ICEpower 50asx2 modules

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The short version is no, you probably don't need buffering.

The longer version is that you might like how it sounds anyway. If you have a balanced source you either need two SE-buffers (mine would work, but plenty of other options :) ) or you need something that is designed to be balanced. I've done one example with the OPA1632 opamp (here), but again there are several designs out there.
 
Haha, I can decode message #47.

"I used modules SE BTL mode. Need ustonovit moschny jumper between two negative outputs of the module.
In its implementation of the buffer I applied on the lamp fahoinvertor Lundahl transformer.
Impressions are the best."

Means

"I used modules SE BTL mode. Need install massive jumper between two negative outputs of the module.
I made tube input buffer with transformer (sounds like tube input stage and transformer acting as phase inventor)
Impressions are the best."
 
Hi,

I have 2 50ASX2SE modules lying around and I would like to know what's the definitive opinion regarding the SE to BTL mod.

I've read Nisbeth blog and it seems the it is very easy to do it. Of course you would need a balanced input, but it only requires to desolder one jumper!

On the other hand, post #108 post an official ICEpower reply saying that the mod would not work properly.

So... is it worth it or not?

Also, is there any "already assembled" input buffer board I could buy that works properly with the 50ASX2SE (if I decide to run single ended input, as I asume i don't need buffer when running balanced input)??
 
Hi,

I have 2 50ASX2SE modules lying around and I would like to know what's the definitive opinion regarding the SE to BTL mod.

I've read Nisbeth blog and it seems the it is very easy to do it. Of course you would need a balanced input, but it only requires to desolder one jumper!

On the other hand, post #108 post an official ICEpower reply saying that the mod would not work properly.

So... is it worth it or not?

Also, is there any "already assembled" input buffer board I could buy that works properly with the 50ASX2SE (if I decide to run single ended input, as I asume i don't need buffer when running balanced input)??
The slowdiyer has tried this check here ICEpower 50ASX – SE to BTL conversion | theslowdiyer
 
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Hi,

I have 2 50ASX2SE modules lying around and I would like to know what's the definitive opinion regarding the SE to BTL mod.

I've read Nisbeth blog and it seems the it is very easy to do it. Of course you would need a balanced input, but it only requires to desolder one jumper!

On the other hand, post #108 post an official ICEpower reply saying that the mod would not work properly.

So... is it worth it or not?

Also, is there any "already assembled" input buffer board I could buy that works properly with the 50ASX2SE (if I decide to run single ended input, as I asume i don't need buffer when running balanced input)??
The slowdiyer has tried this and says it works fine. ICEpower 50ASX – SE to BTL conversion | theslowdiyer
 
The slowdiyer has tried this and says it works fine. ICEpower 50ASX – SE to BTL conversion | theslowdiyer

He said: "I haven’t actually measured anything (not sure what to measure to be honest) but I get clean audio out on the BTL speaker connector (P104) and a very loud buzzing noise on the other output, so at least it isn’t running stereo anymore. No guarantees on anything yet though, but it’s definitely promising."

Icepower said: "Using the SE module in BTL mode will cause Bad audio performance in BTL mode with high distortion (since the two channels are not switching in sync as they should when running in BTL, because they are designed for SE mode – Also the two common mode chokes will not work (bad EMC performance)."

I think one thing is to get sound in one end, and the other is to get proper performance.
 
He said: "I haven’t actually measured anything (not sure what to measure to be honest) but I get clean audio out on the BTL speaker connector (P104) and a very loud buzzing noise on the other output, so at least it isn’t running stereo anymore. No guarantees on anything yet though, but it’s definitely promising."

Icepower said: "Using the SE module in BTL mode will cause Bad audio performance in BTL mode with high distortion (since the two channels are not switching in sync as they should when running in BTL, because they are designed for SE mode – Also the two common mode chokes will not work (bad EMC performance)."

I think one thing is to get sound in one end, and the other is to get proper performance.
This is the reason ICEPower take out the speaker unused speaker connector on the BTL model. You will notice that ICEPower do not quantify the extra distortion. However I do take your point about measurement.
 
As mentioned several times you're right that I haven't measured anything so I can't prove my theory, however I am not the only one who has done this mod and claimed it a success.

Also, I am 99.x% sure that the ICEpower reply refers to bridging without moving the BTL-jumper, because I believe the BTL jumper is what syncs the channels (like the BTL-sync pin on the 125ASX). If you can verify poorer EMC-performance on a converted module you can always remove the choke, but I don't have a way to test for EMC so I did not bother doing that.

Last but not least: As I've written somewhere else that I know for a fact that the reason that there are two versions of the 50ASX was that omitting parts on the BTL version made it a bit cheaper and thus a candidate for going into small subwoofers etc. However, I don't know whether that translates to any other (minor) design changes other than omitting the superfluous components. The first (non-production) modules were convertable like the 125ASX and in exactly the same form factor as the ones sold now.
 
Hello All, Here's my 2 cents worth about the SE to BTL conversion (as I also posted on Nisbeth's slowdiyer):

Just a couple of FYIs: I just replaced a BTL version with a converted SE (just changed the W40x jumper) in my Gallien Krueger MB115 bass amp and it seems to work. Double the voltage across P104 vs. each side to Ground, but I haven’t listened to it yet or made any measurements. The W40x jumper is what reconfigures the outputs so that they both appear on P104. I don’t think it has anything to do with the sync.The only other difference I could see between the two types is that the BTL has a 560 ohm sm resistor in the middle of the group of sm components between IC400 and IC401-402 whereas the SE has a resistor which is marked with what seems like a 0 (it’s a tiny square). It also looks like the 560 ohm was hand soldered, as was the jumper .Maybe a clue about the difference.
Hope this is useful to someone.
Cheers, David


Next day:
A couple of further things: I measured the two resistors in question and they are, in fact, 0 and 560 Ohms. Also, I looked at the magnified photos of both types on eBay,etc. and they all correspond to what I saw with my two amps. At least on the top side. I couldn’t find any clear enough photos to check the back side and I already installed the converted SE amp in my bass amp and don’t feel like taking it out again (right now anyway). :)
Annoyingly, for me anyway, the BTL version is now widely and cheaply available (eBay, PartsExpress, etc.). I bought the SE a while ago and procrastinated installing it.

Cheers and Happy Holidays, David
 
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