Bargain Lab Gruppen E4:2 - £100 for 2 x 200W ....

LittleNipper

Well-known Member
Updating the initial post so you might be able to get a deal. To surmise, I'm now running these amps driving LCR MK Sound MP150's and can't tell any difference to either my Denon X3500 or Crown XLS 1502's. I had purchased these for Atmos hight duties which is where they will end up.

After the FAN mod ( details below ) £12 it's pretty darn quite ( 36db ) when running.

Due to being able to set a noise floor before enabling a channel it means no hiss / noise when no sound / idle with instant on. Attenuation on the rear allows tweaking whilst setting up with processor or receiver. No buttons on the front, set and forget.

The review of these on Audio Science Review ( Lab.Gruppen E 4:2 Pro Amplifier Review ) isn't great but is flawed in what/how it's reviewing. Equally, I've bought things on reviews from this web site and not been impressed.

The £100 one I got was from one seller on ebay that one was new but ended up knocked about - thus cheap. I have since purchased from a chap ( www.ebay.co.uk/usr/gregwinton ). I bought another this morning from him ( £116 Inc shipping ). He's put another post up £500 for 5 of them. So, 10 channels of 200W into 8ohms.

He had about 30 of them which he removed from an install ( prob. updating equipment ).

So.... It's do you feel lucky punk time. Hell, on Atmos Height with sensitive speakers it's a no brainer I think...

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I've been having some mad professor time today !!

I've been searching for amps for my height channels I thought I would look outside of the normal box and came across Lab Gruppen E4:2's. Essentially 400W split between two channels. So, 200W + 200W or if you've just got one speaker connected it will auto redirect everything into the one channel, so 400W. I'm not going to get into the technicalities of how it sounds, because I'm not that bright. Other people can perhaps warn me of the perils I face !


You will also see they do :-

E 10:4 - 1,000 into 4 speakers
E 5:2 - 500 into 2 speakers ( 250 + 250 )
E 8:2 - 800 into 2 speakers ( 400 + 400 )
and a few others with more frightening amounts of power.

LOOKS :-

Anyhow, I think they look pretty, very minimalist. They are small too - only 1U. Ah, yes, rack mounts, sorry about that. However, they are do darn good looking, even not in a rack they will look pretty good. I would place them on my processor with pride ! ( you'll need some little pads ).

CONNECTIONS :-

Alas, they are not wired up in a fashion we are used to. Which I don't think is a bad thing, based upon the mucking around I had removing connectors from my processor and amps to play with this new amp.

In-fact, in the case of the speakers, I prefer how they do it. With regards to line-in signal ( from RCA or XLR ) well, it certainly means I won't have a problem wiring in 4 of them in a small form factor. So, yeah, I quite like the inputs too.

The speaker connections are Phoenix 1709047 2 Port connectors (or Anytek KT02015000CCG). Just take your fat old speaker cables and push 'em in and screw them down. Absolutely NO chance of stray wires shorting anything. You can just slide them straight into the back of the amp and it's super nice.

The connectors for the inputs were a tad fiddlier. These are also Phoenix connectors ( Part number MSTB 2.5/3-STZ-5.08 ). However in 10 mins I was able to strip a XLR to RCA connector and convert into a Phoenix to RCA connector with no soldering (but i did need my glasses). Sure, if I was to do it again I would perhaps use fancier cables or perhaps joined the bits with solder. But hell, the end result when using these inputs.... Zero noise. I mean nothing.

NOISE FLOOR :-

Ear right up on my MK Sound MP150's. Ziltch. Now, my Crown XLS 1502's, you can hear a noise floor, even a little from my Denon x3600h.

Anyway I've just done what I said I wouldn't - but hearing nothing is easy to describe. How the noisy bit are... Nah... experts needed.

I plugged the Lab Gruppen into my trusty Denon X3600h for the centre channel running a MP150. I ran a signal test through LCR ( L and R driven by Crown XLS 1502 ). And used a db monitor to get them all the same ( ish +- 0.5 db ). At the rear of the Lab Gruppen was a gain knob. They call it an attenuation with a range from 0 db to -10db. I set it at 11 O'clock. What ever that meant but half must mean I'm not cranking this beast too much.

Now, all the controls are to the rear, so you can't mess it up accidentally. Even the power switch. It auto sense no-signal and goes to low power mode of <1W. Which means I don't care too much about turning the main switch to my rack off.

BASTARD NOISY FAN :-

So, powered it up. Yep... Sounds good to me. Kept up with the Crown's perfectly well..... And then....

You knew somewhere this had to come. The flippin fan kicked in. In a rack it would be fine. But not here, in my lounge. Took the amp to bits, it's a crappy china fan about 39mm by 39mm, so I will have a look for a silent replacement. But for now I've just disconnected it. The thing has thermal protection so not too worried about it over heating. It's been running a movie at -10db for an hour I can't feel any heat on the unit and it's not complained or gone into protected mode.

I will update this thread after I upgrade the fan. If anyone can point me in a decent direction, it would be appreciated.

BANG FOR ONES BUCKAROOS :-

The best thing is... I paid £100 for the first amp NEW! Yep for 2 x 200w. I bought a pair of amps in the end for Atmos height channels, but will perhaps have a little play using them on the lower bed. The second one was second hand, in perfect order for £125. It looks perfect inside, no mess, dust or blown caps.

Interestingly, when I took the amp case off, the attenuation knobs pop off really easily. I think this is so they can be permanently removed to stop fiddling !

So, that was today' fun. I hope you found this info interesting. Just think about it.... 8 x 200 w for £400 ( if you get lucky with your purchases ).
 

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LittleNipper

Well-known Member
To figure out how to wire up the RCA to Phoenix connector I watched this video.



You can buy the actually connectors off a well known auction site. Reason being second hand amps might not come with the connectors. It was more of a bu**er to get the speaker connectors but got them from bpx.co.uk who were super helpful in identifying things. I looked at their web site and lost an hour on connectors and just wanted to build stuff !
 

LittleNipper

Well-known Member
And in use in a pretty impressive rack …

 

jason shep

Well-known Member
Nice find & I see there are also 4 channel models in the range :thumbsup:

I seem to recall, many years ago now though, struggling to find quiet fans for 1U cases, hopefully they are out there now, please let us know if you manage to get hold of some.

Lab.Gruppen E 4:2 Pro Amplifier Review :(
 
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LittleNipper

Well-known Member
@jason shep Where there is a will I always say. I’ll have a good hunt around. How long ago was it that you tried ‘em ?

Did you REW them at all against another amp to determine if they did anything to the sound, or are you a bit like me … yep … sound ok and just get on with it :)

Tar. Paul.
 

jason shep

Well-known Member
Hi Paul,
It was at least 10 years ago now, it wasn’t Lab Gruppen amps but they were 1U & I didn’t go with them as I couldn’t source quiet fans.

Definitely no REW for me, I like to run auto eq & then just enjoy!
 

Paul7777x

Distinguished Member
Definitely a superb price.

When I eventually get round to making my speakers active I’ll be peering intently at these. 👍
 

LittleNipper

Well-known Member
I think I've found the replacement fan for them :-


Less than £13 delivered from a certain web site that should be called Jeff. Just waiting for Noctua's tech support to come back to me, then I will get a pair. However, even without them and watching a few movies these amps don't get too warm. You know, you can put your face on them perfectly well.
 

mossym

Distinguished Member
those fans and their brethern find themselves into a lot of applications as replacement fans, i have a 3d printer which is using some of those to replace the stock fans to get the noise down and no issues
 

LittleNipper

Well-known Member
The replacement fan(s) have turned up. 10 min to swap out. Electrical tools needed - pair of pliers - yep, that simple.

So, I cut the end off the old fan, so I have the correct connector going on to the circuit board. Then use one of the supplied adapters that just communicates through the two wires needed and that's it. Put new fan into place ( it's held by pressure ) and put the case back on.

To connect the two wires they have these little snap connectors (3M Skatchlok). So, you put the wires into the device and then use the pliers to 'lok' the two bits of wire. I've not used these before ( I usually use WAGO connectors ) but they are really neat. You need two, they supply four !

So, now I've get a perfectly quite fan ( 14db I think ). Just running a movie through the amp to heat it up, so the fan turns on. Fingers crossed. I would say the new fan is perhaps .5mm - 1mm wider, which is no bad thing as it just means it aint going to move as the original fan isn't screwed in to anything.
 

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Conrad

Moderator
Where are you getting these amps for £100 from? I looked and couldn’t see anything close to that cheap.
 

LittleNipper

Well-known Member
For now I've PM'ed you as I want a few more. Once I'm satisfied I will be more public.

Pic of them in a Trinnov Rack.... For doubters ;-)
 

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simonb3665

Active Member
Didn't test too well on audio science but he may have had a config issue.
The Lab should be pretty reliable though and can't argue at that price.
Always nice to have a silent noise floor too.
Do you find the NF-A4x10 fan silent? What's it like compared to the Crown?
 

LittleNipper

Well-known Member
@simonb3665 You are quite right, they tested poorly. However, I think they were running at full blast which is never good. They have input trim and I run them about 11-12 O'Clock ( so 50% ) and they sound pretty similar to my Crowns. My crowns sound better than my Denon x3600h ( I think ) and if your using them for Atmos you are not going to notice.

What a tests shows a speaker or amp perform at is one thing, if you can hear the difference is another and if you can get these at this low price well.... You're welcome to go spend £2195 on a Lyngdorf SDA 2400 which provides the same power at 8 ohms. Would you hear the difference on Atmos heights ? My money is on no.

I had some 10 year old Active speakers with built in DAC. Bought a new £500 sound DAC and used the RCA inputs to 'upgrade' the DAC. The DAC went back it degraded the signal as far as my ear go.
 

LittleNipper

Well-known Member
NF-A4x10 Fan.... Is is silent....

Well, no. Infact when it cracks on and if not in a rack, it's worse than the very quite Crown's fans.

I'm going to run them for a bit without FAN as to be honest, I don't think under normal usage it will need them. These amps are designed for install applications where they are on 24/7.

I did get an email back from the manufactures of the fan and there is a way to clock the fans down, so I will look into that and report back.
 

LittleNipper

Well-known Member
Auto On

@Conrad and @jason shep to give you some more details :-

It is possible to set what is deemed a 'noise floor' on these amps. Essentially determines what your idle noise in it from your processor. It will then set a limit 6db above that and until that limit is reached - i.e. When you get channel sound, as opposed to back ground processor or line noise it will turn the channel on ( instant ).

This means when nothing is going on, you've got NO sound from your speakers.

I was driving 4ohm speakers from the amp. I intend to drive 8ohm speakers which are quite sensitive so hopefully my attenuation will be even lower than is is for the MK Sound speakers, so hopefully less distortion which in use. Look, I was listening to the 'The Greatest Showman' Never Enough the vocals coming through this amp were no different to the Crowns or Denon amps.

If you run without the fan, I'm 99% sure over a sitting of 4-6 hours it will be fine. If it isn't they will handle it with normal protection measures.

I'll keep the thread updated with the changes the fan manufacturer says I can do as well as running without a fan again.
 

LittleNipper

Well-known Member
After a little digging around ( and some technical assistance from the FAN manufacturer - Noctua ) the fan actually comes with two adapters. Please, don't beat me up as I don't understand fans....

Default speed is 5,000 rpm

Then the two adapters use one or the other ( indicates to use one per fan ) will reduce the rpm to :-

4,400 rpm ( NA-RC10 )
3,750 rpm ( NA-RC12 )

Which would then reduce the speed. I will do a db test of the FAN ( facing me ) at 1m. I will also see what happens if I daisy chain the leads to see if that also reduces the noise ( and of course the fan speed ).

However, at worst, put the thing in a rack. At the moment, I can hear mine more prominently as it's sat on-top of my cabinet that holds all the other amps.

When I get to my final conclusion I will update the first post with a summary and conclusion so others can then make educated decisions without having to read all my ramblings.
 

LittleNipper

Well-known Member
The FAN reducer really helps. Alas, it's too noisy to actually measure the db of it as it's raining and the in-laws are around talking... Ok, they are also helping cleaning the house a little, so I should not complain.

Because of the rain the noise floor in the room is about 38 db. I will wait until the afternoon and proceed.... But from what I can hear from the racket that's going on in the house, the FAN reducer resolves the problem.

Oddly enough the rain seems to correlate with the first chart I found !
 

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LittleNipper

Well-known Member
Ok. Just watched superman man of steel -14db. Driving centre speaker with this amp for full movie and the fan kicking in. With the arse of the amp pointing at me at 1m 36db. You can’t hear it.
 

LittleNipper

Well-known Member
This is a bump so you can see the updated first item in the thread. I've invited the chap to the forums, that way he would avoid ebay fee's. When I dealt with him he was very curtious and his packaging was spot on, which is unusual for some ebay stuff.
 
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LittleNipper

Well-known Member
Ah this might ( or might not ) make things a little clearer. This amp is a little more intelligent than I thought. I was running one MK Sound MP150 through it and thought it seemed to be getting more power than I thought.... With only one channel used it puts the 400W into 8ohm, 4ohm and 2ohm. My attenuation was at about 12 Oclock. Ignore the fact it also deals with 70V stuff.
 

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LittleNipper

Well-known Member
Well, that's my bed layer and a sub sorted. Got some other amps for LCR.

Bought one more than I needed of the Lab Gruppen's, so I can keep one spare as a 'just in case'.

So, that stack gives me 12 channels at 200W ( all driven ). About £55 a channel. BOOM !

So, I'm working on the theory I will get more benefit spending my funds on a good processor rather than better amps, so Just need to find a discounted Trinnov 16.... ( Already on it - however, hens teeth ).
 

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