Vox ac15tb > ok with a 16ohm spkr?

[Chuck H]

Here's a gut shot of a late 90's AC15TB. Clearly only two secondary leads. As Pete noted, it could be that the 16 ohm lead is cut off under the bell covers. Maybe it's just a manufacturers asset for specific amp/cabinet options. At any rate it doesn't seem to be an easily accessible option for the amp owner.

[Sea Chief]

Here is a photo, and it appears there is only the 2 secondary wires you mentioned, so no other tap than the one in use.
As you say, if he is not pushing the volume, it should be fine to use the 16 ohm speaker.

Thats some good detective work g1- cheers/ yes indeed I took the amp out & there were no extra wires not even visible under cover. So that schematic is a bit misleading then.

Ok so as to resale value, I guess putting in the 16ohm instead will detract from it's value?

[Sea Chief]

Chuck H useful guts shot- appreciated Chuck/ not seen that one either.. yi guys sure know how to sniff things out! I think you were bloodhounds in a past life.

I was considering the idea of modifying it so that pic is very useful: there's a "tonemanmod" involving adding a choke + possibly another few minor additions. Here you see they can command a very good price: https://reverb.com/item/146465-90s-v...agnetics-ac-15

[Jon Snell]

So that schematic is a bit misleading then.

That is because it is a Chinesium Vox, made by Korg.
It is what it is but as I said in my first post, no components will be harmed using a 16 Ohm speaker at reasonable volume levels.

[Sea Chief]

That is because it is a Chinesium Vox, made by Korg.
It is what it is but as I said in my first post, no components will be harmed using a 16 Ohm speaker at reasonable volume levels.

No its made by marshall in UK, the schematic is correct for my amp. You're correct that the ac30 tbx etc were made by korg, but in UK 90's. Its the much later reissues ..CC1 types that are chinesium.

[pdf64]

That is because it is a Chinesium Vox, made by Korg.
It is what it is but as I said in my first post, no components will be harmed using a 16 Ohm speaker at reasonable volume levels.

Here’s some info regarding this model http://www.voxshowroom.com/uk/amp/15tbx_hood.html
ie Marshall got the contract to design and build this era of Vox valve amps.

[vintagekiki]

Which model AC15

http://www.voxshowroom.com/uk/amp/bedrock_ac15tb.html
OR
http://www.voxshowroom.com/uk/amp/ac15tbx.html
OR
http://www.voxshowroom.com/uk/amp/ac15cc1.html

[Jon Snell]

I stand corrected. It is the solid state newer amplifiers that I stay away from.

[Sea Chief]

I stand corrected. It is the solid state newer amplifiers that I stay away from.

No its not solid state, it's all tube including rectifier- but nevermind thanks for your help anyway.

I do have a few gremlins I need to tackle before selling, maybe I can do a separate thread.

[Sea Chief]

I stand corrected. It is the solid state newer amplifiers that I stay away from.

Actually this likely means you are not referring to my amp by 'it'.. ambiguity in action. thx

[g1]

Ok so as to resale value, I guess putting in the 16ohm instead will detract from it's value?

Yes, but so will any mods whatsoever.

[Sea Chief]

Yes, but so will any mods whatsoever.

Id think if I put in a MM xfmr, MM axiom choke (as is the 'tonemod' idea with this circuit) it would surely do so wouldn't you think tho? I was toying with the idea of adding just the choke you see.

A 5Y3, 2x el84, plus the added 12ax7 as 'top boost' is surely one fine 15w amp recipe, & folks say it has great sag & gain tone cranked: trouble is I can never hear it/ never heard it: so I think now little point me owning it tbh it just sits looking pretty- it's better used properly by someone.

Considering an attenuator as a last gasp.. but maybe this will still be too loud, plus might sap the 'goodies' tonewise.

[vintagekiki]

The Celestion alnico blue

https://www.voxac30.org.uk/vox_ac30_celestion_blue.html

[Chuck H]

Well since this is a reissue model and not the more venerable original I don't think you're going to detriment value much with a MM transformer. And anyway, you can always save the original for reinstallation if it makes any difference. If you don't mind the expense and you want a 16 ohm tap there is no other option.

And I don't understand the attenuator option being raised.?. If you're inclined to run a 16 ohm speaker on an 8 ohm secondary it's already been suggested that you don't run the amp too hard. So I don't see how that helps. Unless you were considering an 8 ohm attenuator with the 16 ohm speaker plugged into it? And that still wouldn't help much unless you were operating with a very high degree of attenuation.

[Sea Chief]

Well since this is a reissue model and not the more venerable original I don't think you're going to detriment value much with a MM transformer. And anyway, you can always save the original for reinstallation if it makes any difference. If you don't mind the expense and you want a 16 ohm tap there is no other option.

And I don't understand the attenuator option being raised.?. If you're inclined to run a 16 ohm speaker on an 8 ohm secondary it's already been suggested that you don't run the amp too hard. So I don't see how that helps. Unless you were considering an 8 ohm attenuator with the 16 ohm speaker plugged into it? And that still wouldn't help much unless you were operating with a very high degree of attenuation.

No I wasn't considering a different OT Chuck. The only mod for this amp is called the 'tonemod' involving replacing the mains xfmr with a MM, adding a MM axiom choke. I should imagine if I did this (leaving the vox blue 8ohm in) it surely would add value.. but might not be worth the expense to mod it purely to sell: it might be much effort, just to break even.

On a separate avenue I was considering an attenuator, leaving amp as it is with the 8ohm in, but I've no idea about them. IE will I still have to have an extremely loud amp to be able to get into the 'compression/ sag' goodies? eg will it need to go about 3/4 of the volume to achieve this? or, will it attenuate really well & I need only go say 1/4 the volume to achieve the goodies?

IE is an attenuator only partially effective (still needing significant volume produced to be able to dig into the goodies), or is it highly effective (only needing a bit of volume)? As el84 tubes seem to be less expensive & an abundence of them, maybe if I could get an attenuator situation sorted out, I need not worry too much about cranking the amp if it just means getting through a few pairs of el84's every few yrs.

I think there's a gap in the market for hiring out pedals.. £5 a weekend or something. Then I could conceivably try an attenuator.