captainbeefheart

I just looked at those Dayton data sheets and they appear to be more lossy compared to the Sonicaps, they state a DF of .1% which is on the high side for a polypropylene. The ESR measured by Dean for the 2uF Sonicap roughly worked out to a DF of .0125% which means it's a really high quality capacitor. Those Daytons are probably a nice middle ground between the flat yellow Tecate with a DF of .5% and a Sonicap of .0125%

You can't go by if the capacitors are physically leaking or not, you want to test the ESR to see if they have increased too far and become too lossy. I recommend getting the flat yellows from Dean or in my opinion the best is paper in oil.

Don't bother with the other tests. That's enough information to know that the ESR is quite different between the two dielectrics. That's roughly a DF of .0125% which is excellent. .01 ohms vs .47 ohms will give different results in regard to losses. The real question is how much of this is audible and until we get some blind tests going it's just a fun conversation. People do report their listening results but I have a hard time swallowing these sorts of reviews, I don't trust my own ears unless the sound is significantly different. If I have to question if I hear a difference at all then I probably don't.

Those Tecate caps are showing a DF of .5% Since a polypropylene will be less than .1% and often probably closer to .05% that's a magnitude of 10x difference. A polypropylene should measure ESR at 1kHz of around .039 ohms compared to the polyester .47 ohms. That's of course not taking into consideration the inductance of the capacitor so the reading on the meter may be slightly higher at .045 ohms ESR. C= 2uF At 500mA of current the ESR losses will be 250mV for the Mylar and 20mV for the Polypropylene.

Bypassing capacitors is for applications where you need a very large value of capacitance and so Aluminum Electrolytic types are chosen for their small size and cost. If the application requires low impedance up into RF spectrum then one would bypass the electrolytic with a small high quality film cap to reduce impedance up into RF spectrum.

Dean do you have a 2uF Polypropylene you can test at 1kHz? Can you test at 10kHz and 20kHz also? Get a heat gun or freeze spray and watch ESR change as you heat/cool the mylar capacitors while watching the meter. Not really no. In a perfect world a capacitor is a capacitor and they are all the same, in the real world that's not true and why we discuss capacitors. The reason is different dielectrics have different properties. Look at the graphs again, Polypropylene, Polystyrene and Teflon all will exhibit very low DF at all temperatures, it's almost ruler flat across a very wide range of temperatures. The Mylar and all Paper capacitors have very large changes in DF with temperature, and in general at average temps higher than the other mentioned. As frequency increases to the point where impedance of the cap is very low the ESR from the higher DF will come into play much more with a paper/mylar type than with the others mentioned. The differences in dielectric and construction properties is what will yield different results and not so much manufacturer. Two manufacturers making similar construction caps from the same dielectric will show very similar properties that won't be audible. As an engineer brands are in the back of our minds. We choose a capacitor by the dielectric for a particular application. Once we know that we are using say a polystyrene cap for it's properties in an application then we may choose a reliable manufacturer for good measure. First and foremost it's always dielectric properties that dictate what cap to use in a particular application. That's why you see all different types of caps in devices, they all have their little niches and tradeoffs.

Of course one can install random capacitors into the filter networks and measure the output until you find the desired transfer function. A capacitor's real world characteristics are due to the dielectric material used and construction. It makes sense to either simply stick with the same dielectric material and construction method.for similar results. Or ask yourself what properties of any capacitors will effect the transfer function? Obviously the capacitance determines impedance and that's the largest factor but ESR also plays a role. I'm simply pointing out ESR matters and DF is a ratio between ESR and Xc so simply find any capacitor with similar DF characteristics and it should sound close.

You can see in the graphs above that Polyester/Mylar has similar DF vs Temperature characteristics as Paper in oil types. Look how Polypropylene, Polystyrene, and Teflon have extremely low DF at all temperatures. It should be clear to keep the same sound, when replacing a Polyester/Mylar capacitor use the same type or Paper will give similar characteristics.

If you want to keep the original sound you need to choose a slightly "imperfect" capacitor. I.e. it should have a low quality factor or conversely a high dissipation factor. Since dissipation factor is a ratio between ESR and Xc Xc = capacitive reactance ESR = Equivalent Series Resistance DF = ESR / Xc The reactance or impedance of the capacitor changes with frequency, as frequency increases Xc decreases as seen in the equation: 1 / 2*pi*f*c f = frequency c = capacitance in farads The ESR is in series with impedance of the capacitor - as the impedance of the capacitor decreases with increase in frequency there reaches a point where the ESR becomes a problem and attenuates the higher frequencies. Simply, the ESR slightly changes the transfer function of the filter network by reducing high frequencies. Say you have a capacitor with a DF=.1% and another with DF=.7% 2uF capacitor at 10kHz has an impedance of 7.95 ohms The ESR between the two caps is .001*7.95= .0079 ohms .007*7.95= .055 ohms Modern Polypropylene capacitors have a DF of .1% or lower, often lower, closer to .05% The original caps in Klipschorn were PIO but the vast majority have Polyester/Mylar film types like yours from 1969. Looking at a modern datasheet (linked below) for "Orange Drop" Polyester/foil type capacitor and it states maximum DF of .75 Also linked below will be the same "Orange Drop" capacitors but Polypropylene/foil type - scroll to page 8 for DF data and you'll see the maximum being .167 Paper is similar DF to Polyester and it's more linear. They sound very close, probably too close to even really say for certain but Paper caps might be slightly better sounding. https://www.cde.com/resources/catalogs/225p.pdf https://www.cde.com/resources/catalogs/716p.pdf

Looks great but I wouldn't trust a crimp connection on the capacitor leads.

Does the amp's cooling fan run when pushing the amp hard? Do you have plenty of ventilation around the vents of the amp? It sounds like the amp is going into protection from overheating and it could very well be a simple, inexpensive repair. Try removing the cover of the amplifier and use an external fan blowing at the internals while running the amp hard again. If it doesn't go into protection mode or if it holds up longer than it normally does than you know it's a temperature issue.

Plug two amplifiers into device; "Amp A" for one of your power amplifiers and "Amp B" to any other power amplifier. Hook one set of speakers to the "Speakers", the front switch's for each speaker both "L" and "R" have "Amp A" and "Amp B" selections separately so one could use Amp A for one "L" and Amp B for "R" or vice versa. Fun fact since these are just switches you could run it in reverse with one amplifier powering two sets of speakers. This time the speakers would be speaker "A" and speaker "B". Depends on your receiver. Some older receivers had RCA jumpers externally where the preamp and power amp sections split, no internal settings just run the preamp out to the tube amp. Most receivers have some sort of "preamp out" which should just be the front end section of the receiver. This is important because the power stage section is the one that will color the signal the most at low levels with higher harmonics. I'd probably still check the preamp out on an FFT analyzer to see how the output looks. As others have mentioned many have SET amplifiers that have no negative feedback and they like it that way for the extra low order harmonic distortion, mainly 2H. If the receiver's output contains higher harmonics at low levels then they are only going to be amplified by the power amp and mixed in with the original signal. It's not the distortion SET lovers want, it's a nasty irritating distortion that causes listening fatigue over time. Thankfully most reputable receivers "preamp out" will be fairly nice opamps that are so squeaky clean it won't impart nasty distortion like an output stage run at low powers. I've seen too many receivers running so cold that at low output power, like under 1 watt will have nasty harmonics from crossover distortion. These are the lower end receivers typically mass produced and run cold to get past warranty. If you know a good tech one can even have their "preamp out" section of the receiver modified to run in Class A mode which greatly improves the sound. With many opamps it's as simple as tying a resistor from the output to the rail. If the amp has a volume control than typically you set that to maximum volume and use the preamp section of your receiver for volume and tone controls. As a general rule of thumb it's good to be more safe than sorry but this is often greatly over exaggerated by far to many, especially if it's a low power SET amplifier. You can turn a tube amplifier "on" without it being hooked up to speakers as long as you don't run a signal through it. With no load on the power tubes there can be large voltage spikes that can break down the insulation of the output transformer. Of course if you have a 2 watt SET amp and the B+ is 250v and it's a modern hi-pot tested output transformer I doubt anything will be damaged even if you run a signal through it with no load. Most good amplifier designs will also have a loading network at the output to compensate for rising impedance with frequency on speaker loads, this filter should load the output enough to save the iron. Now if you have a vintage high powered tube amplifier with over 500v on the plates than running a signal through it with no load is asking for trouble. The higher B+ allows higher swings in the output transformer that may break down 60 year old winding insulation. Easy thing to remember, if you turn a tube amp on with no speakers don't play any music through it and no harm should come. I don't know why anyone would play music through an amp with no speakers hooked up but people do dumb stuff.

I started thinking about this more and your speakers really cannot handle more than 100 watts of power, and an honest 100 watt amplifier should make your ears bleed in a normal listening room. I actually more question the health of your current Pioneer. If someone wants me to look over their amplifier which is usually just some quick bench tests to see if the amplifier is meeting it's specifications. It takes longer to let the amp warm up, I usually let it sit for at least half an hour and then test power output vs distortion, check bandwidth at different power levels vs distortion and shoot some square waves through it for good measure. I charge $20 for this if I don't really know the person, for a friend or local person I know I usually just do it for free. Is there someone you can have check over the amplifier to make sure it's meeting is specifications? Even the protection circuits can be a source for malfunction, lots of old receivers that has DC protection usually has a sense pin that is AC bypassed with a large capacitor. These capacitors age and don't always shunt all the AC output signal and when pushing the amplifier hard will trigger the protection to kick in. There are lots of common problems, that's just an example. I just wanted to throw this out there in case it didn't cross your mind. 110 watts should be plenty of power and any more will actually damage your speakers.

You can probably get two of these for $500. He is selling them for $275 each. https://www.usaudiomart.com/details/649925159-outlaw-2200-monoblocks/

Bingo! Contemporary music I find is more geared toward choreographed dancing and less about artistic musical expression.

People ask me all the time what SET amps they should buy and I always push them towards the Elekit 300b amps. The circuit is very well designed and the performance and sound quality is far better than many 300b amps costing far more money. Mosfet B+ ripple filter DC filaments Switchable feedback from -8db to no feedback. I am very impressed with the Elekit 300b amp and that says a lot since I am extremely picky about designs.

Zeppelin was great at mixing time signatures. Black dog has 4/4, 3/4, and 5/4 The Ocean 4/4, 7/8 The Crunge 9/8 Yes!! Fell on Black days 6/4 Limo Wreck 15/8 My Wave 4/4, 5/4 The day I tried to live 4/4, 7/8 Spoonman 7/8

I have tons of records and enjoy them immensely, I'm not a perfectionist digital snob by any means. I read an article written by one of the big recording engineers, the name escapes me but he claims that some high frequency cross talk between channels improves the sound and is one of the reasons people love to listen to vinyl. So he actually mixes this high frequency cross talk into near perfect digital recordings to emulate vinyl on CD or streaming formats. I found that very interesting.

It's not irrelevant when you are listening to stereo recordings the other 50% of the time. Of course that is only if you have a source capable of excellent channel separation for stereo recording playback. Vinyl stereo playback systems have awful channel separation. Not really, no. If you are on the fence about whether to get mono amps or a stereo unit ask yourself what source do you use most? If you say vinyl then the cross-talk is horrendous with vinyl playback and mono amplifiers aren't going to matter since the pollution has already taken place at the source. If you listen to digital sources then mono amps will be technically beneficial the other 50% of the time when you listening to stereo recordings. Digital sources have excellent channel separation compared to vinyl playback. There are other benefits to running mono power amps other than channel separation. It's the lesser of two evils to have longer interconnects, especially balanced ones while keeping the mono amplifier directly next to the speaker with a very short speaker cable length.

If two separate channels process identical information then it stands to reason that cross talk through a shared power supply won't cause the same issues compared to two separate channels processing two different sets of information. The cross-talk pollutes one set of information from the other; each output no longer contains only the pure information that was at it's inputs. So if the two separate channels both contain identical information then cross talk won't matter and there is no benefit to two mono amps.

Here are some plots for different operating points. Readings taken at 10vrms output into 100k load. I have never seen a tube with no external feedback measure .0022% THD Although that's extremely low distortion there are some higher harmonics. It's not enough to sound horrible since 2H is still dominant but the second plot that's recommended Va=235 and Ia=28mA is still very low distortion at .028% THD but it's all second harmonic. Of course this is for line stage applications, the test is measured at 10vrms output, at 2vrms which most of the time is all that is needed to drive a power amp this tube is squeaky clean. If you want to try some I can send a couple your way as a Christmas gift. https://www.mvaudiolabs.com/tubes/tube-data-library/4p1l/

@henry4841 have you tried the 6AV5GA strapped as a triode yet? I know you like the 6Y6 a lot and it is a nice tube I found the 6AV5GA to sound better. Another tube that is better than the 6AV5GA and probably the best sounding tube I have ever heard in my life is the 4P1L. It's a Russian directly heated pentode but of course wire it as a triode. I thought something was wrong the first time I was taking distortion measurements it's that linear. It was a tough fight between the 45 and the 4P1L in my book for best no feedback sound and I have concluded the 4P1L is better sounding. I really think you would like both. I sent curiousgeorge some 4P1L's but not I don't think he has had the time to mess around with them yet. The 4P1L being directly heated filament is a little tougher to setup in that it works best with DC filaments like all directly heated triodes do. The 6AV5GA is much simpler to build with due to it being indirectly heated 6.3v heaters.

Don't believe everything you read on the internet. In what way is the connector limiting performance?

Pots don't always have to be noisy from something physically wrong like oxidation or contamination of the track. Since it's only one channel and it's a sealed pot you could be experiencing some DC current leaking by from a faulty capacitor. DC current passing through a pot makes noise when turning just like it was dirty. Of course it could just be a dirty/oxidized pot even though it's sealed. Careful disassembly and cleaning of the pot can resolve the issue. Anything assembled can be disassembled, pots included.

Of course it's a fine little amplifier, I wouldn't be spending my time on it if I didn't like the design. It's got the hallmarks of things I'm into like the 6Y6 tube. That's not a tube you hear about all the time like the chocolate/vanilla EL34/KT88 amps that flood the market. Elekit makes a nice 300b amplifier that has a switch to add 8db of feedback or leave it open loop. I'm not saying this amp needs negative feedback, but it might be a nice option for the end user to be able to decide for any recording they listen to or any pair of speakers they might have. It's just a simple "mod" that gives the end user more options and versatility. I know it's not needed but options are fun I think.