Lab.Gruppen E 4:2 Pro Amplifier Review

[tomtoo]

Thats a ELA amp. Nobody that is not insane would use it for home-hifi. Why should you pay for 70(100)V ELA option? You would not even use it for a typical PA application.

 

[jhaider]

The 7 Series appears to be designed solely with the companion Crown amp in mind.

M2+Crown use more common XLR and Speakon connectors.

Many M2 installations, including their designer’s personal pair, use Crown DCI amps.

While balanced XLR-type connections are becoming much more common in hi-fi, one really has to go out of one's 'audiophile/hi-fi' way to interface normal hi-fi gear with these sorts of 'installed' amps, like the LG.

Nonsense. Making an XLR cable requires purchasing an end and soldering wires into cups or crimping pins. Wiring one of these requires only a screwdriver. Any literate person with minimal hand eye coordination can do it. If for some reason one buys XLR cables instead of making the proper length, add scissors.

My general point is simply that dismissing an amp for the connector style is ignorant and stupid. Especially when the connector is actually more user friendly than the standard one.

 

[anmpr1]

Nonsense. Making an XLR cable... My general point is simply that dismissing an amp for the connector style is ignorant and stupid. Especially when the connector is actually more user friendly than the standard one.

Most hi-fi types are not going to make their own interconnects. You know that. You evidently write for a hi-fi Webzine? So you must know that. And if you have to make your own interconnect, how is that 'more user friendly' than something off the shelf or already in your drawer?

"Ignorant and stupid"? Is that the journalism style at your 'zine? I kind of thought that sort of off the cuff dismissive prose went away with Harry Pearson. However it is, how many hi-fi folks do you know using gear that will natively interface with Phoenix connectors? Would you tell them they are stupid and ignorant if they want to use RCA interconnects, or Neutrik XLRs, because that's what's on their other gear? In fact, I'd say it is pretty reasonable for most hi-fi folks to look elsewhere than this LG if for no other reason than the conectors (although there are other reasons in addition to that).

PS: Isn't your place the place David Rich sometimes contributes? If you see Dave, ask him to get more involved if he can. He was always first rate.

 

[jhaider]

Most hi-fi types are not going to make their own interconnects. You know that.

I am aware of an audio cable industry, yes. This place is supposed to be for people several grades smarter than the cable swappers.

And if you have to make your own interconnect, how is that 'more user friendly' than something off the shelf or already in your drawer?

Because it will be the length you actually want, instead of limiting gear placement or leaving unsightly excess.

"Ignorant and stupid"? Is that the journalism style at your 'zine?

My opinions are mine alone. I stand by them, including the above characterization.

However it is, how many hi-fi folks do you know using gear that will natively interface with Phoenix connectors?

Plenty. Many of us (self include) were first exposed to them by our use of miniDSP products: 2x4 balanced, 4x10/10x10, DDRC-88, etc.

Would you tell them they are stupid and ignorant if they want to use RCA interconnects, or Neutrik XLRs, because that's what's on their other gear?

Strawmen are also ignorant and stupid.

What I wrote is that it is ignorant and stupid to dismiss an amp, processor, as “not Hifi” because of the input and output connectors used. That is what was done earlier, and is vastly different from someone saying “I don’t want to deal with that.”

 

[Rja4000]

Maybe airports and bus stations get a discount?

It's not even relevant.
Think of this as just a detail in the contract for wiring the whole building, provide all loudspeakers, cabinets, control room, ...
All this is probably contracted by the Architects' office.
This is just a drop in the sea.

 

[MerlinGS]

Think of this as just a detail in the contract for wiring the whole building, provide all loudspeakers, cabinets, control room, ...All this is probably contracted by the Architects' office. This is just a drop in the sea.

In these types of contracts, reliability is a huge consideration. The price differential is small in the context of most of these jobs, but the peace of mind is not.

 

[Bsinger]

The speaker connectors are

As for I/O, Phoenix connectors are much better than XLR IMO because they only require a screwdriver and optionally a ferrule crimper to use. No soldering or expensive crimp tooling (Neutrik HA ends) requires.

Very well said. The speaker/output connections are far superior to binding posts on consumer amps and even better than speakons, at least in the context of an installed product. They take 10AWG wire with ease (unsure on 8AWG, probably fine) and the screw provides good force on a sandwiching mechanism providing strong clamping power and quite a bit of surface area, more than screws on a banana. They are large easy to attach, have a nice tactile click-in, are low profile, will not come out but easily removed and if you want to switch over to another connection you simply remove the screw. No cutting, no time consuming

The Phoenix inputs are also very easy and I have never had a problem with them but due to the smaller size and wire gauge, they are a little awkward. They feel of XLRs are better. This is largely eliminated by getting the connectors with the molded strain relief. The choice of screws used on the connectors can be issue too, not a fan of flat heads used on many of the connectors.

It also reduces the ability to impress others with your connectors or impart some perception that your connectors are improving sound quality. Pretty tough to drool over green plastic

 

[anmpr1]

What I wrote is that it is ignorant and stupid to dismiss an amp, processor, as “not Hifi” because of the input and output connectors used.”

I don't think anyone here is dismissing this amplifier 'because' of the interface. I didn't read that. What was said several times was that it is not intended as a consumer amplifier, and the terminals attest to that. If it is being 'dismissed' as a viable option it is for other reasons than the terminals.

Personally (and like you it is just my opinion) unless there was some overriding and compelling reason to choose a professional installation oriented amplifier with non-standard interfaces (i.e. non-standard in consumer space) then it is time to look elsewhere. With this LG I see no compelling reason for a consumer to want it. Once that determination is made, I wouldn't characterize that decision as either stupid or ignorant, although I guess that is not what you are saying.

For sake of agreement, and to end on a positive note as friends, I would entirely concur with you that if, say, there was an amplifier selling for half the price of an AHB2 with twice its power along with similar specs, but only offered with Phoenix connectors, then that would be an argument to make one's own cables. You'd want to use something like that. But since that isn't the case, and since cables are cheap and available in pretty much any length (even with custom terminations if you want to pay x-tra) I don't think that sort of DIY construction project is going to take off in any meaningful way.

 

[KSTR]

This is like buying a $130 EREM 670EP swiss-made ESD-safe precision SMD tip cutter for trimming your nose hair ;-)
It sure is up to that task as well, but....

 

[tomtoo]

This is NOT a home-hifi amp! If you like to buy a tractor and than like to discuss how good it is to be on a racetrak with it, ok do it.

 

[Bsinger]

If you want an amp that is reliable, you can pick up fo $100 per channel, doesn't heat up your room, has flexible wattage distribution, gains adjustments, easily fits in a rack and does not depreciate when you want to sell and move on, then a used one of these works well, particularly when you what a full dolby atmos/auro set up. And you don't need a new electrical sub panel

If you are a two channel guy, not so much

 

[Bsinger]

Check out this home theater incorporating a few of these amps

https://procella.audio/private-home-theater-in-the-netherlands/
Lab Gruppen Home Theater

I suspect it sounds pretty good

 

[Tips]

I will ask amir@. I have a 1200 IPD.

Many thanks Pierre. Let's hope Amir nods on this one !

 

[Vladimir Filevski]

A) I would think that in its intended installation (airport, mall, etc) the primary concern would be whether it will drive installed speakers ...
If it can drive the PA speakers over a long distance connection then the power would be adequate. No?

For such important and crowded places (airports, bus or train stations, etc) of paramount importance is that all public announcements must be heard loud and clear. That means installed loudspeakers must be in such a number and position, and with such sensitivity, directivity, frequency response and input wattage, to fulfill projected and calculated requirements for SPL and low distortion. Of course, installed amplifiers must deliver the calculated wattage, otherwise the required SPL will not be met. And if the required SPL is not delivered, the engineer who specified concrete 200 watt amp which in reality outputs only 101 watt, will be fired and sued (in that order).

B) I would think that the fact the amp will not readily interface with any standard hi-fi gear disqualifies anyone anywhere from seriously considering this for their living room stereo. The back of the unit is not like certain Crown amps some people use in their home hi-fi. Some of those even have RCA connectors. Maybe in Europe it's different.

As someone pointed out earlier, those Phoenix connectors are super-easy to use: just cut some Belden cable to the required length and use a regular screwdriver to secure it. No expensive deep cryogenically treated pure monocrystal copper core, gold plated Teflon insulated RCA connectors or speaker 5-way binding posts. Actually, those "Phoenix" connectors are known as "Euroblock" connectors here in Europe, and are very common. Any audiophile here I am aware of know how to connect an audio gear with Euroblock connectors. And every other non-technically oriented audio consumer know at least one technically adept person to help him. Euroblock connectors are inexpensive, secure and easy to use.

 

[anmpr1]

. Any audiophile here I am aware of know how to connect an audio gear with Euroblock connectors. And every other non-technically oriented audio consumer know at least one technically adept person to help him. Euroblock connectors are inexpensive, secure and easy to use.

I was writing parochially, living in the US as I do. So my comment was limited to that extent. Euroblock has advantages. You can put a lot of balanced connections in to a relatively small form factor. They appear to be snug. I don't know how RCA connections became the norm here. They are horrible connectors, but ubiquitous. I am happy to see more gear using Cannon-type XLR plugs. XLR appears to be more readily accepted in home hi-fi in the US. So that form factor is bridging the gap between pro and consumer.

Probably the most common pro amp (I'm guessing) used in American homes by hi-fi consumers who buy 'off the shelf' are the value-oriented Crown XLS series (they are cheap, powerful, and readily available from any guitar store). They offer a variety of inputs that will interface with a variety of preamplification--XLR, 1/4", and RCA. Also ergonomic Speakon connectors (plus traditional binding posts). But no Euroblock. Other more directed Crown amplifiers offer them. However, I suspect that those models are not often considered by home hi-fi users looking to upgrade their living stereo system.

 

[Vladimir Filevski]

Probably the most common pro amp (I'm guessing) used in American homes by hi-fi consumers who buy 'off the shelf' are the value-oriented Crown XLS series (they are cheap, powerful, and readily available from any guitar store).

The same here: XLS series, but also XTi (built-in DSP equalizer) and XLi (bare bone).
Second-hand amplifiers with Euroblock connectors are popular choice here, because of the lower price than comparable quality/wattage pro amps with conventional pro connectors.

 

[HighImpactAV]

I have installed Lab Gruppen E Series amps in 4 venues and own several myself. I'm also an authorized Lab Gruppen dealer. First, Lab Gruppen rates the power for both the D and E Series use a sine burst signal used to represent actual music content. It used to be noted on their website or literature, but I can't find it right now. The E12:2 was independently tested to meet the specs with a sine burst signal. I don't agree with Lab Gruppen's decision to rate these models this way.

This is a current sharing amplifier (all channels share the current) and allows one to load it asymmetrically. This is of great value in a mixed speaker environment and also why the Low-Z or 70v options exist. "The E Series is designed with inherently bridged outputs for a high voltage swing, with full headroom accessed in the 70 V mode. So, in some ways the amplifier is a 4 channel amplifier with permanently bridged outputs which turns it into a 2 channel amplifier. This design also accommodates asymmetric loading, wherein only one channel can be connected and draw all power from the power supply. Alternatively, one channel can be connected and configured as a “high power” channel while another is connected and configured as a “low power” channel. For example, a 4 ohm loudspeaker could draw all the power available from the power supply in one channel when it is the only loudspeaker connected to the amplifier. If another channel is connected, any power used by this second “low power” channel will limit the “high power” channel from using all available power."

I like to use one channel for mains and one for surrounds with a different impedance for each channel. Since any channel can get maximum voltage or current, one can use a load balancing method of connection on the E 10:4. For a pair of E 10:4 amps I would put the left channel on one amp and the right channel on the other amp. This way the amp basically acts as a monoblock with full power for those channels when listening to stereo content. For surround channels, I balance them so as a sound pans around the room, the minimum number of channels is in use. There are many times when all channels will be used, but I still like to balance the load.

The 70v option provides 8 dB more output (on the E 4:2) and really should be used for all home theater applications regardless of impedance. This difference is clearly stated in the specs. The higher output voltage is of benefit and provides more headroom. When in 70v mode, the fans rarely run so the amp is completely quiet. The fans don't run all the time and the manual agrees, "The E Series amplifiers have very low idle power draw and they are very efficient. However, to reduce the risk of engaging thermal protection, the amplifier has been designed with a forced-air cooling system (air flow from front-to-rear) that activates as needed. "

The rated SNR of >112 dBA is probably correct. However, this is with the amplifier properly setup and using high input voltage. From the manual, "On all E Series amplifiers, the input stage has a relatively high sensitivity of 4 dBu (1.23 Vrms) for full power. However, the input can handle signals up to 17.2 dBu without clipping the input signal path. The amplifier applies low-distortion limiting if the input signal exceeds what is required to deliver full power. If compression isn’t desired, use the input attenuator to trim the sensitivity. E Series amplifiers easily achieve a high SPL when driven with sources capable of 10 or 20 dBu output, such as professional mixing consoles or DSP units. " I use +20 dBu input in the amp and then use the input attenuator to adjust to the proper level. This greatly increases the SNR and makes for a no output hiss even with speakers around 100 dB sensitivity.

What input voltage was used for testing? The input attenuator was all the way turned up and it looks like 5Vrms was input. This is why the limiter kicked in if this indeed is how the test was ran.

The benefit of the E series amps is that they have an operating voltage range of 70-26VAC (increasing reliability), are almost completely silent, automatically turn on/off for lower power draw, can accept high input voltage for maximum SNR, have four channels in a 1U format, are super easy to connect, share current so a single channel can output the maximum power, have balanced input, are fully bridged to eliminate bus pumping, provide all kinds of protection (thermal, current, voltage, DC), and have a flat frequency response down to 2 Hz. They also have a great warranty of 10 years! The E10:4 will outperform almost any receiver's internal amplification.

By the way, the E 4:2 is no longer available.

 

[Bsinger]

I have installed Lab Gruppen E Series amps in 4 venues and own several myself....
By the way, the E 4:2 is no longer available.

I think you are saying it makes a pretty damn good amp in a multi channel home theater set up, yes? Would you expect the working used amps out there to be reliable?

My experience has been good in my home theater that includes five 4:2 and one 5:4 all on just one dedicated 20 amp circuit powering 11 speakers crossed at 100 hrz (a separate circuit for subs). I hit reference levels with no heat problems, rack space issues, clipping, limiting, blown circuits, etc. I think I could add even more channels.

This is not to say I wouldn't prefer Hypex, Purifi, Pascal... I do wonder if the SQ (SNR, etc.) differences would be noticeable?? Excluding the placebo effect, I am guessing that would be a no for most movies, a probably not for 5.1 music and a tiny bit for 2 channel. Any thoughts?

 

[amirm]

What input voltage was used for testing? The input attenuator was all the way turned up and it looks like 5Vrms was input. This is why the limiter kicked in if this indeed is how the test was ran.

No, that is just the vertical scale on the graph. For the dashboard input was about 0.2 volts which produces 5 watts. That was for the dynamic range on the left. For the one on the right, I kept increasing the input voltage until I limited.

Gain differences usually account for 2 to 3 dB. The reason they report much larger numbers for SNR is likely because they use a-weighting which I do not. That filters out a lot of noise and hum resulting in better numbers.

 

[jhaider]

AActually, those "Phoenix" connectors are known as "Euroblock" connectors here in Europe, and are very common.

Interesting! Here I've always heard those called "Phoenix terminals [or connectors]." "Euroblock terminal" I've usually seen refer to this style of insulated barrier strip:

If it is being 'dismissed' as a viable option it is for other reasons than the terminals.

How would you interpret this sentence?

"I would think that the fact the amp will not readily interface with any standard hi-fi gear disqualifies anyone anywhere from seriously considering this for their living room stereo."

That's not a comment on this Lab Gruppen amp. It's a blanket, and factually incorrect, statement referring to all amplifiers with similar inputs, including Crown DCI/JBL Synthesis and any number of others. FWIW, several amps I've personally purchased in the last half decade - Crown DCI Network, QSC SPA4100, Lab Gruppen LUCIA 240/2M - use Phoenix connectors for signal inputs, and either Phoenix connectors or fixed barrier strips for speaker outputs. Crown DCI Network and QSC SPA amps are absolutely used in the living room "stereo," albeit to drive 4 subwoofers and 4 height speakers, respectively.

That said, when I sent the BSS BLU-BIB and BLU-BOB to Amir for testing, I included XLR pigtails for inputs and outputs for his convenience. For a personal system that is not necessary, though it should not hurt anything either.