Hello all,

I have an Ashdown MAG 300 head that has a very boring tone. I would like to re-tune the EQ to match the frequencies that an Ampeg SVT has. The amp will not suddenly sound like an SVT I know, but I always feel the controls are better placed in an SVT in terms of the tonal spectrum.

I've found a schem for my amp here at the bottom of this page;

http://music-electronics-forum.com/t28046/#post307779

On the Ashdown, there are five EQ controls. They are, and their frequencies are;

Bass - 100 Hz
Mid - 650 Hz
Treble - 7 kHz

Lo Mid - 340 Hz
Hi Mid - 1.6 kHz

This doesn't seem like an ideal spread to my ears. I always feel that Ampeg gear has a sweeter mids response.

Ampeg frequencies are;

Bass - 40 Hz
Midrange (switchable at) 220 Hz, 450 Hz, 800 Hz, 1.6 Hz and 3 kHz

Treble is at 4 kHz

Ideally I would have the Ashdown 'retuned' so that the bass control was at 40 Hz, the mid control at 800 Hz 'lo mids' at 300 Hz, the 'hi mids' at 1.2 kHz or so and the treble at 4 kHz.

Is this possible just from substituting the caps and resistors affiliated with each control on the schematic?

Thanks in advance,
Kobaia

Hello all,

I live in Edinburgh, Scotland and I'm 24. I've played guitar since I was ~13 or so. I've always had SS amps of various types. At the moment I have a vintage HH VS Musician 212 combo at my parents' house which I've done some work on.

When looking for a smaller amp, I chanced upon a Vox Pathfinder 15R in a pawnbrokers. Having liberated it, I've enjoyed the tones from it ever since. I've done the common LED mod, though I'm not 100% sold on it.

What I would really like to do is mod the tonestack. I would like to make the amp overall less bassy, and more tight sounding. I would also like to maybe reduce the brittle high treble content a smidge. I understand this can be done through the tonestack. I found a thread on here regarding the Pathfinder 10, but it seems that the circuits don't directly translate.

Using the commonly found schematic, I presume that VR3 and VR4 control bass and treble. However these are not near each other, topologically, which makes me wonder how this circuit works. Can anybody shed any light on this area?

It looks like C12, C13, C14 comprise something that looks, to my untrained eyes, like the Vox diagram in the Duncan tonestack calculator. However the bass control is located near C20, if I'm reading the circuit correctly.

Any help would be appreciated. I realise I cannot expect anything too great here, but I feel the tonestack is slightly less than optimal in the 15R, especially given that it is a 2-band EQ. I feel that the bass has become 'flubby' since I removed the LEDs.