EA Micro 550 into Schroeder 1212 BMF - headroom issue

mrpackerguy · #1 08-30-2010, 07:21 AM

At most gigs. I'm playing a NS WAV4 EUB for 1-2 hours, then BG for 4 hours. I had high hopes for the new EA Micro 550 I just received, being 2 channels, high input impediance for the piezo pickup on the EUB and portable to be able to be used for both the EUB and BG portions of gigs.

However, I'm not getting near the expected volume with the Micro going into my Schroeder 1212BMF 4 ohm cab. With both gain and master maxed, I've got no headroom and I'm questioning whether I even have enough stage volume on the BG portion of the gig even with PA support. Tone-wise, it's clean and useable. The manual that came with the Micro says to adjust the gain until the yellow LED light blinks intermittently. I can't get the yeallow LED light to come on with either instrument. On the BG side, I'm using an active Stingray 4. Even using my ultra-hot Lakland 55-02, can't get the LED to barely come on at all.

I've got a 4 ohm EA Wizzy 10 coming this week. Maybe I'll find that the Micro with the Wizzy will be enough, but I was really hoping for a one solution head. Running a K&K Pure preamp between the cab and the instruments has helped some, but the headroom issue remains.

I love everything about the EA Micro except the headroom issue. Anyone else experiencing this or have any thoughts?

KJung · #2 08-30-2010, 07:49 AM

Doesn't that head have a input pad as one of the little 'top of the amp switches'? If so, make sure that isn't engaged.

The 212BMF is a VERY loud per watt (SPL) cab. Even though the EA550 is at the low end of volume output compared to other similarly rated micro's, something is strange, especially since the MM has a relatively hot output.

If it is not a pad switch issue, you might need to send it back and have the gain stage adjusted. EA is very good about doing this for customers.

Edit: Just checked the manual on the EA site... yes, there are trim controls for each channel on the top of the amp. That is most of your issue. Adjust once channel for your EB and one for your DB, and you should be good to go.

KJung · #3 08-30-2010, 07:57 AM

One other comment... the BMF cabs get their high SPL partially due to the low end being quite rolled off. If you are trying to make a BMF cab sound like an Acme by cranking the bass, then the high SPL becomes VERY low SPL, since the amp is working very hard to pump out the lows below the -3db and probably -10db range of the cab.

As long as you like that tight, punchy voicing, and don't need to shake the ashtrays in the back of the room, with the trim set correctly, that rig should sound very good.

mrpackerguy · #4 08-30-2010, 08:10 AM

Quote:

Originally Posted by KJung

One other comment... the BMF cabs get their high SPL partially due to the low end being quite rolled off. If you are trying to make a BMF cab sound like an Acme by cranking the bass, then the high SPL becomes VERY low SPL, since the amp is working very hard to pump out the lows below the -3db and probably -10db range of the cab.

As long as you like that tight, punchy voicing, and don't need to shake the ashtrays in the back of the room, with the trim set correctly, that rig should sound very good.

Yea, I've done the voume pot trims (which are actually written wrong in the manual as counter-clockwise produces more volume) but yea, I was running up the lows, not to get them to sounding like Acme's but to try and mask the hi's. I'll try backing off the lows tonight and see if I can get more headroom. Also, sending it back to get any internal trim pots adjusted which can't be entirely adjusted from the available trim pot adjustments is a good idea too.

KJung · #5 08-30-2010, 08:33 AM

Quote:

Originally Posted by mrpackerguy

Yea, I've done the voume pot trims (which are actually written wrong in the manual as counter-clockwise produces more volume) but yea, I was running up the lows, not to get them to sounding like Acme's but to try and mask the hi's. I'll try backing off the lows tonight and see if I can get more headroom. Also, sending it back to get any internal trim pots adjusted which can't be entirely adjusted from the available trim pot adjustments is a good idea too.

Cool. Good luck with it!

Smallequestrian · #6 08-30-2010, 08:44 AM

That's strange, I did a lot of gigs with that cab and a Little Mark (of similar wattage) and with the gain and master at 12 o'clock it got ridiculously loud. Something doesn't sound right there...try to borrow another head from somewhere or take the cab into a GC and hook it up to another amp. It should be really loud.

mrpackerguy · #7 08-30-2010, 09:05 AM

Quote:

Originally Posted by Smallequestrian

That's strange, I did a lot of gigs with that cab and a Little Mark (of similar wattage) and with the gain and master at 12 o'clock it got ridiculously loud. Something doesn't sound right there...try to borrow another head from somewhere or take the cab into a GC and hook it up to another amp. It should be really loud.

Actually, that what I was hoping for was volume/headroom approaching the LMII. I don't understand the science or even the basics about imput impedance, but from what I was able to gather from the DB forum, the higher input impedances like the Micro work well for piezo pups as found on EUB basses like the WAV4.

KJung · #8 08-30-2010, 09:23 AM

Quote:

Originally Posted by mrpackerguy

Actually, that what I was hoping for was volume/headroom approaching the LMII. I don't understand the science or even the basics about imput impedance, but from what I was able to gather from the DB forum, the higher input impedances like the Micro work well for piezo pups as found on EUB basses like the WAV4.

That EA amp is not going to put out the volume of the LMII.

A high input impedance will make an unbuffered piezo pickup sound less harsh and clacky, which is a positive. However, once you buffer the piezo with an external preamp, the input impedance of the amp becomes a moot point, and buffering with a preamp voiced for a piezo almost always sounds better (IMO) than a relatively high impedance input on an amp head.

Hopefully, that head will work for you. If it doesn't, and you want to use that 'raw' piezo pickup, Markbass now has a special dual channel preamp module for the Momark with a high input impedance (and I think combo input jacks for mic's) that looks pretty cool.

Edit: That preamp module has one combo jack with phantom power and one regular input. However, input impedance is not listed in the specs, so that might not be an option. I assume the input impedance was raised, since it says the module is designed for DB, but not sure.

mrpackerguy · #9 08-30-2010, 03:48 PM

Not all power cords are created equal.

Pulling out all stops, I un-twist-tied the power cord that came with the Micro. I compared the markings. EA = 250v. Power cord I was using (from my Mpulse or B1500) = 125v. Guess what? That's what made the difference.

I would say close to twice the volume, but still no headroom. And, I am able to get the yellow LED to light up now. Yes, it did help to back off the low on the Micro and boost the lows on the bass.

OK, close to useable now. Waiting for the EA Wizzy 10 to mate with it to see if this will work as an EUB set up.