Have you thought about doing a DIY project for a hybrid amplifier with Sparkos & tubes to get that tube quality with opamps? I know you have a ton of things planned but, I know I would be interested & think others would as well. Looking forward to your interview with the Sparkos guy!

This video is a great way to be shown how to install . You are the best !!!

Thanks for the great review! I added the Sparkos opamps to my pair of Fosi ZA3's running as stereo monoblocks. I was skeptical when I bought the Sparkos but they ended up improving the sound exactly as you described for the amplifier that you tested.

Spot on with the high pass filter. That makes absolute sense.

I think if you remove the knob and nut for the volume control, the amp will slide out, without de-soldering the speaker leads.

Looking forward to your Sparkos interview. 💜 This will be a unique, fresh conversation compared with the plethora of “me too” content churning out there. My guess is the op amps in this application generally serve in the role of voltage gain stage and input impedance matching. These little Class D amps have their place, but I am still living in the old days of hot running inefficient Class A biased amps for their sonic characteristics, especially in the midrange.

Great review! I am impressed at the construction of that little amp for the price. I definitely don't need any more amps now, but will keep this and the op amps in mind if I need a secondary system. Thanks for your review!

I have fallen in love with this A70, in the vocal performance is really impeccable, when I play my symphony the moment, has been conquered by him

Hi Stephe! It is amazing you decided to explore this opamp niche. I strongly recommend trying also Staccatto discrette opamps from Poland. For some reviewers, even better than Sparkos. I can arrange for your review a pair. I am in contact with Jacob, Staccatto company owner…

Enjoyed this. Good to see you stepping outside of the valve zone. I think people like me who love valves and solid state both welcome your very grounded views without being afflicted by the hype virus. These little chip amps and budget Dacs are democratising hifi and removing the financial barriers to entering the hobby. I'm lucky enough, and old enough to buy moderately expensive gear, but still like to play with the budget stuff.

The dragonfly red I agree is an amazing little DAC- highly musical !

Wow, just watched your last video about opamps, thanks for doing this so quickly, heard alot of good things about Sparkos.

To remove the plate, all you had to do was remove the 4 screws on the edges of the back plate, the two screws below the passive radiator, and remove the volume button. The button, washer and nut. Once this was done, the entire plate would slide out along with the back cover.

Opamp rolling is great, it can be done in all of hifi eletronic. I have done it in my phono preamp. Very happy with results. Thak you for great videos. Cheers :)

Good point on the sub out adjustment. Would be great to see a high pass filter for internal amp, and high pass cutout. Great idea.

Wonder if it would be too much of a good thing by putting the color preamp in front of it. Great video!

that’s some crazy description of sound

i like where these chips amps are going, i am definitely going for something like this as my next desktop amp!

Interesting experiment Stephe. Thanks for showing us

I bought the RodRain DAC that uses 10 opams 4 double is all you need to replace. Went for the Akliam LC5 the sound is great. Price is no where close to a Sparkos or Burson but I think you couldn’t hear the difference.

I could be wrong, but if you take the nut off the volume pot - the boards could be slid out the back? I fully agree with you on the Sparkos units - they make a *yuge* improvement. If you can fit them, (not in this amp), the SS2590 dual mono DIP8 adapter is even better than the SS3602.

Nice to see that the Sparkos op-amps gets the Skunkie seal of approval. I know Randy at Cheap Audio Man gives these a high rating as well, particularly for use in the Fios amps and the Geshelli DACs. Nice walkthrough as well. Despite knowing what to do already, I just found it entertaining to following along, as you describe things so well. As for the Dragon DAC, you might want to try the SMSL SU-1 DAC. That was another device highly touted by Randy. It is a very good entry level DAC at about $80. I had bought one and while it does make a noticeable improvement over my computer (USB) connection, I mainly bought it to get some magic out of an older commercial Pioneer DVD player that I use as a CD player. The funny thing is that the DVD player actually has a superior DAC built in when compared to the SU-1! I wasn't expecting that! So I have to go with something a bit more for that application, such as the Geshelli DACs

great video. i too have the sparkos but have hesitated to put them in my A07 Max until now (thanks Stephe) one thing i personally recommend. As i too was not impressed with class D on their own (mono blocked them as well)..Is to put a tube preamp before the A07. i have used cheap douk audio and the aiyima t2 or their latest T1 tube amps as pre amp. And it clearly improved the sound. rounded up the edges so to speak.

77 watts into 8 ohm and 118 into 4 ohm before clipping for the a70, pretty good! I have wanted to try those sparkos opamps - I have made an analogue equalizer design with an engineer where I can use them, but I haven’t got the money to build it yet. If you want to venture into trying to build it, I would be happy to share the build with you (schematics, bom etc.), left/right each with 12 channels. LC type. Each center frequency according to “C” at the standard 440hz tuning. • C0: 16.35 Hz • C1: 32.70 Hz • C2: 65.41 Hz • C3: 130.81 Hz • C4: 261.63 Hz • C5: 523.25 Hz • C6: 1046.50 Hz • C7: 2093.00 Hz • C8: 4186.01 Hz • C9: 8372.02 Hz • C10: 16744.04 Hz • C11: 33488.08 Hz

Very useful and inspiring !! Gotta try it!

Question? You can get an Emotiva Class A/B amp with 50 wpc into 8 ohms and 90 into 4 ohms with THD

7:46 I think using sockets for op-amps is a good thing. I don't know about the 3602, but in general, op-amps have a standard "pin out." There may be minor differences, like one may require an external compensation cap, while others don't, but accommodating that difference is easy. With the standardized connections, you can experiment with different amps, or replace and older one with an improved version. This is a common practice with older, cheap gear, that often employed 741 op-amps (0.7 V/uS !!!), that could be upgraded with high slew-rate op-amps.

I've had these sparkos running for 6 days now and they keep improving. Not sure how long the break in is on these but I've seen reviewers saying 200hrs. We'll see.

For some Dacs and few years old Rotel CDP’s, I might invest on Sparkos, but I’ll stick with the slightly more lowly Muses dual opamps - for now.. What I haven’t tried yet are parallel dual opamps..

Great review and insights as usual. Thank you! I got your comments about how these discreet Op-amps improved the sound. What measurable performance characteristics can attribute to the improvements that you heard? Better freq response? Better phase coherency? Lower distortion? Etc. Thanks, again.

I have sx52b in my ao7max, deeper soundstage, more separation.

I got a pair discrete opamps I got last year maybe I will now get around to installing them see what's up . Thanks!! I won a couple different smaller class d amps a year ago to. I just not done much with them yet

The discrete op-amplifier has a good sound

You should be able to disassemble *without* de-soldering. Instead of removing the rear panel, remove the volume knob and the pots retention nut, along with the machine screws from the rear panel, then slide out from the front, leaving the inputs/solders in place.

Discrete op amps like the SS3602, the even better SS2590, and Burson V7 series all run in class A operation with increased current capacity and can upgrade the sound of many audio component, particularly sensitive devices like DACs. Initially a doubter, I am definitely a believer having rolled all of these. As to which to consider for a particular device depends upon what one desires in system synergy, but the SS3602 is a good all-arounder in a compact package.

I'd appreciate your impressions of the more high-end class D amps versus comparably priced tube or even SS amps. It seems to me that class D has come a long way and has become a real contender for audiophiles. I own a Cambridge Audio EVO 150 and play it along side my Willsenton R8 (with Skunkie mods) and the EVO 150 sounds clean, articulate and "holographic". It's very enjoyable.

I'm a happy owner of their A08pro, diasppointed with their A07max which sound lifeless to me, but your video on this A70/Sparko opamp sparked my interest again on Ayima before I would venture into the more upscale Class D amps! Great post!

It is surprising, is that those op amps were the correct makeup for that unit.

It would be interesting to hear your findings when you compare a more pricier Class D to your tube amps.

Had the A07 and for a cheap amp blew me away. You have to run the right pre (preferably tube). Its not a $1000 amp killer. I would put it against my svs integrated though They have a full range aux out. They can be daisy chained.

Just what I need, thx🎉🎉🎉

You may want to start using a wrist strap and static free mat when working on any electronics with I/C's. Stepe, are the RCA inputs differential as well as the XLR (If so there are inner-connects that most don't know and that is Coax and twisted pair)!!! One must use the correct cable for compatibility. If your not sure there's a way to test with a Voltmeter, PM or call

I often saw car-amps & Class D amps quoting a wattage at 10% T.H.D. & many that give no distortion parameters whatsoever. I was very surprised how loud a proven 2, 5 & then 10 watts sounded via averagely efficient (89'db / 1'watt @ 1 metre) 8'Ohm speakers in a hi-fi shop's listening room once (with well damped walls & surfaces). In the mid 60's(?) to the 1980's, U.K. & imported amps kept to a German (I think?) "Specifications Code" folk called the "DIN 5000 spec's" where wattage was always given a 0.1% THD. Dont know if valve smps were spec'd at "DIN 5000 figures, but the 0.1% limit was often relaxed to 1% for valve amps under review in pre-net hi-fi mags. I cant imagine how 10% distortion in class D would compare to a valve amp's even-order of harmonic distortion, horrendous (verses a bit too grainey??) In those days, the influx of top-brand Japanese, U.K. & European solid state amps filled UK hi-fi mag's pages & It seemed like a "Specification War" where i recall my father & his friends agreeing, like many did "power amps make no difference to the sound if the specifications are the same" Wattage is still a missleading marketing tool, when 10% Total distortion is stated, as if it's fine

Nice video

Next opamp+tube hybrid amp 😉

I sense a turning point here.😮

I once put a BIOS chip in backwards. You guys can take "fry" quite literally.

Interesting results! I have a SMSL SA300 as my desktop amp and agree with your analysis af the sound quality of these class D miniamps (at least the ones I've heard so far). I have already added an external DAC which made e notable improvement but the sound still is only halfway decent. Now I wonder if adding Sparkos would benefit the SA300.

Good job with describing what you hear. Sparkos is $80 so $80x6=$480 which is way more than double what the Aiyima A70 costs though.

Hi! I really enjoyed your review of this unit. I’m curious about what 3.5 to RCA adapter you are using with the dragonfly? Thanks!

This would be around the price of a AXA35. Curious what would fit me better.

In my previous comment, I thought those "things" were sockets. Anyway, while the comment doesn't apply here, I'm leaving it, 'cause I think it's good advice, in general.

Put a carpet on the table to avoid scratches

I wonder if an electronic crossover might be an option for high-pass? Then the low-pass or even full-range output to the sub? Too expensive an option?

Prise off the front panel knob, remove the screws and front panel and then slide the whole assembly out backwards…?

I have a tube screamer type guitar pedal that you can change op amps to get a custom tone...I hever never seen this type of op amp with a board on top.. Do you think this could work ..It doesnt matter as long as it wont fry my pedal..I have tried a lot of them some sound great some not so great..JUst like trying things to get a cool unique guitar tone...

would it make sense to add these op amps if they're already upgraded on the DAC? Like if I was to pair a Geshelli J2 with this amp

Very good specs on these. Even better than LM833's! I was expecting you to say there was no change at all to the sound, so this is surprising. What were the numbers on the original opamp chips? TLO71? LF353? LM741? I'd be eally interested to know! Still, at $40 to $80 EACH, compared to $4 each for a pretty good LM833 chip. Plus there may not be room on your circuit board for these. I'd rather just get the parts & build them myself to try & save some cash. Good job though Mr. Sparko!

a question i have is if i swap op amps on a mono configuration like these ayimia 07. because im just using the left side . can i get away with just swapping one op amp and then leaving the right channel without an op amp?

why don;t they just have a B version with the op amp already installed

Would it be possible to remove the volume knob, and then remove the screws on the front, and have the whole assembly slide out the rear without having to unsolder anything?

I got on Apple Music to sample that Earl Klugh and I'm going to look for that album. But I was listening on my MacBook Air with AirPods and I wasn't getting that effect you hear, only left, right, center. I'll have to try streaming to my stereo to see if it makes a difference for me.

For some time I was also testing various little class D amps. They are OK for the kitchen or so but even for my desk I would not use them. You don’t have to have 5000$ speakers to hear that. Every half decent 20 year old class AB amp will sound better than these. And if you buy them used they are not even more expensive.

What is the power rating of the class D mini amp power bricks? A quick look at that spec will tell us the potential power output that may be possible....I see some of these kind of amps with tiny power jacks and small power bricks with claims of hundreds of watts....

Time to try this with a ...............color preamp........maybe it will , maybe it won't ..........

Dragon Fly Red's are good but an $80. SMSL SU 1 is superior in every way for a desktop or second system. It's not even close. The best bargain in Chi-Fi.

The A70 and the Sparkos will run you around 375 bucks with tax. So the question is where do you want to spend the money. Make that your price point and go on line and search for deals , open box and other sales. You might find an amp that fits your needs.

They're no better than IC op amps. Quite possibly worse. What were the original op amps?

High pass to bookshelf 🎉🎉🎉

Who says that Sparkos are an upgrade, implying that performance is improved by fitting them? There is no proof, but plenty of hype and anecdotal evidence.

Didnt like the sparkos, too bright for me.

To me putting this discrete opamps in is a bit of putting lipstick on a pig. Sorry to say. Class D will never surpass a good class A or even AB amp.

👍♥️🫂

cheapaudioman is very sad 😄