Ampeg Micro VR issues poll with new video

[Thijs V]

is about ac and has nothing to do with the power amp

 

[Passinwind]

@Passinwind c 'mon man relax.
It ain't no rocketscience it is normal info on their site. Are you trying to proof my wrong or what?

No worries, I'll contact Ampeg directly.

 

[Thijs V]

I had no worries ;-)

 

[Thijs V]

Fair enough. But how do we know the PF350 doesn't have mosfets? We know the Micro VR is class AB and the PF350 is class D, but does that mean class D can't have mosfets?

Seriously asking this since I don't know. Not trying to be dicky or anything.

We are talking only the poweramps.
And then there are a few possibilities.
Tubes, ss, mosfets or class D. (there is more but this is most common)
There are also preamps with mosfets, but this is not what we are talking.
You can have Pre Mosfet class d poweramp.
Or tube pre and tube power.
Or tube pre and ss or class d power.
etc, etc.
The pf350 is ss pre and class d power.
The micro vr is ss and mosfet power.
The pro 7 is tube pre, class d power.
SVT CL SVT II (pro) are tube pre and tube power.
And so on, there are a lot of different combi's but let's stick to this for now.
Switched power supplies are about feeding the amp and not about output power.
They replace the older transformers and weight a lot less and stay much cooler but are difficult to design.
As you maybe know a tube amp has two trafo's (output and power)
So switched p supplie has not much to do with sound (theoretically)
Back on topic,
As seen before the micro vr has a mosfet poweramp and the pf 350 a class D.
Mosfets behave a bit like tubes (harmonics) that is why the micro vr sound en also feels different then the PF 350.
Class D is good for low frequencies (bas)but but is rather terrible for higher freq's
That is why you don't find class D for guitar but only in bass amps and subwoofers for hifi.
I think that the combi found in the Micro suits me best, apart from the classic tube amps.
So the terms a or ab are not for class d
Class d is class d

A technician can give some more details (or nuances) but i try to keep it as basic as possible.

 

[Passinwind]

We are talking only the poweramps.
And then there are a few possibilities.
Tubes, ss, mosfets or class D. (there is more but this is most common)
There are also preamps with mosfets, but this is not what we are talking.
You can have Pre Mosfet class d poweramp.

Or a MOSFET Class D power amp, which is very common, since all ICEPower modules used in bass amps (and most if not all others) are like this. One term does not preclude the other one.

 

[Thijs V]

You are correct

 

[RoadRanger]

Oy vey yous guys can be funny . I bought the Micro-VR specifically because I like the overdriven sound of linear MOSFET amps - I own three of the older Tube Works amps. IMO they sound very "tube-like". I've since been told that the PF-350 sounds identical even though it has a class-D power amp. I've been unable to determine if those claiming that have ever run the Micro-VR with the limiter off and gain and volume dimed? I've only done that with a 16 ohm load, a 4 or 8 ohm load would be incredibly loud . In truth a situation where you can run the amp WFO would be rare to none. I do rehearse at one studio with a Tube Works 100w combo that I've swapped a 16 ohm driver into so it's not much more that 25w, sounds very B15-ish !

 

[JimmyM]

I've cranked the knobs very hard. Of course the PF350 has more clean headroom before breakup, but I still didn't notice much of a difference at all other than that. However, 95% of the time I run clean and the rest I run with the preamp just pushing a little grind, so maybe you're right that the difference is in the full-on crank. To me it sounds like poopycaca to do that, though, so I get my extreme from pedals and generally run the amp clean.

 

[pgk]

the micro-vr has been my main gigging amp for the last 3 years.

single (ampeg BT15) or dual (Kustom) 15" cabs. it has been gigged Hard and has been an absolute tank in every regard. the only pain in the ASS issue for me are those godawful plastic jacks for the input and speaker connection. those things ought to be illegal. anyway....

master wide open, always
volume between noon to 2:00, always
bass 3, mids 8:00-11:00, treble 9:00-noon
in other words, it is set as loud and clean and fat as i can get it. a tremendous head

 

[Nimu]

after having fun with my micro vr and one 210av cab for years i bought another one and guess what - i have ugly clippings. i can get rid of them when i decrease the volume but then i have a smaller maximum volume than using just one cab.

i asked ampeg support about the issue and got the answer that they won´t repair it for free as the garantiee period is over. in my opinion this is embarassing! i mean ampeg can not expect customers to buy the amp with two cabs just to find out if there is a (design) problem.

anyway, my idea is to switch to the pf350 as i like the ampeg tone and read that it should sound very similar to the micro vr. does anyone know if the pf350 has problems with two 210av cabs?

 

[dls59]

I've run the heck out of my 350 and two 210AV cabs. No issues whatsoever.

 

[Thwack]

I have been running a PF-350 through 2 210AV's for a few years now at small to medium gigs and have only recently started having cut-out issues. I've tried the head through a SVT classic 410 and more recently a pair of PF-115HE and always the same result. I'm playing a Jack Casady which I know has a fairly hot signal for a passive bass but if I roll the volume or gain much past 1 o'clock and dig in hard it cuts out bad. Don't know what to do with it at this point.

 

[Thijs V]

I've run the heck out of my 350 and two 210AV cabs. No issues whatsoever.

No,because this thread is about the MicroVR and not any other amp.
Does anyone know of a cause or solution yet?

 

[JimmyM]

No,because this thread is about the MicroVR and not any other amp.
Does anyone know of a cause or solution yet?

I've played newer Micro VR double stacks that didn't have this problem, and mine cleared up on its own within a few months. I'm guessing maybe as the speakers broke in and loosened up they dealt with it better.

 

[pgk]

could very well be. that little head is such a beast, even at 250 @ 4 ohms, that the speakers in those tiny 2-10 cabs may be crying for mercy. into a Kustom 2-15 cab with a pair of JBL's i can make even them wince in protest if i'm not careful. a Tremendous little head

 

[T-fonk]

Have a brand new stack, now with two new svt210av. Lucky for me, I'm not able to reproduce these cracks/pops, not even with the exact setting from the first poster. I've owned three big SVT-300 stacks, but this little stack's really impressing! I like the sound, it reminds me of the big ones, but with a faster punch. Great cabs, they seem to blend with the rest of the band, in a nice way, not too bottom heavy.

 

[TobiS]

I bought a Micro VR with ONE SVT210AV back in 2011 and I really like it.
Therefore I decided now to buy another SVT210AV to expand this little stack.
BUT – today my new SVT210AV was delivered and I’m noticing the same strong clipping-problems other people mentioned in this thread.
I contacted Ampeg, hoping that they can support me with this...

 

[TobiS]

Just want to give you a short notice about what's happened with my amp...
Ampeg directed me to their distribution partner in Germany, since I live there.

They asked me to send the amp to them - today I received it back.
They fixed the issue for free and now my amp sounds incredible good (as before) - but also with 2 x STV210AV cabinets.
Great. Thanks to Ampeg and to Mega Audio in Germany for this outstanding good support!

 

[sloppy_phil]

Just want to give you a short notice about what's happened with my amp...
Ampeg directed me to their distribution partner in Germany, since I live there.

They asked me to send the amp to them - today I received it back.
They fixed the issue for free and now my amp sounds incredible good (as before) - but also with 2 x STV210AV cabinets.
Great. Thanks to Ampeg and to Mega Audio in Germany for this outstanding good support!

Glad it worked out for you! Pretty classy of Ampeg to take care of it on their dime, even though it's pretty much the right thing to do. Maybe I'm just jaded, but in general I don't expect that kind of help from big comapnies...

 

[RoadRanger]

Argh - got Micro-VR forked at a big gig yesterday. There's a yearly benefit here that I played last year with the Micro-VR into a 4 ohm Kustom 8x10 no prob. I hadn't used the head since then and this year went with one of my 4 ohm GK 212MBE cabs. Got the dreaded "sounds like carp" distortion . I have to engage the limiter and that got me through - but not the tone I was looking for . This is the only gig I can actually open up the head at - outdoors ~1000 cap park. Shoulda just used my Aguilar TH350, awesome amp that does an Ampegish overdriven tone at any volume .

I guess I'll confine the Micro-VR to 8 ohm duty. Problem is I don"t have an 8 ohm cab rated at ~400 watts and I really don't like to overdrive an amp into a cab rated at less that 2x the amp - I could wire my two 4 ohm 212MBE's in series I guess. BTW this is not an early one, I did have a "peeler" that I traded away and then bought a new Micro-VR.

So, how are other folks faring with the Micro-VR into 4 ohms?