Problem with Ampeg Micro VR with 2 AV210 cabs

[fenderhutz]

PLEASE READ THE POSTS BELOW. UPDATED TO REFLECT TECH SUPPORT CONVERSATIONS.

This thread is addressing the issue that happens with distortion and clipping on SPECIFICALLY the Ampeg Micro VR head running two 210AV cabs.

Thanks.

[BassmanPaul]

JimmyM was having trouble with his set up. He had a thread on the problem.

[MuzikMan]

I don't think "crack sound" means the same thing to both of us!

[fenderhutz]

Not a clip or overdrive type of clip, but a crack like when you set a digital signal too hot. Not a pleasant sound.

Oh yeah, and a mod feel free to merge. Please.

[JimmyM]

let me first just say that i still love the micro vr and 210av, and use mine all the time. i honestly think it's one of the best little light-to-medium rigs on the market. but yeah, i'm familiar.

i have measured the cabs, and they both read in the 7.5 ohm area. together they read about 3.7 ohms. i have used the cabs with all my other amps, including my svt, and the cabs work great and put out some pretty serious crank. and the head does none of that clipping when hooked up to my 4 ohm 810 or my two 8 ohm b-15 extension cabs. i can even defeat the preamp in the micro vr with a vt pedal, or run the micro vr's preamp into a power amp, and you can crank that gain and all you get out of it is a sweet grind just like when you crank the gain with only one cab hooked up. and yes, everything is in phase (could smell that question coming ).

but yeah, for some reason, the second the clip light comes on when using the two 210av's, i get that harsh clipping. at first i thought it was a couple of my basses being too hot and putting out too many lows, but it does it with all of them, even the quiet ones, and it never happens with any other configuration. seems to only happen on the low notes E-A. the totally bewildering thing is how well everything works separately. i can't think there's anything really wrong with the head or cabs, yet here you go. love it, but just totally bewildered.

[lowendrv]

JimmyM, I just finished reading the thread you had on this and was wondering did Ampeg get back to you on it. I thought at one point they were going to send another head to A/B.

[billfitzmaurice]

This could be an impedance problem caused by the drivers and sealed cab. Tube amps don't like vented cabs loaded with low Q drivers. By the same token SS amps can be cranky with sealed cabs loaded with high Q drivers, which the AV210 are. The symptoms sound like excess current draw. This chart shows an impedance comparison of these two driver/box combinations. The sealed high Q cab, blue trace, has a lower average impedance, which results in higher current demand. Tubes, no worries. SS? Could be.

[JimmyM]

Originally Posted by lowendrv

JimmyM, I just finished reading the thread you had on this and was wondering did Ampeg get back to you on it. I thought at one point they were going to send another head to A/B.

ya, ampeg's been great with me. got no complaints about their cs. it's just that since everything else works great separately, i really don't know what they can do, unless it's something freaky with the high q speakers as bill describes. but i don't know enough about it to know for sure. sounds logical enough, though.

bill, is this something we can measure ourselves? i thought about pulling out the meter and measuring impedance when hitting a low note as it clips. would that reveal anything?

[fenderhutz]

Good info Bill, thanks for posting.

[fenderhutz]

Called and talked to Tom (?). Now it's just a waiting game. He wanted me to check the ohm on both cabs. Might take a couple days.

[ebradfordrich]

I'm interested in the outcome of this as well. I just picked up a micro VR cab/head and was thinking about adding a second av210.

General question to anyone else following this. What are your thoughts of 1 cab vs. 2 in this setup (clipping issues aside)? I'm just curious. I found another av210 on the cheap but I don't want to buy it if this is a common issue.

[DanNowhere]

I've noticed something when I'm running two cabs. Not so much a crack as a bit of bad distortion, usually playing finger-style. It goes away if I back off the bass and mids a little bit. I usually play with a pick, and it hasn't shown up during any of my gigs or practices as long as I'm picking and not playing fingerstyle.

Tomorrow night I'm taking the two cabs to practice to run a different head through (V4BH) to see if I get anything similar.

[JimmyM]

Originally Posted by ebradfordrich

I'm interested in the outcome of this as well. I just picked up a micro VR cab/head and was thinking about adding a second av210.

General question to anyone else following this. What are your thoughts of 1 cab vs. 2 in this setup (clipping issues aside)? I'm just curious. I found another av210 on the cheap but I don't want to buy it if this is a common issue.

the tone of the two cabs together is fabulous. but to be honest, it's happened with 3 different heads and 3 different cabs for me.

[DanNowhere]

I played the V4BH through the 2 cabs for about three hours off and on last night at practice. Not a crack, pop, distortion, or anything. I even turned on the Ultra-High and Ultra-Low, changed the settings around a bunch. Sounded just fine.

[billfitzmaurice]

Originally Posted by JimmyM

bill, is this something we can measure ourselves?

You'd need one of these:
Dayton Audio WT3 Woofer Tester

[fenderhutz]

Originally Posted by DanNowhere

I played the V4BH through the 2 cabs for about three hours off and on last night at practice. Not a crack, pop, distortion, or anything. I even turned on the Ultra-High and Ultra-Low, changed the settings around a bunch. Sounded just fine.

It only has an issue with the Micro VR head and the 2 210AV cabs. Any other heads with the cabs are fine, any other cabs with the head are fine.

It's really making me a little upset at this point, not because Ampeg support hasn't been helpful, but because I like the way this setup sounds but you can't get a decent volume without clipping the power section of the amp (an early consensus is that it has to do with the high Q of the drivers).

There other issue is that the Ampeg tester I talked to HAD NOT tested the Micro VR with 2 of the 210AV cabs, just 1 210AV and another 15 cab which the issue doesn't happen. I would have thought the setup would have been tested as a group first.

I either get a new head, or a new cab at this point. The Ampeg tech said if I had the ability to return the cab to just return it. I highly doubt if it is a design flaw (which I am kinda falling on the side of now) they would/could do anything to fix it other than bump the wattage of the head and do a trade in program for those that have a warranty on a semi-faulty setup. I know that statement is harsh to a degree but I have an amp I can't use for what I bought it for or sell and lose money now.

On a kinder side, the Micro VR setup with 1 210AV is stellar. Add another 210AV and it's not happy.

[JimmyM]

Originally Posted by billfitzmaurice

You'd need one of these:
Dayton Audio WT3 Woofer Tester

spend money, eh? i'll pass but thx for the info.

[joshwilkesbooth]

This exact same thing happens with my setup. Total bummer.

[fenderhutz]

Originally Posted by joshwilkesbooth

This exact same thing happens with my setup. Total bummer.

Call or email Ampeg/Loud support and in the subject line put "Ampeg Micro VR with 2 210AV cab distortion issue". I am not happy and I will end up selling this setup for a loss. I like the way the thing sounds and in ANY other configuration it works fine.

Loud Tech

1-800-898-3211 or email livesoundsupport@loudtechinc.com

[aborgman]

Ouch...

This is sounding more and more like a design flaw that absolutely should have been caught in pre-release testing.