So you are good with the Alpha amplifier’s performance as a test? Will see what I can do as the problem is my amps are often temporary (many in “reserves” mode) as I move from one project to the next and some work is involved in moving an amp back to “active” duty.
A good motivator for me is to finish my ABBB amp build and test it as it has basically the same protection circuit built in. Also can test with the present compact SSR DC protection module.
A good motivator for me is to finish my ABBB amp build and test it as it has basically the same protection circuit built in. Also can test with the present compact SSR DC protection module.
Hi X,
Since I’ve been playing with the ABBB that has this SSR DC protection/delay circuit built in and see how well the delay works at eliminating turn on thumps/cone movement and the added “insurance” that my speakers are protected, I pulled the trigger and purchased a pair of these RTR stand alone boards.
I use a PeeCeeBee V4H amplifier that I wanted to add a speaker protection circuit to but, I didn’t want to use a relay based circuit. This SSR should be a great solution!
Do you have an approximate timeframe of when you’ll get these shipped out?
Cheers,
Vunce
Since I’ve been playing with the ABBB that has this SSR DC protection/delay circuit built in and see how well the delay works at eliminating turn on thumps/cone movement and the added “insurance” that my speakers are protected, I pulled the trigger and purchased a pair of these RTR stand alone boards.
I use a PeeCeeBee V4H amplifier that I wanted to add a speaker protection circuit to but, I didn’t want to use a relay based circuit. This SSR should be a great solution!
Do you have an approximate timeframe of when you’ll get these shipped out?
Cheers,
Vunce
Sigh. No. You've shown those test results earlier in the thread. That's what prompted me to write in the first place.
Your claim is that your speaker protection circuit is not causing any degradation of the signal because it doesn't degrade the THD of an amp with high distortion. That's equivalent of saying, "I can't hear you whisper while I'm at this rock concert, therefore, you can't be whispering anything important".
Tom
Tom,
If you had paid attention to what I was posted you would have noticed that the first measurement was the Deltic Class AB. This did not satisfy you. I did not have another speaker amp handy. So I made a measurement with a headphone amp because you were in want of a low distortion amp. That did not make you happy. So I showed you the Alpha Class A amp with 10x less THD than the Deltic Class AB. You then assumed this was the same amp as the Deltic without checking the facts. Have you heard of the “Bring me a rock” story? Let’s not do that. We will provide measurements when we are ready. In the meantime, you need to tone it down a notch. We can do without the sighs. Not everyone has or needs an amp with 0.000025% THD - it’s not the amount but the profile. And I have shown that it doesn’t alter the profile nor the THD at the typical levels of distortion we see in many amps in this forum where 0.05% and 0.005% are typical.
I did not say “that it does not cause any degradation in the signal”. Here is what I said from post 1:
All true: no noticeable artifacts in the time domain based on the O-scope traces, and no effect on the harmonic distortion profile (Deltic Class AB).
If you had paid attention to what I was posted you would have noticed that the first measurement was the Deltic Class AB. This did not satisfy you. I did not have another speaker amp handy. So I made a measurement with a headphone amp because you were in want of a low distortion amp. That did not make you happy. So I showed you the Alpha Class A amp with 10x less THD than the Deltic Class AB. You then assumed this was the same amp as the Deltic without checking the facts. Have you heard of the “Bring me a rock” story? Let’s not do that. We will provide measurements when we are ready. In the meantime, you need to tone it down a notch. We can do without the sighs. Not everyone has or needs an amp with 0.000025% THD - it’s not the amount but the profile. And I have shown that it doesn’t alter the profile nor the THD at the typical levels of distortion we see in many amps in this forum where 0.05% and 0.005% are typical.
I did not say “that it does not cause any degradation in the signal”. Here is what I said from post 1:
All true: no noticeable artifacts in the time domain based on the O-scope traces, and no effect on the harmonic distortion profile (Deltic Class AB).
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All I am asking you to to show the performance of your circuit when used in its intended application such that consumers can make an informed choice. Is that really so unreasonable?
Both amps would obscure the THD of your circuit (assuming your circuit works well).
You make available a circuit that is intended for use in a power amp. You show a measurement that contains so much distortion that it obscures the distortion of your circuit and claim that your circuit isn't adding any distortion. I pointed out that your measurement didn't reveal anything about the performance of your circuit and that you would need a low distortion amp to test it. You took this to mean that any low distortion amp, including a headphone amp with light load (3 kΩ), would work for this. That indicates to me that you either don't understand the distortion mechanisms in your circuit and how they depend on device current; or that you're just blowing smoke to make me go away.
All I'm asking is that you provide a scientifically sound measurement. I.e. one that has high internal validity and high external validity. This is not an unreasonable ask.
What I would like to see is a measurement of the THD+N vs output power and THD+N vs frequency for your circuit when used in its intended application. If the intended application is a speaker amp, I would like to see the measurements performed with a POWER amp and a SPEAKER load (4 Ω and 8 Ω). Ideally, your measurement would include data points at the maximum power or voltage your circuit is designed for. If you would like to include FFTs so you can see how the spectral composition changes (or doesn't change), that's great. Have at it.
To perform this measurement you will need a power amp that distorts less than your SSR, otherwise the power amp's THD will just obscure the THD of the SSR. You can build progressively better amps if you desire, but the easier way would be to just buy a Benchmark ABH-2 as that's one of the lowest distortion power amps on the market. Should you not have the budget for a $3k amp, you can build a single channel of my Modulus-86 for $120 and be done. The Modulus-86 provides about the same performance as the ABH-2 within its power envelope. Alternatively, you can design your own. It's DIY after all...
Does that make sense?
That's funny, because above the second FFT plot in Post #1, you wrote:
How should I interpret this if not as "the SSR does not add any THD that I can measure".
BTW: "I don't know" or "I don't have those data available" are perfectly reasonable answers.
Tom
Both amps would obscure the THD of your circuit (assuming your circuit works well).
You make available a circuit that is intended for use in a power amp. You show a measurement that contains so much distortion that it obscures the distortion of your circuit and claim that your circuit isn't adding any distortion. I pointed out that your measurement didn't reveal anything about the performance of your circuit and that you would need a low distortion amp to test it. You took this to mean that any low distortion amp, including a headphone amp with light load (3 kΩ), would work for this. That indicates to me that you either don't understand the distortion mechanisms in your circuit and how they depend on device current; or that you're just blowing smoke to make me go away.
All I'm asking is that you provide a scientifically sound measurement. I.e. one that has high internal validity and high external validity. This is not an unreasonable ask.
What I would like to see is a measurement of the THD+N vs output power and THD+N vs frequency for your circuit when used in its intended application. If the intended application is a speaker amp, I would like to see the measurements performed with a POWER amp and a SPEAKER load (4 Ω and 8 Ω). Ideally, your measurement would include data points at the maximum power or voltage your circuit is designed for. If you would like to include FFTs so you can see how the spectral composition changes (or doesn't change), that's great. Have at it.
To perform this measurement you will need a power amp that distorts less than your SSR, otherwise the power amp's THD will just obscure the THD of the SSR. You can build progressively better amps if you desire, but the easier way would be to just buy a Benchmark ABH-2 as that's one of the lowest distortion power amps on the market. Should you not have the budget for a $3k amp, you can build a single channel of my Modulus-86 for $120 and be done. The Modulus-86 provides about the same performance as the ABH-2 within its power envelope. Alternatively, you can design your own. It's DIY after all...
Does that make sense?
That's funny, because above the second FFT plot in Post #1, you wrote:
How should I interpret this if not as "the SSR does not add any THD that I can measure".
BTW: "I don't know" or "I don't have those data available" are perfectly reasonable answers.
Tom
Tom,
As you have explained, you are a businessman, selling product in a competitive market for profit.
Behave like one. Keep your thoughts of others products and leave your own reputation clean, allowing the market to figure out if your price is worth your price vis a vis other products which you might regard as inferior. Any concept of your opinion is tainted with your obvious agenda; we would never offer negative comments of your products, we are all aware you do a good product and your attack of XRK's products (which are offered at bargain basements products, significantly) looks very partisan.
I do not see you attacking the obvious snake oils guys, it seems you are unconcerned with their egregious products........
This should be the end of it. I will not enter into any of your threads. Please desist.
Hugh Dean
As you have explained, you are a businessman, selling product in a competitive market for profit.
Behave like one. Keep your thoughts of others products and leave your own reputation clean, allowing the market to figure out if your price is worth your price vis a vis other products which you might regard as inferior. Any concept of your opinion is tainted with your obvious agenda; we would never offer negative comments of your products, we are all aware you do a good product and your attack of XRK's products (which are offered at bargain basements products, significantly) looks very partisan.
I do not see you attacking the obvious snake oils guys, it seems you are unconcerned with their egregious products........
This should be the end of it. I will not enter into any of your threads. Please desist.
Hugh Dean
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Dusting off my VHEX+ amp designed by Valery, I used it as perhaps one of my lowest distortion amp available to me at this time. The VHEX+ is powered by an Abletec +/-53v SMPS with a CRC filter for each channel. The VHEX+ is not considered an ultra-low distortion but I think quite representative of many amps in use by members in DIYA with specs here:
Here is a photo of the setup using a Focusrite 2i4 and a Fluke 101 for the Vrms measurement. The Focusrite is controlled by the REW software and provides the signal source as well to enable frequency sweeps.
The nominal condition for the test was 14.21Vrms (40.2Vpp) into 8ohms or 25w rms.
Here is the measured distortion components (H2, H3, H4, H5, THD) vs frequency for the case without the SSR Protection in place. These are 1M point data sets and an average of 8 sweeps was used:
Here is the measured distortion components vs frequency for the case WITH the SSR Protection in place, again 1M points and average of 8 sweeps:
Here is an overlay plot showing the THD of both cases:
Here is a representative FFT for 1kHz excitation at 21.21 Vrms (40.2Vpp) into 8ohms for the case without the SSR Protection in place. Settings were 32k points, Blackman-Harris 7 window, 0.88 exponential averaging:
Here is a representtive FFT for the same WITH the SSR Protection in place:
And finally, here is the THD vs the Power in watts delivered to an 8ohm dummy load over a range from 65mW to about 32w. The power was adjusted and I manually connected/disconnected the SRR Protection circuit and replaced connection with a double-ended male-male Faston spade connector. The power setting was untouched to ensure identical conditions:
At the highest power setting, the THD actually was a tad less with the SRR Protection in place. That is not a typo.
I won't add any editorial comments to the above data, and I feel they speak for themselves.
Here is a photo of the setup using a Focusrite 2i4 and a Fluke 101 for the Vrms measurement. The Focusrite is controlled by the REW software and provides the signal source as well to enable frequency sweeps.
The nominal condition for the test was 14.21Vrms (40.2Vpp) into 8ohms or 25w rms.
Here is the measured distortion components (H2, H3, H4, H5, THD) vs frequency for the case without the SSR Protection in place. These are 1M point data sets and an average of 8 sweeps was used:
Here is the measured distortion components vs frequency for the case WITH the SSR Protection in place, again 1M points and average of 8 sweeps:
Here is an overlay plot showing the THD of both cases:
Here is a representative FFT for 1kHz excitation at 21.21 Vrms (40.2Vpp) into 8ohms for the case without the SSR Protection in place. Settings were 32k points, Blackman-Harris 7 window, 0.88 exponential averaging:
Here is a representtive FFT for the same WITH the SSR Protection in place:
And finally, here is the THD vs the Power in watts delivered to an 8ohm dummy load over a range from 65mW to about 32w. The power was adjusted and I manually connected/disconnected the SRR Protection circuit and replaced connection with a double-ended male-male Faston spade connector. The power setting was untouched to ensure identical conditions:
At the highest power setting, the THD actually was a tad less with the SRR Protection in place. That is not a typo.
I won't add any editorial comments to the above data, and I feel they speak for themselves.
Attachments
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xrk971 - 4 units - USA
pinnocchio - 6 units - CAN
Vunce - 4 units - USA
Miggie78 - 2 units - FINLAND
Nautibuoy - 2 units (maybe 4, depending on price) - UK
gary s - 4 units - AUSTRALIA
WTL- 4 units - AUSTRALIA
ppap64 - 2 units - CANADA
drpro - 4 units - USA
Alarudin - 2 units - SINGAPORE
Ripcord - 2 units - USA
Myint67. - 4 units - Singapore (depends on price )
av-trouvaille - 2 units - NL
ravid - 2 units - India
darrr - 2 units - Poland ( depends on price )
Avtech23 - 2 (maybe 4) units - Australia
bkdog - 4 units - Australia
necplusultra - 2 units - Dominion of Canada
gannaji - 4 units - USA
Amplitude - 2 units - Denmark
esprit - 2 units - UK
hirscwi - 4 units - USA
yoaudio - 4 units - USA
kamco - 6 units - USA
Baobei - 2 units - UK (depends on price)
Kokanee - 4 units - Canada
Abanico - 2 units - Spain
vasilis - 4 units - Greece
astromo - 6 units - Australia
mlloyd1 - 2 units - USA
markus22ch - 6 units - Switzerland
redjr - 2 units - USA
gtose - 2 units - USA
jwjarch - 4 units - USA
gktaudio - 6 units - USA
quadtech - 2 units - USA
livingstone - 4 units - RUS (depends on a price)
Bare - 2 units - Can
Quan - 4 units - Aus
MD_Stryker - 2 units - USA
tuyen - 2 units (maybe 4) - Australia
pinnocchio - 6 units - CAN
Vunce - 4 units - USA
Miggie78 - 2 units - FINLAND
Nautibuoy - 2 units (maybe 4, depending on price) - UK
gary s - 4 units - AUSTRALIA
WTL- 4 units - AUSTRALIA
ppap64 - 2 units - CANADA
drpro - 4 units - USA
Alarudin - 2 units - SINGAPORE
Ripcord - 2 units - USA
Myint67. - 4 units - Singapore (depends on price )
av-trouvaille - 2 units - NL
ravid - 2 units - India
darrr - 2 units - Poland ( depends on price )
Avtech23 - 2 (maybe 4) units - Australia
bkdog - 4 units - Australia
necplusultra - 2 units - Dominion of Canada
gannaji - 4 units - USA
Amplitude - 2 units - Denmark
esprit - 2 units - UK
hirscwi - 4 units - USA
yoaudio - 4 units - USA
kamco - 6 units - USA
Baobei - 2 units - UK (depends on price)
Kokanee - 4 units - Canada
Abanico - 2 units - Spain
vasilis - 4 units - Greece
astromo - 6 units - Australia
mlloyd1 - 2 units - USA
markus22ch - 6 units - Switzerland
redjr - 2 units - USA
gtose - 2 units - USA
jwjarch - 4 units - USA
gktaudio - 6 units - USA
quadtech - 2 units - USA
livingstone - 4 units - RUS (depends on a price)
Bare - 2 units - Can
Quan - 4 units - Aus
MD_Stryker - 2 units - USA
tuyen - 2 units (maybe 4) - Australia
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I agree that this is a representative sample of a low distortion (but not ultra-low distortion) amp similar to what many DIY Audio folks would have. Excellent!
I've seen that as well in some of my measurements. I suspect the MOSFET switches add a little extra capacitance, which shaves off a pico-bell of bandwidth, which lowers the harmonics. I have no hard science to back up this claim. It's just my handwaving explanation for why that might be.
I feel they speak for themselves too. Now we know that the SSR distorts less than what a representative power amp does, thus, that it will likely be sonically transparent with those amps.
Thank you for following up. I'm sorry I ticked you off earlier. I should have been more specific in my original request.
I'm sorry to see that people are dropping off due to import fees. Really?? C'mon... I'm actually impressed that you're able to get this circuit manufactured and assembled for $40 - and hopefully still have enough left over for a cup of coffee for your trouble. Good for you.
Tom
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Thank you Tom, very gracious post.
XRK and I are very interested in THD, but like to go further and measure and analyse the first six or seven harmonics. THD alone is not fully describing what is happening; a thorough monotonic decrease we have found gives very good sound.
I realise this is not conventional and might be dismissed as incorrect; that's fine, not everyone thinks the same way. Our work is revealing some interesting psychoacoustic issues which are more important to human hearing than the engineering issues which have dominated for sixty years.
Aspen has been using SS relays for four years now and they really are transparent, and superior protection for expensive speakers.
Hugh
XRK and I are very interested in THD, but like to go further and measure and analyse the first six or seven harmonics. THD alone is not fully describing what is happening; a thorough monotonic decrease we have found gives very good sound.
I realise this is not conventional and might be dismissed as incorrect; that's fine, not everyone thinks the same way. Our work is revealing some interesting psychoacoustic issues which are more important to human hearing than the engineering issues which have dominated for sixty years.
Aspen has been using SS relays for four years now and they really are transparent, and superior protection for expensive speakers.
Hugh
Hi Tom,
Apology accepted. Thanks for clarifying what you were looking for and I am glad that the data that I provided gives you the info you need to say that this circuit will do what it was designed for.
I am not sure what the reason is for apparent sticker shock people are getting. The cost of this is no more than cost of typical amplifier PCB’s folks happily signed up for in the past, tariffs/duties/taxes and all. As you know very well, $40 is not a lot to ask for a RTR state of the art all SMT design by two members with a combined 60yrs of electronics design experience, professionally assembled by a manufacturing board house, and individually verified and tested by myself. Yes, “coffee money” as we say. Although I do like espresso - perhaps payment can be made in sleeves of Arpeggio Nespresso capsules?
Apology accepted. Thanks for clarifying what you were looking for and I am glad that the data that I provided gives you the info you need to say that this circuit will do what it was designed for.
I am not sure what the reason is for apparent sticker shock people are getting. The cost of this is no more than cost of typical amplifier PCB’s folks happily signed up for in the past, tariffs/duties/taxes and all. As you know very well, $40 is not a lot to ask for a RTR state of the art all SMT design by two members with a combined 60yrs of electronics design experience, professionally assembled by a manufacturing board house, and individually verified and tested by myself. Yes, “coffee money” as we say. Although I do like espresso - perhaps payment can be made in sleeves of Arpeggio Nespresso capsules?
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GB Status Update...
We are a go with this project, please place your pre-orders and update the list as we go. I will remove the two members who are having heartburn with duties for products into the EU.
Again, price is $40ea and shipping is FREE in the US, $10 in CAN, and $15 everywhere else.
Actually don’t see Tony.Garner’s name on the original list?
We are a go with this project, please place your pre-orders and update the list as we go. I will remove the two members who are having heartburn with duties for products into the EU.
Again, price is $40ea and shipping is FREE in the US, $10 in CAN, and $15 everywhere else.
Actually don’t see Tony.Garner’s name on the original list?
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I can only guess, but it seems many expect you to deliver top notch quality at eBay prices. Never mind that you can't buy the components at QTY=1000 for what the eBay vendors are selling theirs for ... including shipping! Heck, I can't even ship such a board like that across town for what the eBay vendors charge for a fully assembled module, including shipping. Oh, well. As Hugh said earlier: It's a competitive market.
Tom