I used irf530 and irf9530 for years in a car amplifier that sounded excellent. 33v rails into 4 ohms. The next generation Irf530d oscillated and died immediately in the same circuit.
Lower drive requirements enhances stability.
Lower drive requirements enhances stability.
Kids' play? What I always do is test the most abstruse ideas that I read somewhere or that come to mind. I don't want to play hide and seek - behind some other, supposedly great ones;-) Bernie obviously don't know.
I have also experienced this: different batches sound different, and they also have different power ratings and more that do not correspond to the specified line and numerical values.
Our luck: we don't want amplify and look lines and numbers, we want listen music;-)
Regarding those »bad sounding« Hitachi LatFET`s from the early 1980ies: Let's remember David Hafler's contemporary amplifiers. Do they really sound bad? Then, Bob Cordell (I think it was him, wasn't it?) designed new driver boards to be installed in DH amps, keeping the original power devices and the PSU. Do you really think BC made this effort if the Hitachi's were that bad?
Unfortunately, 'till today I never had the chance to listen and judge an original DH amp, nor BC's upgrade. But I built the ELEKTOR Crescendo as a stereo power amp about 40 years ago. And this one doesn't sound bad at all, 'though the MOSFET's are voltage driven by a symmetric pair of cascodes (BC550/560 and BF871/872). I'm sure there once were application notes by Hitachi to the SJ50/SK135 family. What, which drive, did the original manufacturer suggest?
Best regards!
Unfortunately, 'till today I never had the chance to listen and judge an original DH amp, nor BC's upgrade. But I built the ELEKTOR Crescendo as a stereo power amp about 40 years ago. And this one doesn't sound bad at all, 'though the MOSFET's are voltage driven by a symmetric pair of cascodes (BC550/560 and BF871/872). I'm sure there once were application notes by Hitachi to the SJ50/SK135 family. What, which drive, did the original manufacturer suggest?
Best regards!
+12
A deceased friend devoted 15 years of his life to this amp and created different iterations of it until he assembled things that could only be lifted by two people.
A little before his death he literally exiled himself in the mountains in the middle of nowhere and from what I know, all his production (amps, speakers, turntables) (literally a shed) went to charity, since then I have been tracking down his creations on the second-hand market, but I only came across a pair of cables that a professional customer had bought from him and gave it to me.
I have always liked the crescendo even if it was "dethroned" later by the "Grand Mos".
For the above line of "Quasi" amps, there is an exhaustive thread in this site: https://www.diyaudio.com/community/threads/power-amp-under-development.43331. The thread was started by the developer. Not sure what the above blogspot site is.
The amp has been successfully built by lots of DIY starters.
Something like 3-4mW driver capability for a single pair at 100kHz and 50V pk output level.
That's what I'm saying, you should talk to him!
Seriously guys, the sort of care that mastering guys like him have with the music is mindboggling. These guys care about their entire audio chain up to the cutting lathe as if lives depended upon it. I watched quite a few interviews with Bernie Grundman on youtube and they're great, highly recommended!
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Common power supply between what you mean?
Also, you made me curious what could sound like 15K DAC for 200 Euros. Any recommendations or perhaps an explanation how that is achievable?
BTW I'm looking to buy the PA 940 that you recommended, just the owner is currently on holiday, so I don't know if I won't change my mind until he returns. Because I also know that nothing will play the bass like NC400 so if I'm thinking of active crossovers this amp would be for sure something that I will want. Or something similar class D, but I'm not aware of more options at the moment. So I might just decide to buy that and then with no rush at all look for something that I can use for upper mids and highs, probably modulus 86 or something better. Perhaps something not PP as per your line of reasoning. There's just huge gains to be had in forgoing passive crossovers and having good cables straight from the amp to the speaker (sorry can't follow the reasoning in simple hardware store monocore copper cable - there's just too much to loose). Also savings on passive crossover components. And a lot less complexity, but much more malleability in the system. I know there's massive gains in potential better DACs too but I think that's a little bit cost prohibitive, since a multi-channel DAC like Topping DM7 costs as low as 300-350 used (while good 2 channel DACs go into 1k territory until you get into real gains vs some cheap but good Topping or SMSL from 2020s) and I know how it plays and it's definitely enough to push through some magic into the speaker even if it's definitely not world class. It's pretty good still. Plus I think I just want to play more in the digital domain exploring the various crossover points and so on rather than the relatively slow and expensive way of building passive crossovers. And it's so much easier to adjust the phase!!! I hope you guys don't hate on active crossovers. If nothing else, it's a great learning tool. I think a tweeter connected straight to amp with a good silver cable is damn near unbeatable in how lively and not veiled it can sound. No matter the DAC or the quality/price of the passive crossover, it'd still be hard to beat. Well ok, there are much better DACs than DM7 but that thing is cheap and full of possible uses. And not necessarily a slouch itself either. It's a decent DAC.
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I would even recommend against the analog route, which is not available to you right now. I would recommend you to take the digital route;-)
Why would you waste your money on some cheap second hand PA Amplifier.
Because a member with seemingly much more experience than me is saying that there's something to it that's worth my time at least when modified... Honestly, maybe I should go to something with higher ceiling right off the bat but that's not a huge expense and could actually be something special if cumbb is telling at least some truth in his descriptions.
I know what the mainstream here would recommend to me and it would most likely be modulus 86 given my needs and desires and also the fact that I'll most likely be playing 1500Hz and up with it (although might play full range at first). But I could buy or build both (modulus and NC400), see what I like and sell one if needed. This wouldn't necessarily teach me much, but would play very well. There are a few options for me...
I absolutely adore NC400 for the bass, so if I acquire it, it will probably not leave my house, my problem with it is lack of rawness and emotion especially in vocals. So I'm looking for something A or AB. Low powered probably. Something equally detailed, energetic, incisive, but also much more lush, rich, emotional than Class D.
@cumbb what would you recommend if I was willing to experiment and build something, but perhaps a step above the PA 940? You have unique opinions man, I want to learn where your perspective is coming from. What if I wanted it just for highs and midrange? And if you care, my questions about DACs - I'm still very curious about. 🙂
If we were talking about low power Class A, what would be your top picks? I reckon you hold Aleph J to higher esteem than F5 Turbo? I love the recommendation to build it without the board. What else? What should I be looking for?
I have also just got the Hiraga Le Monstre up and running again and rebuilt it with my current knowledge. It sounds worlds better than an original or the usual replicas. It sounds great: concentrated, focused, the essentials put together. Tempo, contour, color, clarity... Party;-) But when I plug in one/my SE, the Hiraga only sounds like the solar system compared to the Galaxie: just the essentials. More like a model or symbolic representation of what is. You can hear what it's about, but so much is left out and not shown. And it is also "discolored" in comparison. A "linear frequency response", for example, is not a statement regarding color fidelity or tonal fidelity.
And yet I would recommend this Hiraga, for example, and not a small SE, because these SE stories also need a lot of experience in speakers, sources and everything else. In order for the sun to rise here, whose much higher potential is shown, a lot has to be taken into account.
The Aleph J will undoubtedly have a higher sound potential than the F5, but it would be a little too complex for me, and maybe for you too;-)
I would perhaps use two NX400s or two Modulus 86s. I would stick with identical amplifiers to keep the homogeneity. And would use one psu for all;-) It may well be that these sound better with a split of the work. It may be well also that they don't sound good in all respects because of some parts. But I'd have to have them in my hands and look and try a few things to prove it;-)
The PA-940 is a great thing, also in terms of sound. And exploring its sonic potential is another story. To call this "waste money in cheap" is nonsens because this cheap does not concern the potential in sound and experience;-)
And yet I would recommend this Hiraga, for example, and not a small SE, because these SE stories also need a lot of experience in speakers, sources and everything else. In order for the sun to rise here, whose much higher potential is shown, a lot has to be taken into account.
The Aleph J will undoubtedly have a higher sound potential than the F5, but it would be a little too complex for me, and maybe for you too;-)
I would perhaps use two NX400s or two Modulus 86s. I would stick with identical amplifiers to keep the homogeneity. And would use one psu for all;-) It may well be that these sound better with a split of the work. It may be well also that they don't sound good in all respects because of some parts. But I'd have to have them in my hands and look and try a few things to prove it;-)
The PA-940 is a great thing, also in terms of sound. And exploring its sonic potential is another story. To call this "waste money in cheap" is nonsens because this cheap does not concern the potential in sound and experience;-)
There was a table of Nelson Pass' amplifiers somewhere, listing their various characteristics, and the F1 and F2 stood out for me for having the highest output impedance. Some of the more esoteric drivers like ribbons might not benefit much (or at all), but regular cones and domes will probably thank you for it.