Class A Amplifier – Hype or Reality?

If you want other available Class A amplifier options in India, at that price range you should definitely check out Sugden A21/A21SE, should be in stock with indian distributor. Sugden's are considered to be one of the best class A amps.

There was on A21SE for sale as well in classifieds
Thank you. We check around for a possible audition. It is listed on HFM for 3.96L
 
Last edited:
The newer amp camp amp with diy efforts
Unfortunately, I am miles away from any sort of DIY
Let me contact AP and see what options they have
As per the reply from Absolute Phase, they have 3 options:
-->
1) "We only have Pure Class A SS from Pass Labs upwards of 11 Lakhs"
2) "Invention Audio Pure Class A 20W power = Rs 4 lakhs"
3) "Invention Audio Pure Class A 10W power = Rs 2 lakhs"

Prices are inclusive of GST, Exclude freight cost at actuals.

Payment: 100% Advance

Delivery: 8-9 weeks after receiving PO & 100% Advance.
-->


For all of the above we need a Pre separately. I have asked for specs sheet of 2) and 3) since the website of Invention Audio does not have it. 1) is way beyond my reach. Will share the specs once I receive it
 
Unfortunately, I am miles away from any sort of DIY

As per the reply from Absolute Phase, they have 3 options:
-->
1) "We only have Pure Class A SS from Pass Labs upwards of 11 Lakhs"
2) "Invention Audio Pure Class A 20W power = Rs 4 lakhs"
3) "Invention Audio Pure Class A 10W power = Rs 2 lakhs"

Prices are inclusive of GST, Exclude freight cost at actuals.

Payment: 100% Advance

Delivery: 8-9 weeks after receiving PO & 100% Advance.
-->


For all of the above we need a Pre separately. I have asked for specs sheet of 2) and 3) since the website of Invention Audio does not have it. 1) is way beyond my reach. Will share the specs once I receive it
This is good information @Pratyush J … Pruthvi is a great guy from Absolute Phase.
Why not look at hand carrying the Firstwatt Amp if at all you happen to travel to the USA. You can directly reach out to Nelson Pass himself for any queries and he will give you any information you need.

If you are looking at an integrated Class A then you should consider this in case you can hand carry it.
While the new one retails for about 8K USD you may stumble upon a used one under 4.5 to 5K USD.
 
Just my 2 cents
We have some wonderfull diyers in this form who had helped a novice like me in diy with wonderful class A amps, got my amp camp amp, f5 turbo v2, jlh made by them and all three costed me one fifth the cost of the listed one
I appreciate your suggestion. I am aware that many talented guys build things for themselves and have read numerous threads about their creations. Unfortunately, a recurring theme among many of those threads was that the builds took a long time (sometimes years) to finish because the guys had their own priorities. I'm not sure how fervently they'll adopt builds for others. I would find it tough to follow up with them due to my busy schedule. My friend had to wait 8 months to receive his class AB amplifier. I'm not trying to generalize; I just want to spend what little free time I have listening to music. I would, however, be pleased to work with anyone (pls DM) who can build a Class A for me within a specific timeframe. Just an example, I have been planning to install a kill switch in my swift for last 6 months, not able to get time to finish 1 hour work inspite of having the entire kit with me.
 
Payment: 100% Advance

this is another pain area if i want to buy a kinki or denafrips dealers are asking 100% advance and 6 weeks waiting. For my pontus ii dac I paid 50% advance and rest on delivery max by y weeks. I received it in 8th week.

Are the dealers doing business with our money or is it the company policy??
 
Payment: 100% Advance

this is another pain area if i want to buy a kinki or denafrips dealers are asking 100% advance and 6 weeks waiting. For my pontus ii dac I paid 50% advance and rest on delivery max by y weeks. I received it in 8th week.

Are the dealers doing business with our money or is it the company policy??
A very valid point, but, I guess that's how things work in India especially in AV and Automobiles segments. We might be digressing from the original topic of the thread, so best would be to start a new thread for every one to chime in just like there is a thread "Don't buy anything in Audio without "Return" policy - Begin a movement in India" here
 
A very valid point, but, I guess that's how things work in India especially in AV and Automobiles segments. We might be digressing from the original topic of the thread, so best would be to start a new thread for every one to chime in just like there is a thread "Don't buy anything in Audio without "Return" policy - Begin a movement in India" here
Sorry for the OT, @Mod's please delete it
 
A very valid point, but, I guess that's how things work in India especially in AV and Automobiles segments. We might be digressing from the original topic of the thread, so best would be to start a new thread for every one to chime in just like there is a thread

"Don't buy anything in Audio without "Return" policy - Begin a movement in India" here
Ha ha ha @Pratyush J … you are already hitting the rock bottom with this movement 🤣
 
Last edited:
Im using a F5 turbo based class A amp from First Note Labs to drive Harbeth P3ESR.
 
I believe an amplifier being " Class A " is too simplified as far as being an ideal design - as people are guessing / speculating - consistently in this thread.

There are seemingly several other design considerations, that make for a best possible sounding amplifier design.

The use of feedback, VS: zero feedback, is one other ultra important criteria. Solid state amps MUST use some Negative Feedback. Not necessarily so however, in the best tube amplifier designs.

I have been told, by sharp circuit people, that whereas PASS solid state amps advertise " No feedback loops ", which is true, Nelson Pass ( and other ) solid state designs need to incorporate " nested " feedbacks, from one stage to another.

I have had two good friends in the USA who purchased and built Nelson Pass " ACA" or "Amp Camp" kits. They each did a proper break in, using high efficiency ALTEC or GPA speakers.

After sufficient break - in, ........BOTH of my friends independently decided - to sell - off their ACAs on eBay.

Their PASS amps could not compete satisfactorily with their existing two stage Directly Coupled tube amps, of special design.

Jeff
 
Last edited:
I believe an amplifier being " Class A " is too simplified as far as being an ideal design - as people are guessing / speculating - consistently in this thread.

There are seemingly several other design considerations, that make for a best possible sounding amplifier design.

The use of feedback, VS: zero feedback, is one other ultra important criteria. Solid state amps MUST use some Negative Feedback. Not necessarily so however, in the best tube amplifier designs.

I have been told, by sharp circuit people, that whereas PASS solid state amps advertise " No feedback loops ", which is true, Nelson Pass ( and other ) solid state designs need to incorporate " nested " feedbacks, from one stage to another.

I have had two good friends in the USA who purchased and built Nelson Pass " ACA" or "Amp Camp" kits. They each did a proper break in, using high efficiency ALTEC or GPA speakers.

After sufficient break - in, ........BOTH of my friends independently decided - to sell - off their ACAs on eBay.

Their PASS amps could not compete satisfactorily with their existing two stage Directly Coupled tube amps, of special design.

Jeff
Hi Jeff,
If you can, kindly enlighten us little more regarding your chosen example of Nelson Pass ACA.
What was the purpose of ACA design?
Who were the original target users?
And
Out of so many different Nelson Pass designs of DIY classA amps, why did Both of your friends choose ACA? What was their thought process while finalizing ACA, discarding other more popular designs like F5, F6, Alephs, M2 etc.

Regards
 
I have been shopping for speakers for some time and had listened to Platinum and Diamond Achals with Saptak at Indiqaudio. I had shared the feedback with Amit that Diamond's are fatiguing with Saptak. When the Class A amp came together, he invited me to come in and listen to Diamond's with Class A. I did a 1.5 hr audition session with the combo and what a change it was! Diamond's were no longer fatiguing and were really smooth. I had found Platinum's slightly lacking in bass and with this combo, I have the combo of heft and scale in the same set up. I have booked a Class A with Diamonds.
 
Hi Jeff,
If you can, kindly enlighten us little more regarding your chosen example of Nelson Pass ACA.
What was the purpose of ACA design?
Who were the original target users?
And
Out of so many different Nelson Pass designs of DIY classA amps, why did Both of your friends choose ACA? What was their thought process while finalizing ACA, discarding ot


My two friends bought an ACA because it was inexpensive and they each wanted to try it out, VS their highly developed 2A3 amps ( SE, DCed, LSES power supply ).

I would guess the purpose of the ACA is for Nelson to have an affordable product with which he can make money.

One of these two friends knows Nelson personally. He and Nelson occasionally talk amp circuits on the phone.

The use of nested Feedback is likely inherent in all of these Solid State designs Nelson does, independent of Model Designation.

Each of my friends independently came to the conclusion ( that their ACA needed to be sold to someone else ), and they kept their particular tube designs. Their tube amps have zero Negative Feedback, and all the other benefits inherent in their amps' unique design.

One has to look no further than the 2021 6005 stereo DIY amp thread on HFV, to discover an amp that exceeds those 2A3 amps the two fellows were using as a reference. I have personally heard all three amps.

One will NOT find these three amp's inherent design benefits, in other tube amplifiers currently existing.

Additionally, I personally think 2021's HFV 6005 stereo DIY amp out-performs their two 2A3 monoblock amps, and all-else existing world-wide, ...... and does so rather easily. ( For many good reasons, all previously provided. ) That..... is just my best guess.

Please make no mistake - when judging me and / or what I claim herein.

101 dB speakers, and higher, are required to play in this league. Mine are about 103 dB, Professional, not consumer quality.

Have fun, I sure am.

Jeff
 
Last edited:
Check out our special offers on Stereo Package & Bundles for all budget types.
Back
Top