SDA-400 Professional multi-way

[AP2]

Hi,
@Nikola:
I'm not one that follows the "colored stones or sticks" but there is a simple explanation. A first change of the sound in the first 3-4 days of listening, is due to electrolytic capacitors. these amplifiers were shipped right away after only one start for testing (in practice 15 min of operation, from total virginity).
----------------
As it is a "promotion test," I preferred to limit the current output of smps. then you can replace a res (not SMD) very simple (or adding welded on the bottom side of the PCB), to have a comfortable listening volume, with greater depth on the bass or drums.
produces no other changes on the tone of the sound.
-----
...Without the old thread ... we lost your nice sofa hehe!

Regards

 

[Forane12]

Well, let's say I do hear a difference in power cords but I find no difference with Mpingo discs on amplifiers(definitely hear a difference on cartirdges though and it is obvoius why). What is the resistor that needs to be changed, I do want to try that too?

I will repost the picture as soon as I get home, I don't have time to go and buy a new camera so all the pictures that you will see are from my iPad, apologies for the bad quality.

Here is a link to the spearers I had on hand to try with the amps, unfortunately no pictures of the 2.3BF in action with the MDA400... 🙁

Exproject - ???????

 

[AP2]

Well, let's say I do hear a difference in power cords but I find no difference with Mpingo discs on amplifiers(definitely hear a difference on cartirdges though and it is obvoius why). What is the resistor that needs to be changed, I do want to try that too?

I will repost the picture as soon as I get home, I don't have time to go and buy a new camera so all the pictures that you will see are from my iPad, apologies for the bad quality.

Here is a link to the spearers I had on hand to try with the amps, unfortunately no pictures of the 2.3BF in action with the MDA400... 🙁

Exproject - ???????

In your nice link, there is more than one pair of speakers I'd like to have in my living room. currently I stopped with a pair of new B & W 802 II. for may jazz. 🙂
returning to Resistor,if it is added below, the value must be 330R 1/2 watt metal oxide (no carbon).
Increase SIN right at 1kHz, 18W (4R) but up to 30W with burst at 4R. so the difference is great, listening
In the evening I put the photo of the location of the resistor.
(When use iron solder, disconnect all cable from MDA-400)

 

[pinnocchio]

So there's two resistors we are talking about here?

One to limit the current of the PSU which can be bypassed and the other one if for what exactly?

Can we have pictures of their locations?

Thanks
Do

 

[Forane12]

🙂 you can also see my Linkwitz Plutos in one of the pictures, I regret selling them and I am considering buildin a new pair...

Please make some pictures of the resistors, will be of great help...

 

[AP2]

Hi,
Perhaps for some it is easier to solder a resistor at bottom (in parallel).
Specify that this is not a modification, the mda-400 return in original as default. therefore do not alter the reliability. will continue to operate the current-limiting in amplifier, and the smps, short-circuiting included.

A) If replace the resistors, the new value is 150R metal oxide
B) if you add in parallel at bottom, the value is 330R metal oxide

Important: disconnect all cable, input etc.. from mda when use iron solder.

@Pinnocchio:
You not need add or change res. 🙂

 

[pinnocchio]

Got it!

Thanks
Do

 

[Forane12]

The resistor was changed and I report that for me it is a good step up in performance so please guys, do yourself a favor and change it or solder the second MOX on the bottom.

I decided to exchange it and made my life quite difficult, the space is not much and I had a friend with desoldering station remove the cap that is close and we tried several MOX resistors before I found one that would fit. And in my case there was another small resistor that is not in the picture above(smaller and kind of grey in color, the one you have to change is R81, it is red and is almost under the transistor, a bit bigger, has another hole close to the leg).

So if I have to do it again I will just solder the suggested value under the board. For me there was no need to go back and compare - Roberto will hate me but I will advise everybody to listen to the MDA400 with the 150R resistor in place, the difference is very obvious. Just be careful with the soldering and take precautions.

 

[danny_66]

Does the DPA-400 amplifier also have a current limiter that can be bypassed with changing a resistor ?

 

[AP2]

Does the DPA-400 amplifier also have a current limiter that can be bypassed with changing a resistor ?

Hi, thanks Nikola, for sharing your test.

This simple change, do not bypass the limiter in MDA-400, just back as default with 150R.
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The DPA-400-Fx has an active system of dynamic power control "APC", there is nothing to change.
For me, the benefits it can provide are already extreme, perfectly comparable with really big class AB in terms of resolution and dynamic.
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Returning to the multi-way 2 & 4CH, today I can put photos. there are some changes on the program, I can provide everything you need, including special wire, AL parts etc, but only as kit (I'll show the fully mounted version).
I will possibly three kits. this is a .. madness that I have the pleasure of sharing. 🙂

Regards

 

[tinitus]

Hi, Roberto, so for my bass guitar, maybe I better not change anything ?

 

[AP2]

Hi, Roberto, so for my bass guitar, maybe I better not change anything ?

Hi,
You can,it's better just for guitar bass, but check well this resistor (see photo of pcb) maybe is already correct (150R).

 

[tinitus]

... but check well this resistor (see photo of pcb) maybe is already correct (150R).

1. and 3. are hard to read, and look more like army green
but probably grey or brown
but grey does not seem to fit in anywhere
2. is green

gold is tolerance 5%
maybe 1. and 3. are both brown
brown, green, brown would make 150 ohm

with flashlight horisontal from the side 1. and 3. color looks very brown to me

so 150ohm it is

thanks Roberto

still mounting connectors, and painting front

 

[AP2]

1. and 3. are hard to read, and look more like army green
but probably grey or brown
but grey does not seem to fit in anywhere
2. is green

gold is tolerance 5%
maybe 1. and 3. are both brown
brown, green, brown would make 150 ohm

with flashlight horisontal from the side 1. and 3. color looks very brown to me

so 150ohm it is

thanks Roberto

still mounting connectors, and painting front

yes, you have 150R,i checked paper of final test.
I remember your use as guitar bass amp.
when ready,test well your ..big string eheh!
Also, I insist for switch off alc in your pre (if you can), just for try
the dynamics with my alc. (has been studied in a recording studio with big name bass-man) only the number one in the world of bass guitar amp, they have my alc.
Sorry, I can not say the name of the company ... but not too far from me.. 🙂

 

[tinitus]

😀

Also, I insist for switch off alc in your pre (if you can), just for try

what is alc ?

ahh ... automatic level control

ehh ... another word for compressor ?
are you saying there is built in compresor in my amp module ?

but I only use one or two jfets feeding solid state power amp, nothing more, no effects

 

[AP2]

😀

Also, I insist for switch off alc in your pre (if you can), just for try

what is alc ?

ahh ... automatic level control

ehh ... another word for compressor ?
are you saying there is built in compresor in my amp module ?

but I only use one or two jfets feeding solid state power amp, nothing more, no effects

Ahahahh! you are very sympathetic, maybe you're English ..? 🙂
No, you do not have a compressor in your MDA-400.
You have a anticlip well researched and very dynamic, which operates only in the area close to the clip.
But it is impossible to make full use of the enormous dynamic performances of the bass guitar without an ALC fast.

 

[tinitus]

You have a anticlip ...

ahh, nice 🙂

backplate almost finished

 

[AP2]

ahh, nice 🙂

backplate almost finished

woW! I hope not connect 3 speakers hehe!
you did an amplifier, multi use, very practical, as I see it.
when we turn on?

I'm curious to know .. PinkMouse? mj777? caffèNoir?

 

[AP2]

New DPS-600

hi,
I am that some expect this smps, then use this thread for info.

This version replaces the DPS-600 (already used the same circuit linear regulator with fast response of the DPS-500)
alignment for the production, it is agreed to use at this point, the same pcb. performance remains in the origin of the DPS-600, slightly better for higher filtration capacity. Power-Unit remained unchanged.

To offer a very competitive price and oriented class AB, were removed the following functions:
No voltage output for Class D driver.
No AL bottom plate.
Available only from + /-36V to 45V (ADJ trim on board +5 V) and AUX + /-20V LC filtered unreg. 2x250 mA.
Power output 500w (12A;16 Amp repetitive peaks
Remote control yes.
Notes: Aux may be required up to + /-90V.
Special price 120€
many already know, the performance of this smps for audio.

regards

 

[AP2]

KIT-1 (2x300w@4R) SDA-400 Dual Mono

Hi,
Kit includes all for assemble in your 1U case:
Spacers,screws,components for PBTU-3 and input board.
Components/materials as shown in photo.
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Amplifier and smps well known, absolutely free of defects.
A little tuned dps-400 for this application. (from new release)
I can only offer 20 kits, one at price of € 200+22 for spedition.
40 € per piece about...😱

This amplifier, complete with aluminum parts, will be available on the shop AudioPower at € 395 + VAT + Delivery.
-----------------------------------------
I hope you look good, not like a chip class D (without manufactory, right smd i mean, so ultra low price of production).

Happy listening.

P.S. 20 Kit ready.
DPS-400 for this kit,pcb blue.
Regards