Another ACA build coming up

[Subbu68]

you are still on the ifi nano feeding the bridged ACA ?

I am curious to know how the Elekit Tube pre-amp feeding the ACA will sound.

Give me sometime.

Working on to rearrange the connections. Perhaps need to get a Y connector to keep Elekit amp and ACA in the system.

Can easily plug any of my speakers to both amps as I have two sets of spkr wires.

 

[drlowmu]

ACA Unit 2 completed. Took on board the suggestion by @rajan- to the extent possible for now. Further improvement later

Now for powering up and DC balance before burning in. Then the bridge mode with Unit 1 for one channel and Unit 2 for the other. Unit 1 had blue LEDs and Unit 2 red ones to differentiate

View attachment 69182

SUGGESTION :

Once your two ACA amps are broken in, untwist the input wiring on one of them, both channels, so that the two wire polarities from the RCA input jack to each PC board, do not touch each other one time. Then, compare the two amps.

Each twist is an increase in capacitance, and it is audible on a well set up system. Same applies for the speaker leads, amp to crossover, crossover to driver. And the interconnects. ALL polarities should kept separate for best audio / listening performance.

A free audio performance upgrade . Listen carefully, one amp ( and separated polarity channel wiring ) VS: the other when twisted, easy to do.

Jeff

 

[Subbu68]

you are still on the ifi nano feeding the bridged ACA ?

I am curious to know how the Elekit Tube pre-amp feeding the ACA will sound.

Done for you and is quite good. Temp connection to Elekit preamp.

Check if you can see the videos below. YT says copyright infringement. Not sure if it will play for you..a sample with Elekit TU 8500 and Denon CDP in bridged mono and stereo modes. Listen with a headphone. They are recorded using phone.

In reality I could feel the difference between the two modes. Definitely clarity is more in bridged mono. And as my daughter commented when I drove with iFi DAC direct, ACA is clearer than my Elekit TU 8200.

 

[Kannan]

Why not build a better PSU for the mono blocks?

 

[Subbu68]

Why not build a better PSU for the mono blocks?

Yes, that is the next work. Have to cool off this impact on the purse

I will source the trafo etc.in India when I go next time. It is really expensive here in UAE. All imports.

Which supplier do you recommend for trafo?

And are keltron still making good caps?

 

[Kannan]

Yes, that is the next work. Have to cool off this impact on the purse

I will source the trafo etc.in India when I go next time. It is really expensive here in UAE. All imports.

Which supplier do you recommend for trafo?

And are keltron still making good caps?

There are quite a few. There is one guy in Chennai, but I normally buy from Torotrons (Pune) by habit (stuff is very good), then Silchar Technologies which is quite famous. I have heard some very good ones in Calcutta (dont remember names) same in Kerala also as these two places that have quite a few tube amp builders.
Maybe the more experienced and regular amp builders in the forum can chime in better

 

[Subbu68]

There are quite a few. There is one guy in Chennai, but I normally buy from Torotrons (Pune) by habit (stuff is very good), then Silchar Technologies which is quite famous. I have heard some very good ones in Calcutta (dont remember names) same in Kerala also as these two places that have quite a few tube amp builders.
Maybe the more experienced and regular amp builders in the forum can chime in better

Is Precision in Chennai still in business? We used to get current and voltage transformers (protection and measurement), variacs etc.when i worked in L&T several years ago.

 

[Kannan]

Yes, that is the next work. Have to cool off this impact on the purse

I will source the trafo etc.in India when I go next time. It is really expensive here in UAE. All imports.

Which supplier do you recommend for trafo?

And are keltron still making good caps?

these amps sound fabulous in SMPs supplies itself (I was powring mine with a laptop adapter with power going through a capacitance multiplier).
I did buid a linear 19.5 volt supply for a laptop, but when used with the AmpCamp it sounded a bit restrained (Unregulated should be better for amps), so I prefered the laptop brick.

 

[Kannan]

Is Precision in Chennai still in business? We used to get current and voltage transformers (protection and measurement), variacs etc.when i worked in L&T several years ago.

yes...same guy I was talking about. After Covid I contacted him, but he was not interested to take small orders. So I went back to torotrons after he opened up some 3 months later.

 

[Subbu68]

these amps sound fabulous in SMPs supplies itself (I was powring mine with a laptop adapter with power going through a capacitance multiplier).
I did buid a linear 19.5 volt supply for a laptop, but when used with the AmpCamp it sounded a bit restrained (Unregulated should be better for amps), so I prefered the laptop brick.

Was it having enough headroom? As you know ACA efficiency is quite low. These new bricks from Meanwell are at 24V, 5A. I calculated them to take around 150VA input.

I am planning a 2x 24V, 2x 200VA output PSU for the two units .

They do sound insane with Meanwell 24V brick. No way to compare unless i can build a linear PSU.

 

[Kannan]

Was it having enough headroom? As you know ACA efficiency is quite low. These new bricks from Meanwell are at 24V, 5A. I calculated them to take around 150VA input.

I am planning a 2x 24V, 2x 200VA output PSU for the two units .

They do sound insane with Meanwell 24V brick. No way to compare unless i can build a linear PSU.

With all digital sources where the output is around 2 volts minimum there is absolutely no problem. My Teac has a in build preamp with very little gain of its own was a perfect match for the AmpCamp. High gain pres will overdrive the AmpCamp if source output is 2 volts.
You will need a high gain pre for AmpCamp only with low gain sources like turntables and cassette decks are used.
With Teac DAC/pre and AmpCamp I could get enough play on the volume control so that I could set lower volume levels depending on the ambient noise without loss in details across the bandwidth.

 

[grindstone]

If you guys do build more linear psus, please start thread(s) because it's of interest.

 

[Subbu68]

With all digital sources where the output is around 2 volts minimum there is absolutely no problem. My Teac has a in build preamp with very little gain of its own was a perfect match for the AmpCamp. High gain pres will overdrive the AmpCamp if source output is 2 volts.
You will need a high gain pre for AmpCamp only with low gain sources like turntables and cassette decks are used.
With Teac DAC/pre and AmpCamp I could get enough play on the volume control so that I could set lower volume levels depending on the ambient noise without loss in details across the bandwidth.

Learnt something new, seriously saying. I was always thinking the output of the sources are all standardized to ~2V.

 

[aeroash]

Some of you who are keen to try the ACA and have been put off by shipping and duty costs, here's an alternative, provided you hold a valid IEC.



When I enquired about the insane costs of importing the ACA kit I was offered the following response from the DiyAudio Store.

Please email the helpdesk ([email protected]), and we will obtain a custom quote for non-DDP shipping. You will then be responsible for paying the duties yourself, and as you say, you "should" be taxed at the rate you say.

We have been having trouble with the duty calculation, and actually lost many, many thousands of dollars earlier in the year due to underquoting on duty compared to what various countries actually ended up charging us. India (and Barbados) are the two most extreme countries for lumping us with rampant duty overcharges, so what you're seeing built into the price in your screenshot is a buffer to balance out the typical losses moving forward.

I agree with you that this situation has become rather untenable. As such, we are in the process of totally revamping all the stores systems and shipping methods and calculations systems, back-end inventory systems, front-end, everything.

One of the changes that will be implemented shortly is stopping offering DDP (delivered duty paid) services. We may offer it again in the future, but for now the burden on us to calculate duties and then pay whatever the destination country decides to charge us has not been working out very well for us (or, as you see, for you, when buffers are applied).

So what will happen in the near future is we will continue offering DHL Express, but not DDP. It will be DDU (Delivered Duty Unpaid), and the responsibility of duties will fall on the receiver. Now this is a bit more risky for us in some ways, because if a receiver decides to reject a package, we'll be lumped with the cost of sending the goods there, and returned back. But it's the best we can do, and if we have a significant number of returns from any particular country we will have to stop offering shipments to those countries altogether.