Apollon Audio Purifi Amp Popping issue

[foden2025]

Hi all,

A long time lurker here but didn't have an account before, my current issue is a very high popping sound I noticed on my new Apollon Audio Amplifier Purifi Eigentakt 1ET6525SA. The amp was giving me random popping sound for the first week I received it and all my mind was it's the SMSL DAC (Raw-MDA1) or Audirvana upsampling. But yesterday I went deep into troubleshooting DAC was off and no music and still there is a popping sound. I moved the left speaker cable to right and the popping moved. I removed the xlr and left only the amp and speakers on and this time even a higher popping sound like almost cracking the tweeter. I tried RCA instead of XLR and still a popping sound what I notice is it's getting worse than before it gets higher and more frequent. Installed my old Rotel Amp as before and for hours today no popping whatesover. I contacted Apollon already and waiting for response. But anyone have an idea what's the cause?

 

[Rit]

I hope you get this solved I have a similar amp from Buckeye, no issues.

 

[DVDdoug]

I don't know what's causing it, but of course a defect in a high-power amplifier could be dangerous to your speakers and there's no way to know if it will get worse.

 

[sushi_sensor]

I don't know if it's related, but my Blusound Power Node broke about 2 years after I started using it and wouldn't turn on. There was a popping noise right before it broke. I didn't ask for a repair, so I don't know what caused it. And I just ordered the same amplifier you got from Apollon audio as a replacement. It was a little late in delivery, and now this is even more depressing news. I sincerely hope that your problem is resolved.

 

[foden2025]

For diagnosis, Apollon advised me to switch the op amps to check if it stays on the left speaker or not. And it was still on the left speaker and it reached a level of very high popping noise that I had to run to turn off the amp. They identified the issue as a faulty Purifi module and are sending a replacement I'll keep the forum posted once it's resolved.

 

[Golfx]

For diagnosis, Apollon advised me to switch the op amps to check if it stays on the left speaker or not. And it was still on the left speaker and it reached a level of very high popping noise that I had to run to turn off the amp. They identified the issue as a faulty Purifi module and are sending a replacement I'll keep the forum posted once it's resolved.

Please do let us know. Thanks

 

[sushi_sensor]

It's a significant burden, and frankly, quite regrettable, when users of products from smaller manufacturers have to act as their own field engineers whenever issues arise.
There's always a risk of secondary damage when disconnecting or connecting circuit boards and connectors.

 

[Apollon Audio]

It's a significant burden, and frankly, quite regrettable, when users of products from smaller manufacturers have to act as their own field engineers whenever issues arise.
There's always a risk of secondary damage when disconnecting or connecting circuit boards and connectors.

With all due respect, we proposed a simple diagnostic step to the customer in order to expedite the resolution of the issue. One of the core design principles of our amplifiers is their modular architecture, which allows for straightforward diagnostics and component replacement, something rarely achievable with traditional, monolithic designs from larger manufacturers.

The customer was fully informed and willingly agreed to perform the basic test we suggested. As a result, we were able to accurately isolate the issue to a single module, which we are now replacing immediately. If the customer had preferred not to participate in troubleshooting, we would of course have arranged for a return shipment, but that route would have significantly delayed the resolution.

This modularity is not a burden, it’s a feature. It empowers the user with the option to resolve problems quickly, without the need to ship an entire unit across the continent and wait weeks for return logistics and bench time in a service center. In this case, the fix involves unscrewing four screws and sliding out a plug-in module, a task that requires no special tools, no technical background, and no risk of circuit-level damage.

We also provide live 24/7 support to guide users through such steps if needed.

It’s worth reflecting on whether forcing customers into long, opaque service chains—typical of many large manufacturers, is really the more user-friendly approach. We believe in transparency, speed, and flexibility. And in this case, our method allowed the customer to go from problem identification to solution in a fraction of the time it would typically take through conventional service models.

Respectfully, we view that as an advantage, not a drawback.

 

[IngMishael]

It's a significant burden, and frankly, quite regrettable, when users of products from smaller manufacturers have to act as their own field engineers whenever issues arise.
There's always a risk of secondary damage when disconnecting or connecting circuit boards and connectors.

Lol what?

 

[tmtomh]

With all due respect, we proposed a simple diagnostic step to the customer in order to expedite the resolution of the issue. One of the core design principles of our amplifiers is their modular architecture, which allows for straightforward diagnostics and component replacement, something rarely achievable with traditional, monolithic designs from larger manufacturers.

The customer was fully informed and willingly agreed to perform the basic test we suggested. As a result, we were able to accurately isolate the issue to a single module, which we are now replacing immediately. If the customer had preferred not to participate in troubleshooting, we would of course have arranged for a return shipment, but that route would have significantly delayed the resolution.

This modularity is not a burden, it’s a feature. It empowers the user with the option to resolve problems quickly, without the need to ship an entire unit across the continent and wait weeks for return logistics and bench time in a service center. In this case, the fix involves unscrewing four screws and sliding out a plug-in module, a task that requires no special tools, no technical background, and no risk of circuit-level damage.

We also provide live 24/7 support to guide users through such steps if needed.

It’s worth reflecting on whether forcing customers into long, opaque service chains—typical of many large manufacturers, is really the more user-friendly approach. We believe in transparency, speed, and flexibility. And in this case, our method allowed the customer to go from problem identification to solution in a fraction of the time it would typically take through conventional service models.

Respectfully, we view that as an advantage, not a drawback.

Indeed! A larger manufacturer would not engage in this kind of dialogue with the end user - they would say you have to send it in to them or their authorized repair center for diagnosis and repair, and the end user would be without it for a longer period of time, and would have to put the entire unit through two-way shipping abuse, and would have to depend on the judgment, skill, care, and thoroughness of whatever 3rd party repair center the manufacturer contracted with.

I would vastly prefer to be able to email directly with someone at the company, who is directly involved in the design and/or production of the gear, do my own troubleshooting, and hold on to my unit while the company sends me the relevant replacement component.

 

[foden2025]

I have to say I was relieved when Apollon offered they would send a replacement instead of me sending the item back and waiting for them to fix it. I received the module today and was able to install it only a stripped screw gave me a hard time but I like that the amp is user friendly. I don't get any pops as before but I will keep Apollon knows if any issues arises. No complaints so far for the service and item quality and I'll buy from them again in the future.

 

[muzak156]

Hi all,

A long time lurker here but didn't have an account before, my current issue is a very high popping sound I noticed on my new Apollon Audio Amplifier Purifi Eigentakt 1ET6525SA. The amp was giving me random popping sound for the first week I received it and all my mind was it's the SMSL DAC (Raw-MDA1) or Audirvana upsampling. But yesterday I went deep into troubleshooting DAC was off and no music and still there is a popping sound. I moved the left speaker cable to right and the popping moved. I removed the xlr and left only the amp and speakers on and this time even a higher popping sound like almost cracking the tweeter. I tried RCA instead of XLR and still a popping sound what I notice is it's getting worse than before it gets higher and more frequent. Installed my old Rotel Amp as before and for hours today no popping whatesover. I contacted Apollon already and waiting for response. But anyone have an idea what's the cause?

opamp ordered sonic imagery but was shipped with standard opamp 1652 - after a 60 day wait - highly disappointed so far may return the unit haven’t even taken out of box. waiting to hear what Tibor has to say before jump to any conclusions.I haven’t even plugged in yet awaiting a response but after 60days you’d think they’d get it right.

 

[JSmith]

opamp ordered sonic imagery but was shipped with standard opamp 1652 - after a 60 day wait - highly disappointed so far

Hello and welcome to ASR.

My suggestion is to get a refund on the extra you paid for the Sparkos as it's completely useless in comparison to the stock 1652.

'Sparkos SS3602 Opamp Rolling In Fosi P4'

Apr 3, 2025

This is a detailed measurements of effect of swapping the stock NE5532P op-amp in Fosi P4 preamplifier with Sparkos SS3602 "discrete" opamp. The SS3602 costs US $79.80 and the NE5532P, US $0.47.

Swapping opamps in P4 is more challenging due to back connectors/switches that need to be disconnected. I am not sure how successful I will be putting it back together as some of the tiny screws are almost stripped now. I looked and there was no obvious mention of swapping opamps in P4 from Fosi so I suggest not trying it regardless of what you are about to see.

So far, we have...

• amirm
• Replies: 347
• Forum: Stereo and Multichannel Amplifier Reviews

• 

'Op-amp Rolling Using Sparkos on Fosi V3 Mono'

Apr 2, 2025

This is a study of measured differences if one swaps up the TI NE5532p dual IC op-amp in a Fosi V3 Mono amplifier with a "discrete" opamp from Sparkos. It is a test requested in the youtube comments of my video test of the same using Douk A5 and Sonic Imagery op-amp. The Sparkos SS3602 retails for US $79.80 but I found a discount coupon that brought the cost down to $74.33 with shipping included.

Per Fosi documentation, there are three op-amps. The one at the bottom is only for unbalanced/balanced conversion. That leaves two op-amps to swap. Company says if you...

• amirm
• Replies: 348
• Forum: Stereo and Multichannel Amplifier Reviews

• 

'Discrete OpAmp Review: Sonic Imagery vs Sparkos'

Dec 11, 2019

Recently I reviewed the Nord Three SE 1ET400A Dual Mono Stereo Amplifier. That unit came with the Sonic Imagery's 990ENH discrete operational amplifier ("opamp") in the buffer stage (pre-amplifier). The owner then ordered a set of Sparkos Pro SS2590 discrete opamps. This gave me a chance to compare the two in the same platform.

Alas, this analysis while of some value, won't be conclusive as power amplifiers can have temperature and run to run variations. Still, the Purifi 1ET400A modules are very low distortion so the data is more likely to be valid than not.

The opamps are...

• amirm
• Replies: 147
• Forum: Stereo and Multichannel Amplifier Reviews

• 

There really isn't any reason then not to be using your new amp.


JSmith

 

[Apollon Audio]

opamp ordered sonic imagery but was shipped with standard opamp 1652 - after a 60 day wait - highly disappointed so far may return the unit haven’t even taken out of box. waiting to hear what Tibor has to say before jump to any conclusions.I haven’t even plugged in yet awaiting a response but after 60days you’d think they’d get it right.

I’d like to clarify the situation for the benefit of the forum readers:

Your amplifier was delivered after 1 month and 14 days from the date of order (shipping time and import/export customs included), not 60 days as stated. You ordered a Lux series amplifier, which has a published estimated lead time of 20 business days due to its custom build process.

Your initial order specified OPA1656 op-amps. The Sonic Imagery upgrade was purchased later. Unfortunately, due to an internal system glitch, the upgrade was not updated for our production team, and the build proceeded with the original OPA1656 op-amps.

As soon as the issue was identified, I offered to:
- Ship the Sonic Imagery op-amps to you immediately, free of charge.
- Refund the full upgrade payment you made for them as a goodwill gesture.

While I understand your frustration, it’s important that the facts are presented accurately. We take full responsibility for the mistake, have explained the cause, and have provided a fair resolution without requiring you to return the amplifier.

 

[JSmith]

OPA1656 op-amps

Just a friendly suggestion there Tibor, why not simply stop offering opamp "upgrades"? Then this won't ever be an issue again.


JSmith

 

[Apollon Audio]

Just a friendly suggestion there Tibor, why not simply stop offering opamp "upgrades"? Then this won't ever be an issue again.


JSmith

I understand the suggestion, but there’s no reason to stop offering op-amp upgrades. Many of our customers request them, and in certain input buffer designs, they do make measurable differences, something I’ve already demonstrated in previously published measurements here on the forum.

This particular case was not an issue with the op-amps themselves, but rather an internal system glitch that prevented an upgrade from being passed correctly to the production team. That’s now being addressed so it can’t happen again.

We remain committed to giving customers the configuration options they want while ensuring our internal processes handle them reliably.

 

[Golfx]

opamp ordered sonic imagery but was shipped with standard opamp 1652 - after a 60 day wait - highly disappointed so far may return the unit haven’t even taken out of box. waiting to hear what Tibor has to say before jump to any conclusions.I haven’t even plugged in yet awaiting a response but after 60days you’d think they’d get it right.

I believe you will find out that apollon does not allow returns for “custom built” amps.

 

[IngMishael]

I’d like to clarify the situation for the benefit of the forum readers:

Your amplifier was delivered after 1 month and 14 days from the date of order (shipping time and import/export customs included), not 60 days as stated. You ordered a Lux series amplifier, which has a published estimated lead time of 20 business days due to its custom build process.

Your initial order specified OPA1656 op-amps. The Sonic Imagery upgrade was purchased later. Unfortunately, due to an internal system glitch, the upgrade was not updated for our production team, and the build proceeded with the original OPA1656 op-amps.

As soon as the issue was identified, I offered to:
- Ship the Sonic Imagery op-amps to you immediately, free of charge.
- Refund the full upgrade payment you made for them as a goodwill gesture.

While I understand your frustration, it’s important that the facts are presented accurately. We take full responsibility for the mistake, have explained the cause, and have provided a fair resolution without requiring you to return the amplifier.

Glad to hear your side of this cos that didn't sound like Apollon at all

 

[muzak156]

Just a friendly suggestion there Tibor, why not simply stop offering opamp "upgrades"? Then this won't ever be an issue again.


JSmith

I believe Tibor is upset with my post, according to him it was a custom build which as he says takes 20 days. I finally plugged in the amp and am impressed with the build quality & sound, even with the default op1656 and he is willing to resolve the issue. The only reason I was disenchanted with my experience was because I stayed in communication via his online chat and via email reminding them to be sure to include the Sonic Imagery SI994, but I never rushed them. But based on other posts, someone in Apollon Audio chain is not processing orders correctly because shipping amps with custom paid request ie opamps seems to be common place. Otherwise in the 2days I’ve been testing it, it does exude quality. So aside from having to wait for my opamp (which they should dhl express to me, well see). I didn’t like was that a nearly 1800 amp doesn’t come with a power on button if you opt for the trigger, strange huh. Ty Tibor

 

[muzak156]

Just to be perfectly frank, Tibor is right he did offer to make the production error right, though still awaiting the SI994 and affirmation that he will be expressing over the missing part. As for the sound with included opamp 1658, not impressed, I know it improve when the new SI994 is added. I have not heard any popping, hum or crackling sound coming from the new amp and certainly hope I don’t!
And hes also right that the addition of the op amp was made a day after initial order. Other than that I still have faith in Apollon Audio and hope we can amicably resolve this issue. If I can make any recommendation to Tibor and his team, it would be that whoever is responsible for adding custom request to the production sheet be spoken to, as it apparently seems to be becoming somewhat of a trend despite their excellent build quality and resolution attempts. Also That perhaps add a line of code to their website that clearly states if you opt for a power on trigger, you will not get a power-on switch: that its one or the other. They don’t add a standard power on button with the trigger, however strange that may be. I erroneously thought all amps come with a power on button and if you opt for the trigger then you get one for the additional trigger costs, not that it excludes a power-on button, entirely. Other than that great build quality and in 48 hour trial so far no popping or crackling coming from this new amp. Great Job Apollon Audio.