Thunder 1A (Version1) pickups and preamp

Electrical gremilns sorted, I'm really enjoying my new Thunder 1A. The diversity of tones available is really incredible with all the pickup switching and active control options.

Being a 1981 mode, I guess the pickups would be the HF450 ones that were used in the early Thunders? They are not bad and sort of suit the guitar but are can perhaps be wee bit bass heavy. Has anyone replaced the pickups on a Thunder and what did they use?

Personally, I really like seymour duncan 59's which are available with a 4 connector cable so would be compatible. Quite expensive though and there is also a lot to be said for keeping the guitar original since it is a bit of a minter.

I've also noticed that switching into active mode creates a wee bit of tone suck when the tone knob is set at the centre ident. I'm curious if this might be part of the intended behaviour. Does anyone have a schematic of the active pre-amp?

Cheers,

iep

iep wrote:Being a 1981 mode, I guess the pickups would be the HF450 ones that were used in the early Thunders? They are not bad and sort of suit the guitar but are can perhaps be wee bit bass heavy. Has anyone replaced the pickups on a Thunder and what did they use?

Personally, I really like seymour duncan 59's which are available with a 4 connector cable so would be compatible. Quite expensive though and there is also a lot to be said for keeping the guitar original since it is a bit of a minter.

Interesting - I can't quite remember what the relationship is between the F450, HF450, Hammer I, & 45 pickups, but I've always found the Hammer I (apparently in my Thunder I-T) & '45' (in my Pantera) to be on the 'toppy' side of things, to be honest. I guess it's the active circuit in yours making the difference?

Regarding swapping for an SD '59 - I did exactly the same with my Pantera in the belief that an aftermarket pickup would obviously be better than stock. The '59 was good, but when I switched them back again after a year or so, I much preferred the original!

F450, Hammer I's, MMK45 are all the same just sales rap.

Here's an interesting little mod.
http://forum.westoneguitars.net/t5338-mmk45-magnet-swap

Westbone wrote:F450, Hammer I's, MMK45 are all the same just sales rap.

Here's an interesting little mod.
http://forum.westoneguitars.net/t5338-mmk45-magnet-swap

I suspected that was the case, but wasn't sure (I also see why it looked weird when I wrote '45' now - I forget about the MMK bit )

Where do you get the replacement magnets from, by the way?

What punkyjam67 said. Where do you get the magnets? There's a few magnets available on eBay but I'm not sure what size etc I'd need. These for example?

http://www.ebay.co.uk/itm/Alnico-2-3-5-Bar-Magnets-2-pcs-Rough-cast-MAGNETISED-2-5-x0-5-x0-125-UK-STOCK-/272118446242?var=&hash=item3f5b85f8a2:m:mOwyXHxunfFpwzr3vGt5xKA

Cheers,

iep

They'll do.

Or these, even cheaper.
http://www.ebay.co.uk/itm/111342048609?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

Keep it local, and cheap. Cermag get good rep. 
http://www.cermagmagnets.co.uk/guitar-pickup-magnets-11-c.asp

Damian, what's your take on "rough" versus "polished" mags? Is there appreciable difference in tone/clarity?

Sgt. VimesThat makes total sense, thanks man!

I should have bought the UK based A II pair when I had the chance, but ordered some from across the pond,

Barry wrote:Damian, what's your take on "rough" versus "polished" mags? Is there appreciable difference in tone/clarity?

To my ears, nothing!

Sgt. Vimes wrote:Keep it local, and cheap. Cermag get good rep. 
http://www.cermagmagnets.co.uk/guitar-pickup-magnets-11-c.asp

They are cheap + local. Good selection too.
Excellent!..

Great selection! With all the sizing options I'm just a bit stumped as to which magnets will physically fit best. Westbone, don't suppose you still have he originals to measure?

Other points.

Any reason you did not try Alnico V? I like the bright slightly scooped sound of the 59s and apparently this is characteristic of Alnico V.

From the photo in the magnet swap thread, it looks like the magnets are not wax potted in place and slide out quite easily?

Daft practical question. Were you able to reuse the pickup tape? If not, where would you buy such a thing?

Thanks again for all the useful info.

Cheers,

iep

The tape should be reusable, but if it's past it's sell by, try this stuff, yes it's not local...(the shame!) but it's cheap and good quality, I've used this a few times now and it doesn't come unstuck.
Postage will be around £5 so best to pick up a few bits while you're at it.

Edit: a link would be useful.....

http://www.eyguitarmusic.com/13mm30mCloth-Black-insulation-tapefor-Wrapping-Pickup-Coil_p_1334.html


I don't know for sure, but this stuff looks ok.
http://www.ebay.co.uk/itm/25mx19mm-TESA-TAPE-ADHESIVE-CLOTH-FABRIC-WIRING-LOOM-HARNESS-TAPE-CABLE-ROLL-NEW-/291673276596?hash=item43e91500b4:g:oiEAAOSwGiRTrJLt

I use this tape all the time  9mm, just my preference.
http://www.ebay.co.uk/itm/25m-Tesa-Adhesive-Cloth-Fabric-Wiring-Harness-Loom-Tape-Cable-Roll-9mm-15mm-19mm-/400528034131?var=&hash=item5d4154c953:m:m7ZgVvuB0M5PMLpKDQPziTQ

As for the magnets, use whatever strenght you like!

Originals are approximately 60mm in length x 12.5 width including bar.

Ah it"s nice to know that tesa tape is ok,  I know it's used in automotive wiring looms,  but wasn't sure if it'd  be suitable,  cheers!

Oh and cermag postage is around £4.

All ordered! Went for double height (I think they'll just fit) Alnico Vs and the tape off of eBay.

As ever, ta for all the input. This guitar is an education if nothing else

I'll hopefully get a chance to fit them end of next week. I'll post back with results.

Cheers,

iep

Cheers fellas, all good stuff - I predict a bit of experimentation in the near future

Westbone wrote:F450, Hammer I's, MMK45 are all the same just sales rap.

Here's an interesting little mod.
http://forum.westoneguitars.net/t5338-mmk45-magnet-swap

Hi Westbone,
                   On your comment above, the Westone bible site:

http://www.westone.info/thunder1.html

Describes the F450s as 'two magnet pickups'. Your MMK45 magnet swap post only shows one magnet. Is it possible the F450s are different after all?

Cheers,

iep

iep wrote:

Westbone wrote:F450, Hammer I's, MMK45 are all the same just sales rap.

Here's an interesting little mod.
http://forum.westoneguitars.net/t5338-mmk45-magnet-swap

Hi Westbone,
                   On your comment above, the Westone bible site:

http://www.westone.info/thunder1.html

Describes the F450s as 'two magnet pickups'. Your MMK45 magnet swap post only shows one magnet. Is it possible the F450s are different after all?

Cheers,

iep

How many pickups does the guitar have?

That's the  old site not our one. How dare you look there....
Here's our one, the better site.
http://www.westoneguitars.net/

iep wrote:http://www.westone.info/thunder1.html

Describes the F450s as 'two magnet pickups'. Your MMK45 magnet swap post only shows one magnet. Is it possible the F450s are different after all?

Need to watch out for the capital letters & hyphen there, mate - the pickup was called a 'Magnet-F450', I believe. So, like Westbone says, a Thunder has two pickups, so it has 'two Magnet-F450 pickups'.

Haha yes, that hyphen really matters.

Tried out the Alnico Vs (62mm, 12.5mm, 3.5mm) and I have to say I like them. Definitely better than the stock ceramics to my ear.

Reduced output or maybe just less compressed which gives a nicer detailed tone. Little bit more top end generally and the single coil sounds are just, well, more single coil.

Once you haver the pickup tape off it's a doddle to fit the new magnets. As Westbone says though, be sure to note the orientation. I forgot on my first pickup but was able to work it out by lining up the glue marks on the old magnet with those on the pickup chassis.

All said though, while better, they have not quite got the tone where I want it to be. I will be saving up for a Seymour Duncan SH1N and JB SH4. I reckon they will sound tremendous in the Thunder.

iep

Bit the bullet and bought the SD pups as above. Nice and easy to fit with the handy wiring diagrams provided on the Westone sites.

Guitar now (to my ear) sounds epic. Huge articulate neck pup sound, proper rock tone from the bridge. Relatively low impedance windings make for great clean tones too. To my mind they are a good match for the guitar. Very pleased.

With these pups the difference in tone between the passive and active modes is more apparent. Seems like there is some high freq roll off included in the boost circuit so even when the treble is boosted, the very top end is missing compared to the passive mode. Basically a mid boost sort of vibe. I guess if you understand it and use it as such it is fine.

FYI, I spent quite a bit of time attempting to trace the preamp circuit but it is unlike any op-amp topology I have seen before.

Cheers,
iep

Re the pre-amp circuit, would it be that hard to make one from scratch?

It's just a load of resisters, capacitors, transistors and the like assembled on a printed circuit board. And circuit boards aren't that hard to make if I remember back to my school days. I thnk we put nail varnish on a sheet of circuit board material and dipped it in acid...

All the other components should be readily available. You just need someone to draw up what goes where...    

You're right enough, a simple clean boost with EQ is not too difficult a circuit to design and it would mock up fine on Vero board.

That said, you'd want it to integrate with the existing pots/switches which places some constraints and makes it a little more complex. The multiplexed tone knob (same knob for both active and passive modes) is quite elegant and it is not totally obvious to me how the switching is achieved. That's why I wanted to map out the existing PCB and possibly redesign from there.

As I say though, if you accept the existing boost for what it is (EQ/boost with a bit of mid boost) it works very well. I'm not sure if there is enough impetus to design a whole new one just to get a wee bit more top end sparkle.

Cheers,

iep