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So you are saying that all the hybrid amplifiers that exist on the market today, even those that are designed and built at the highest level by serious audio companies, are not good, inaccurate and do not give an audiophile sound? Listen, this is a serious statement

Any thoughts on experimenting with default negative gain and either a gain pot(as well as a volume)(lin or log...?) or a gain switch - say -3db and +6db. Might make an interesting and flexible unit. My partner likes music very low at times and I'm always scrabbling round the 7 o-clock position! N.B. Fback resistor say 1.5k - then parallel pot(wired as variable resistor) with a series resistor to set minimum resistance(and max gain)?

$500,000,000,000? - mmm, 'midfi'😄 Thanks for vid👍 - have picked up one of these really cheap for a play! I wonder if up-rating+grading the power caps/transformer will make an improvement.

So I'm back looking at your feedback resistor chart and thinking it would be nice to be able to adjust the gain in different applications. Why not use a double gang rotary switch with some daisy chained resistors to be able to adjust it. Start with your 100 ohm for the roughly 15 db gain and place a 56 ohm in series for the 12 db add another 100 ohm in series with that for a 9 db gain. Add a 220 ohm in series for the 6 db setting Next series an 820 ohm to give you around a 3 db gain setting. (Off the cuff estimates) As you switch to the next gain setting it just adds or subtracts from the total gain resistance. I would think if you used 1% tolerance resistors the gain of both channels should be very close I would also think you would need to use a switch that has make before break contacts or it might have issues if you switch ranges while it's operating. Just a thought, but someone might find it useful or worth experimenting.

There's nothing more a music producer likes than to be able to market the music as "remastered" as if there's an improvement on the result. This usually means digitizing the original analog recording and making them sound bright. Too bright in my opinion, to the point that they are unlistenable. One of the reasons why all original analog recordings cost so much. Even finding a mildly worn original analog release sounds way better than anything you can get today. And by the way, very few new vinyl recording are completely analog (designated by the AAA designation). What you are really getting is a CD on vinyl with all the limitations of vinyl.

With the cheap hybrid valve (pre) amps I wonder if the valve is even in the circuit. Might only have the heaters powered, eh? Interested to see @SkunkieDesignsElectronics review of some of those devices. I'm confident she'll look into the circuits and measure distortion levels.

Michael, you are so right about many of the issues you mentioned in this episode. I see products similar to what you described advertised on many websites. Valves or vacuum tubes seem to be added just as an advertising "gimmick". To critical listeners, much of what is broadcast on FM radio these days is to badly compressed and distorted that it is unlistenable. Only a few FM stations (in major cities typically) seem to provide a mostly low distortion signal if they broadcast classical music, jazz, big band music etc. Most of the rest is just garbage or rubbish. I personally have both solid state and vacuum tube audio equipment. With a well designed vacuum tube amplifier or a well designed solid state amplifier there is very little that can be discerned to be different between the two. Some early solid state amplifiers were not good to listen too for extended periods of time as they had their own distortion characteristics that exhibited higher odd order harmonics than was originally in the music to be reproduced. Much of the public today does not realize how distorted the audio is from today's sources. As you said, good audio amplifiers will allow the listener to hear the difference between a really excellently recorded music performance and one that is poorly recorded. Engineers test new equipment designs and the best strive for lowest total harmonic distortion and lowest intermodulation distortion. Keep up the good testing and reports! As always, you get what you pay for along with a good deal of education about the items desired.

Great test report, thanks ! Which is the C8 100pF capacitor you are suggesting should be adjusted down to 27pF ? Is it the one in parallel with the 47k input resistor or the one which is in parallel with the 1M resistor ?

I am so happy to see your return and you in good health. Thank you for your insightful videos always.

Valve preamps are probably just to achieve the magical valve sound. Accuracy was never the object.

Maybe I'll get one of those boxes, but I'll add a switch, labelled 'HiFi', & 'Distort', rather than the more normal labelling of 'bypass', & 'active' I don't have any valve design & building experience (other than melting a grid in a 6CM5), I obviously cannot do any worse than what's out there.

The best pre-amp is a passive pre-amp. no active components necessary. The only pre-amp you usually need is for a MM or MC cartridge and this amplifier cannot do either.

Impressive flat line there. Do you have its schematic, Or have you come across it in any platform? I'd really like to see.

Hello, I didn't understand the video because I don't know English. Why is there both an opamp and a transistor in this circuit? Aren't opamps a good preamplifier element on their own? For example, Muses02

Great great❤

Howdy, great video of the house build. The build looks a lot like the way we build up here in the cold arctic part of the world too, but i am sure you also had the same type of construction, back in the UK. Really interesting to look at all the options you have selected and how they have been implemented. Great video and a great house. I envy you a lot the climate you got down there, enjoy the warm weather and stay safe. Regards to you and your loved ones.

Great video. I plan to buy premade although I have the components in stock. The extra cost is nominal. RUclips suggested the video!

Very good video!

Thank you again for a great and educational video, i think i will have to build this PreAmp some time this coming winter. Will order it from ebay or AliExpress and see when i get around to solder it together and start using it. As always, great and really understandable content from you. Take care and stay safe. Best regards from Norway .

Hi friends, ... seems to be an interesting preamp-kit. really? to achieve a gain of a few dB I consider this circuit is absolute rubbish! adding a bunch of bipolar transistors after an audio-grade op-amp (NE5532 or LM4562) only for 300kHz bandwith is absolutely senseless an a waiste of components. high bandwith makes more RF-problems than giving a better sound quality. a bandwith of 50kHz (more than twice the bandwith of a cd-player) at very low !!! distortion can be easily achieved with a LM4562/LM49720 (ref. to datasheet) at an output impedance of around 1kOhm. if you really need lower output impedance add a buffer-stage after the IC and include it in the negative feedback path. this 'accuphase' circuit is nothing more than a component mass grave! the only sound determing components are the IC and C2 (100u) capacitors for dc-decoupling; NOT the two 100n capacitors in the DC-rails which are usually keramic caps.

What a terrible experience you have had there with multiple optometrists in your area. Really sad that those new "Optometrists Franshicse Stores" do often have way to much unqualified personell, or younger staff, that is not too interested in actually learning the trade of the business. Fitting different sized pads on is horrible service (sounds like the person doing that should probably invest in some new specs to be able to do their job properly...) Lenses refitted to old frames should always be cut and grinded to the correct fit for the frames, no need to use longer screws at all, if the job is done propely... My old frames have new lenses in and the whole thing took only 20-30 minutes at the shop, while i waited with a coffee... Costed way less than buying new frames when i needed new strength on my lenses. Well stay on track OM, and see you later, when you have some time and feel for posting new content. Just love your videos. Make sure to enjoy good quality time with your loved ones, and stay safe. Best regards

Really great to see you have a somewhat better health situation, and also spare energy to now make videos and post. Hopefully you also get to spend good quality time with your family. Todays "modern world" is sadly become way too much "use it and bin it" , so manufacturers do not want to build most things as quality products, but rather enjoy the gained revenue from us, have to purchase the items over and over again. But anyway, it is really nice to see you on your feet again, and your videos are really great. Take care, and stay safe, and enjoy the warm kiwi climate. Best regards from the cold areas of Norway :D

Blimey I've missed these videos. Thank you Michael.

I have bought several of these and the are kit, unassembled, and they go very well, and the price is ridiculous, I have tried changing operational and some change is noticeable, but it is almost better that brings (less distortion), although the sound in audio is something special, and not always sounds better which has better measures.🤗

I have one of the preamps you are talking about, and I understand everything you are saying. I have swapped out the valves for Mullards though, and the opamps for Muses 02. Howver, I'm sure all it is doing is adding distortion and colour, exactly as you say... Still, I am able to switch easily between the pure signal and the preamp signal to compare on the fly, and the preamp signal simply sounds richer and more pleasant to my ears. It adds what I can only describe as "sparkle" to the sound, a more 3D sound stage, which I really like.

If computer can do it sure audio system can be same

Hope they make next up 32 bits audio system up to 40 bits

Thank you very much. I am just your subscriber now from watching this video.

Different

I think the Fever 6J1 is the only cheap tube preamp that actually uses the tubes for amplification, without chip amps. There's a review on RUclips about it, and the review isn't too positive.

Makes perfect sense to me

This is one of the best amplifier channels on YT.

Good tubes with 2nd order even harmonics can add back the impression of an original recording, in my humble experienced opinion... For example, a Douk ST-01 Pro TUBE tip: If your amp came with Chinese 6k4 tubes (has a red star printed on the glass), mine caused distortion. I upgraded to much better sound for $17 with GE JAN 5654W matched pair tubes. 6k4 tubes can be replaced by 6J1, 6J2, 6J3, 6J4, 6J5, 6"1N, 64N, 65N, 5654/5654W, 5725, 6AK5, EF95, 6BA6, 403B, etc. Your tubes may be ok. Just an FYI free tip. Quality of each audio component matters. But money alone guarantees nothing. Good video.

You are correct Michael, tubes deform the waveform into an unnatural shape, producing a gently clipped sound that people like. But if you want accurate sound, a solid-state design is best.

I had a Vincent SV-226 integrated in my system for 5 years, and I thought it was quite nice. But I've used other hybrid integrateds, and they weren't anything special. But now I very much enjoy my tube preamp and Class AB mosfet power amp.

Um, thanks? I found out that the pre-amp I bought that proudly states that it uses an NE5532 has a counterfeit installed. Now my OCD won't let me leave it be (even though it sounds just fine). Parts and tools are now on order to replace it with a genuine device. Grrrrr...

There's this, using your favorite search engine: "Motherboard with integrated Vacuum Tube audio stage" That one didn't last long, and I doubt it sold many. I've never seen one in the flesh. One might ask why don't any of these USB audio interfaces have any tubes in them? For one thing they'd cost twice as much just for the extra circuitry to support and power the tube, but those interfaces only sell if they have REALLY GOOD SPECS and they won't if the signal is going through a tube/valve.

What's even worse than clipped? Bass drum cranked up 10dB above everything else through a compressor so it "ducks" everything at each kick. For some insane reason, younguns like it.

New Subscriber.

Thank you for Answering this Important Question. Low Voltage Valve Amplifiers are a complete Joke.

Some People confuse Detail with Edge/Surface Diffraction. So I Tame this apparent detectable Brightness. I attach an 8mm thick FELT RING around the Speakers Tweeter, so to help Attenuate HF Surface Diffraction. This can be a hidden Detail Killer or Color that makes some Speakers Tiring to listen to. Could you Please TEST this Idea so I know my Ear's are OK.

Actually, RUclips recommended me this video. Don't think that your videos are not recommended. Btw. I was looking to some preamps for phono.

Your videos very interesting! I am a valve fan because I like the soft clipping 2nd harmonic distortion ! I think it boosts the presence and makes the music sound almost live! I have also tried valves in the early stages feeding in solid stage F.E.T. Output and the results are very good! Matched pair Output valves like KT88, KT66 etc. As you rightly say are now very expensive (£ 130- 160 ) and I can’t afford to run them any more as I am now a pensonier! Some triode early pre amp valves are affordable but you have to watch Chinese cheapo types. If you buy through companies like Farnell you always get well made types that have been tested well! Companies like Farnell can’t afford to sell rubbish because it would damage their reputation! btw I have a question regarding valve equipment in general! Why can valve indirectly heated not use DC 6volt or 12 volt supply from a regulated linear smoothed psu to reduce hum? I know smpsu’s are noisy, unreliable, and no use for quality audio equipment! I have a GPO 48volt 10Amp DC linear Reg psu more than 50 years old and it still work’s perfectly today! What do you think? Fraser😊

I cant speak for mixing tubes w/Class D, my rig has a tube buffer on a Class AB amp and I prefer the sound with than without.

Great numbers on the bench. How does it perform at the output if the source has a small amount of DC-offset?

I'd switch the word "ever" for the word "yet".

Thank you for your lovely Channel Michael.

Well this is right at the heart of HiFi BS. Hifi isn't True Fidelity. It's about the consumerisation of audio. True Fidrlity Audio is about the asbscence of artefacts and so well designed components are not going to: Do this, And sound like this, And make your Pink Floyd sound different/better. HiFi can literally mean anything , anyone wants it to mean - it"s post-modern audio 😁. BUT the HiFi Rabbit Holes run very deep and wide and there are aways nerw ones being dug to catch the OCD types. Really well designed components simply don't have any sound at all - they are inaudible in the signal path. Find out what REAL unamplified music sounds like, no mics, amps , or spealers in the chain. It sounds very clear, clean and tonally accurate. It doesn't have depth, or layering or exagerated bass or anything similiar because it doesn't have the artefacts which produce these effects.

I've wrestled back and forth with this. It is accuracy vs what's sounds pleasing. Music is entertainment for most people, so I can understand wanting that harmonically pleasing distortion to make it more enjoyable. Assuming a digital source file is the same, and your amp stages (pre and power) are just passing on the truth, the two other major spots in the signal path where you will get differences would be the DAC and of course the speakers. Their deficiencies are sometimes fixed by the coloration amps may have.

You can have all the best fastest most accurate and expensive gear on the planet including the most expensive speaker system on the planet, your still listening to a turntable or tape deck or cd. Weakest links! Try and find anyghing good that isn't accoustic strings or wood wind! Iv'e heard somepretty amazing sounding tube amps. Aren't they still making those? Also want to add, i have a quad 44 pre amp and it sounds like a pile of crapp. Not sure what Quad was thinking there. Too bad they aren't still around to try and redeem themselves. Keep up the great work Mike, love your videos input and opinions😊