comment below: In the scheme of things, unless your amplifier is terrible (very unlikely) then: your speakers, the placement of your speakers in your room, and the room itself Will contribute to your "in room" sound vastly more than any part of your electronics chain excluding EQ. EQ when appropriately applied is the "icing on the cake" for managing "in room" bass when the bass is "reasonably" under control with treatment and a lightly constructed room (where low bass leaks out). Mike 1 1
Ihearmusic Posted August 20, 2021 Posted August 20, 2021 If you are serious about a tube amp in your system, I could come and demo a MingDa MC34-A at your place. I am an Authorized MingDa dealer without the rip off price. http://undergroundsoundaudio.com/SHOP/index.php/;focus=HSTPTP_cm4all_com_widgets_Shop_7128726&path=?subAction=showProduct&categoryId=35843&productId=144917#HSTPTP_cm4all_com_widgets_Shop_7128726 That is the only way you find out what it sounds like in your environment. Everything else is just talk and confusing. Stephan 4
bassowl Posted August 21, 2021 Author Posted August 21, 2021 23 hours ago, almikel said: In the scheme of things, unless your amplifier is terrible (very unlikely) then: your speakers, the placement of your speakers in your room, and the room itself Will contribute to your "in room" sound vastly more than any part of your electronics chain excluding EQ. EQ when appropriately applied is the "icing on the cake" for managing "in room" bass when the bass is "reasonably" under control with treatment and a lightly constructed room (where low bass leaks out). Thanks! A great explainer of harmonic distortion! My room is untreated but it is something I should look into by the looks. 22 hours ago, Ihearmusic said: If you are serious about a tube amp in your system, I could come and demo a MingDa MC34-A at your place. I am an Authorized MingDa dealer without the rip off price. Stephan that is very generous and I think I will take you up on that offer. 2
Ihearmusic Posted August 22, 2021 Posted August 22, 2021 21 hours ago, bassowl said: Stephan that is very generous and I think I will take you up on that offer. No worries. Just send me a PM with you details and we take it from there. Stephan 1
muon* Posted August 22, 2021 Posted August 22, 2021 Yes, your MingDa amps are well priced! I liked the little MingDa MC-34B a friend had. 1
dannyngx Posted August 26, 2021 Posted August 26, 2021 If you're not in a hurry and opposed to buying used, maybe watch the classifieds as well. Gives you an cheaper entry point just in case you don't like the sound. I got both of my tube amps from here, and great experience with both (one of which is the aforementioned Consonance m100+). Lucky you're in Perth and can demo gears. I'm in Melbourne and forever in lockdown! Another suggestion as well is the Elekit self-assembled amp kits. They seem to have good reputation, but I'm not sure on pricing.
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