New to me- Ashdown ABM 500 Problem

[Jim C]

Just bought an Ashdown ABM500 Evo III on Reverb.
I bought this amp knowing the subsonic feature did not work although everything else was supposed to be A-OK. The pots and sliders are a little scratchy but no big deal.

The problem:
* If you engage the mute function and then turn it off, it takes about 2 full minutes before you get any sound; almost like the tube is warming up but that isn't the issue. The VU meter reads signal during this no sound time and turning the tube off doesn't make it work.
* If you remove the instrument cord and then pug it back in, no sound for approx. 2 minutes.
* The same happens if you disconnect the speaker cable when the amp is on (with no signal).

Tone is excellent but the compressor is whacked. It kills volume in a big way even with light compression.

I paid $300 for the amp which came with a new flight case so if the fix is cheap, it might be worth keeping.
Any ideas?

 

[BassmanPaul]

Tech time - sorry Jim but it’s the best way.

 

[Jim C]

Thanks Paul,
I'm going to contact the seller beforehand.
Good thing I'm friends with the owner of a large MI repair shop that is close by!

Do you think this might be caused by a protection circuit timer?

 

[BassmanPaul]

Not being familiar with the amplifier I hesitate to pass a judgement on it. With luck it’ll be a cheap and easy fix. Let us know what the problem was.

 

[Dasgre0g]

What ended up happening?

 

[Jim C]

Just got it back Friday and was going to post!
Resistor in the mute circuit and caps in the power supply needed replacement.
Have been using a 800 Fusion, SVT, SVP-CL pre/power rig, and Fender 800 Pro.
Right now this is my favorite amp; love the clean and blendable tube pre.
The compressor is just OK although I really haven't tried it in a band mix but will on Tuesday.

BTW, if you try one of these amps with the EQ flat, it will have a ton of bottom and seem dull. You may not like it.
I have to pull a fair amount of bottom, slight mid bump and pull a little treble for it to get close-ish to a flat EQ SVT.
This, with the valve drive at about 11:00 is what I really like.

It has that big iron sound with a solid bottom and authority that some micros / other amps don't have.
Very happy with this purchase!

 

[xroads]

BTW, if you try one of these amps with the EQ flat, it will have a ton of bottom and seem dull. You may not like it.
I have to pull a fair amount of bottom, slight mid bump and pull a little treble for it to get close-ish to a flat EQ SVT.
This, with the valve drive at about 11:00 is what I really like.

It has that big iron sound with a solid bottom and authority that some micros / other amps don't have.
Very happy with this purchase!

This is what I like about the ABM500 - it has a great presence in a rock band setting.

Also, I agree with your EQ suggestions, I tend to pull down the lowest bass slider quite a bit though, and leave the bass knob a slightly below
noon. Guess it also depends on the cabs you are using.

 

[Dasgre0g]

Just got it back Friday and was going to post!
Resistor in the mute circuit and caps in the power supply needed replacement.
Have been using a 800 Fusion, SVT, SVP-CL pre/power rig, and Fender 800 Pro.
Right now this is my favorite amp; love the clean and blendable tube pre.
The compressor is just OK although I really haven't tried it in a band mix but will on Tuesday.

BTW, if you try one of these amps with the EQ flat, it will have a ton of bottom and seem dull. You may not like it.
I have to pull a fair amount of bottom, slight mid bump and pull a little treble for it to get close-ish to a flat EQ SVT.
This, with the valve drive at about 11:00 is what I really like.

It has that big iron sound with a solid bottom and authority that some micros / other amps don't have.
Very happy with this purchase!

had a similar issue with my abm 900. Just needed a cap replacement. Got it back in 30 minutes. I was terrified!