Amp Camp Amps completed

[vbutani]

I completed my two ACA kits and put them into service. Move aside Elekit TU-8200. For me they seem wonderful in bridged mono mode driving my Klipsch Heresy IIIs. A lot more clarity.

I had expected my daughter with super sensitive ears to scream when I played music but Klipsch seem to be tame with these amps. No horn shout or fatigue.

Set them up on my rack and rewired the system. CDP + Tape + DAC > Elekit TU8500 preamp > 2 x ACA Bridged Mono > Klipsch Heresy IIIs is the chain.

View attachment 69257

Now @rajan- had asked me how ACAs performed when used with Elekit TU 8500 preamp. I had to compare with something. Since there is no volume control, CDP could not be connected direct to ACAs. So used the headphone out of CDP to connect to ACAs with the HP level control acting as volume control. Played the same song (Lucky Ali - Tere Mere Sath mein hotha hai) in both setups and did a crude measurement of the spectrum on my mobile app SPL meter. See below screenshots.

The same song played in both cases for nearly the same time at about the same average level and SPL meter set to measure the spectrum for the same time in both cases. NOTE THE PEAK LEVELS recorded for each Octave. This app indicates the peak hold. My thinking is the peak measured for the same song playing at about the same level over the same time period should give an indication of the system performance.

It is not calibrated or a much sophisticated measurement so please take it only as a rough guidance to the performance. If there is a more accurate but economical way of measurement please advice.

View attachment 69258
With Elekit TU-8500 driving the ACAs you may note the whole spectrum is a couple of dB roughly lower (Y axis major divisions could be seen on zooming in) the direct from CDP.

For the ears direct from CDP seemed a bit more clear but also a little sharp. Through the preamp it was sweeter and relaxed. Imaging is neck to neck but Elekit has an edge.

Hope this helps.

As I am planning to make chasis for ACA amp, I have some queries as follows:-

1. External dimensions (H x W x L) of ACA amp in mm
2. Internal dimensions (H x W x L) of ACA amp in mm
3. Do ACA amp has enough internal space to accommodate Toroidal transformer of height 50mm and 110 mm diameter. I think one more pcb needs to be added for capacitance

As I couldn't find these details on diy store site and forum, I really appreciate if it's possible for you to share these details.

Thanks

 

[Subbu68]

As I am planning to make chasis for ACA amp, I have some queries as follows:-

1. External dimensions (H x W x L) of ACA amp in mm
2. Internal dimensions (H x W x L) of ACA amp in mm
3. Do ACA amp has enough internal space to accommodate Toroidal transformer of height 50mm and 110 mm diameter. I think one more pcb needs to be added for capacitance

As I couldn't find these details on diy store site and forum, I really appreciate if it's possible for you to share these details.

Thanks

The ACA chassis is based on 2U Mini Dissipante chassis. https://diyaudiostore.com/collections/amp-camp-amp/products/amp-camp-amp-chassis look for the link on this page.

If you spend some time on diyaudiostore website you can get all the details you need. It is not a straightforward website though. They give links to nearly every info you need whether on the circuit, mechanical parts or building.

The whole chassis is practically empty. Not sure a 50mm height transformer will fit in as 2U height is 75mm but you add the fitting bolts, nuts etc. of the trafo you may need 3U height. Even if the trafo may fit in the 2U chassis I would not use it since the access the boards is already limited. In future if there is a need to dismantle the boards fixing the trafo may make life difficult.

Not sure if someone has implemented this in HFV.

 

[vbutani]

The ACA chassis is based on 2U Mini Dissipante chassis. https://diyaudiostore.com/collections/amp-camp-amp/products/amp-camp-amp-chassis look for the link on this page.

If you spend some time on diyaudiostore website you can get all the details you need. It is not a straightforward website though. They give links to nearly every info you need whether on the circuit, mechanical parts or building.

The whole chassis is practically empty. Not sure a 50mm height transformer will fit in as 2U height is 75mm but you add the fitting bolts, nuts etc. of the trafo you may need 3U height. Even if the trafo may fit in the 2U chassis I would not use it since the access the boards is already limited. In future if there is a need to dismantle the boards fixing the trafo may make life difficult.

Not sure if someone has implemented this in HFV.

Thanks Subbu sir, I already visited it, but there was no mention of total width including heatsinks.
I guess they use 40mm heatsinks so if total width is around 200 mm including 80mm heatsinks than there is very less space left in internal chasis.
For height, I think you are right; I may have to go with 3U height size for considering future updates.

 

[Subbu68]

Thanks Subbu sir, I already visited it, but there was no mention of total width including heatsinks.
I guess they use 40mm heatsinks so if total width is around 200 mm including 80mm heatsinks than there is very less space left in internal chasis.
For height, I think you are right; I may have to go with 3U height size for considering future updates.

No Sir, it is there. No need to guess anything. As I wrote, with a patient reading all details could be found there.

There is also a PDF explaining the measurements on Mini Dissipante product page.

 

[vbutani]

No Sir, it is there. No need to guess anything. As I wrote, with a patient reading all details could be found there.

There is also a PDF explaining the measurements on Mini Dissipante product page.

Thanks sir, I will go through it again.

 

[rajan-]

Having done and dusted the ACA pair, two more equipment to the "family". Had to shift and shove the stuff around. More power cables, more speaker cables, inputs... It was a mess behind the rack. Sunday afternoon work... Tidied up...
From this
View attachment 69329
To this , power bricks of ACAs behind TV, back side of the rack was a bit messy too till a few hours back.
View attachment 69330
So tidying up the back all wires pulled down, new trunking fixedView attachment 69331
The final ..power bricks of ACA mounted on the back, power cables and wires tidied up...
View attachment 69332
View attachment 69333
View attachment 69334
From the front
View attachment 69335
The inputs for subwoofer has to be wired...later

@Subbu68 Any chance to try & experience with Parallel mono setup ?

Now that I have the Sub working quite well, I am thinking abt giving it a go.

Read in few places that Bass may be a bit thin, but all else is supposed to sound better than Bridged mono.
That may not be an issue if you have the Sub augmenting the bottom end.


BTW, what are the big speakers hiding in the corners and the white square lunch box on the top shelf ?

Note: My cabling is still a spaghetti noodle mess.
I got a decent audio rack second-hand, found it on FB Market place, and the owner turned out to be the the guy running DIYaudio store. didnt know he was a just couple of Km away... He gave me a small (further) discount when I told him abt my ACA. lol

 

[Subbu68]

@Subbu68 Any chance to try & experience with Parallel mono setup ?

Now that I have the Sub working quite well, I am thinking abt giving it a go.

Read in few places that Bass may be a bit thin, but all else is supposed to sound better than Bridged mono.
That may not be an issue if you have the Sub augmenting the bottom end.


BTW, what are the big speakers hiding in the corners and the white square lunch box on the top shelf ?

Note: My cabling is still a spaghetti noodle mess.
I got a decent audio rack second-hand, found it on FB Market place, and the owner turned out to be the the guy running DIYaudio store. didnt know he was a just couple of Km away... He gave me a small (further) discount when I told him abt my ACA. lol

With parallel mono the power to my 8ohm speakers is going to be 8W. Same as Elekit tube amp.So have not tried it.

Those two behind Heresys are the Ahuja FRs on cardboard OB. Wife and daughter have been pressing me to get them on a wood baffle. My Wood working skills are rudimentary and no space to do it as we are apartment dwellers. Have to get a carpenter but COVID has risen here and going to the industrial area is risky.

Wish I had looked for Ahuja 12FRX before splurging on Klipsch. Never knew there were stores in Dubai selling drivers from Eminence, Ahuja etc. With the sub they are just wonderful.

That lunchbox is the IPTV STB from the local telecom co.

 

[rajan-]

With parallel mono the power to my 8ohm speakers is going to be 8W. Same as Elekit tube amp.So have not tried it.

Those two behind Heresys are the Ahuja FRs on cardboard OB. Wife and daughter have been pressing me to get them on a wood baffle. My Wood working skills are rudimentary and no space to do it as we are apartment dwellers. Have to get a carpenter but COVID has risen here and going to the industrial area is risky.

Wish I had looked for Ahuja 12FRX before splurging on Klipsch. Never knew there were stores in Dubai selling drivers from Eminence, Ahuja etc. With the sub they are just wonderful.

That lunchbox is the IPTV STB from the local telecom co.

Do you crank it up on the pre to get the desired volume levels on the heresy ?

I have no experience with Klipsch Heresy, but I thought they are very high efficiency designs.

 

[rajan-]

All along, I was using the Amp Camps in Bridged Mono, and I couldn't turn up the volume on the pre amp at all, not even 10%, or too much gain.

Although The performance at low volumes was magical, I was thinking my system was becoming a one trick pony. Phenomenal with a bit of relaxed music, but If I throw in something heavy, it was getting a bit un-bearable (Plus the high gain was making this worse)

I thought its because of the Full Ranger not ideal for such music, and was (May be) too scared to upset that performance levels where it was so good.


Thinking back, it should have been obvious ..

the ACA in Parallel Mono just solved one of my biggest problems.


1. I can easily go past 12 O clock on Volume control (details which were missing out at low volume levels are now out in the open in its full glory)
2. No Distortions at higher volume (much higher damping factor in parallel mono). The control on the full rangers have gone up to a level, its almost unreal. The difference is massive.
3. Now I can play really busy music. no issues
4. The attack, the presentation.. cant believe the transformation.

I don't think I am going back to Bridged Mono ...

 

[Subbu68]

All along, I was using the Amp Camps in Bridged Mono, and I couldn't turn up the volume on the pre amp at all, not even 10%, or too much gain.

Although The performance at low volumes was magical, I was thinking my system was becoming a one trick pony. Phenomenal with a bit of relaxed music, but If I throw in something heavy, it was getting a bit un-bearable (Plus the high gain was making this worse)

I thought its because of the Full Ranger not ideal for such music, and was (May be) too scared to upset that performance levels where it was so good.


Thinking back, it should have been obvious ..

the ACA in Parallel Mono just solved one of my biggest problems.


1. I can easily go past 12 O clock on Volume control (details which were missing out at low volume levels are now out in the open in its full glory)
2. No Distortions at higher volume (much higher damping factor in parallel mono). The control on the full rangers have gone up to a level, its almost unreal. The difference is massive.
3. Now I can play really busy music. no issues
4. The attack, the presentation.. cant believe the transformation.

I don't think I am going back to Bridged Mono ...

Thank you for the feedback..i will have to also try this.

Had read somewhere about a compensation circuit for FR speakers with ACA. Searching for it.

 

[rajan-]

Do an AB with Ahuja and Heresy on both Parallel and bridged mono.

If I would hypothesize, with the additional Damping capability in parallel mono setup, the 12inch ahuja drivers should be better controlled .

 

[Subbu68]

The perceived difference for me is a reduced bass, less loud and less shouty with parallel mono - less power and being OB. Trial on...

 

[Subbu68]

The in-house experts in music say Bridged mono is better clarity. Heresys were not so good with ACA so wired them to the tube.

Another issue with parallel mono is the infamous "fart" of ACA when powering up.

On bridged mono I had eliminated it by sequential switching of the system with a IFTTT switch Sonoff 4 Way. 1 way each for Source+preamp, subwoofer, Elekit tube and ACA.

Source + pre > 33sec > ACAs (Elekit tube) > 5sec > Subwoofer

Reverse with lower delays for switching off.

Wiring in parallel mono brings back that switching surge back.

 

[rajan-]

My Pre is a NP design, and being solid state will be making the sound different to the Tube Pre that you have.

And your both set of speakers are VERY different to the one I have.

To confirm if its placebo effect, I moved back to Bridged mono, and can confirm I am now preferring the Parallel mono setup.

now that I know what I have and like, I am going to make it more flexible.

1. Integrate a switchable Tube buffer to the Preamp
2. Now I have the Sub already setup, need to buy the Compression Driver and set that up with the switchable box.

 

[Subbu68]

My Pre is a NP design, and being solid state will be making the sound different to the Tube Pre that you have.

And your both set of speakers are VERY different to the one I have.

To confirm if its placebo effect, I moved back to Bridged mono, and can confirm I am now preferring the Parallel mono setup.

now that I know what I have and like, I am going to make it more flexible.

1. Integrate a switchable Tube buffer to the Preamp
2. Now I have the Sub already setup, need to buy the Compression Driver and set that up with the switchable box.

Something to read on https://www.passdiy.com/project/amp...e-amplifiers-and-sensitive-full-range-drivers

 

[Subbu68]

Those Ahujas being PA design FRs, perform better with lower damping as they are damped down?