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Part refurbished and working. The circuit board was cleaned-up and components visually inspected and tested with a meter. Two capacitors were found to be faulty and replaced. All potentiometers on the front panel were removed, dismantled, cleaned and tested before putting back. Two potentiometers were too far gone and have been replaced by good quality Bourns blue boxes. All controls now turn OK without any static or drop-outs. The cut and boost switches were cleaned and are now working. The amp is running well and sounds good. Suitable for clean tones and blues - achieve a metal sound by using a pedal in front. All components in circuit are working well without any signs of stress. Moderately loud in normal use, switch on the boost for higher volume.

and now for the rest of the listing....

Here is a bit of a strange amp.

I found this recently on ebay and two things caught my eye. Firstly the black Marshall logo, and the model designation of Lead 50. Well Marshall made a solid state Lead 100, but not a Lead 50, so what was this amp?

Having had a close look at it, there are two possibilities. (Well three).

Firstly it could be somebody's project, a home built copy of a Marshall amp from 1975, but not quite the same. Or by the same token it could be something made up by a Marshall employee using Marshall parts that were smuggled past the gates (don't pretend this doesn't happen).

Or secondly it could be a prototype amp made by Marshall in the development of the Lead 100 amp which later went into production.

The more I am looking at this amp the more it appears to be the latter scenario. I am now fairly convinced, having recently lifted out the printed circuit board to take a look at the underside of it, and found the Marshall name in the copper etch. Marshall JM-10 issue 1.

Here is a rundown of some of the features that make this amp special:

The sleeve that the amp is housed in is a genuine Marshall product, no doubt about it. It has the correct Levant Tolex, the Marshall corner pieces, the gold strapping, same type of handle, and the biggest tell-tale sign of all - the sides are finger jointed. If somebody made this at home, then they went to a lot of trouble to do it right. You can also see the dusty outlines where the unique Marshall disappearing feet used to be. These have now, er, disappeared.

So that's the packaging. Next the chassis. It is made of bent aluminium which is then welded at the corners. Marshall was making their chassis out of steel at this point, but this box has definitely been made in a press, not something a hobbyist would have ready access too. They would also need specialist equipment for the welding, not to mention the fact that aluminium welds require a certain amount of skill to do.

The front panel is made of brushed aluminium, gold colour like a Marshall, and the markings for the controls have been screen-printed on. The script for 'Lead 50' is of the same type as other Marshalls of the period. The front panel looks exactly like a 2098 Lead 100 front panel, except this is a 50 watt amp instead. The holes in the chassis and front panel for the various chassis-mount components have all been neatly cut by hand, not stamped out.

On the back of the amp is a substantial heatsink with horizontal fins, similar to what Marshall would use on all of their solid state amps of this period.

The amp has obviously seen a lot of use. The sleeve is bashed about and has tears in the tolex covering. Some of the corners are missing and it has lost it's feet. One of the silver caps for the handle has gone. There are two names painted on the top of the amp - previous owners. I enquired about this from the seller I bought it from, and they told me neither name was known to them, and wasn't even the name of the person they obtained it from. So it's been through a lot of hands.

After a recent refurbishment the amp is working without issues. The circuit board has been cleaned and the years of dust, grime, and residue from smoke machines removed with it. A couple of potentiometers and two capacitors were replaced. So it's lost it's old patina but does now work properly. If any collectors out there are upset about this, all I can say is you had your chance. The amp has been up for sale for over two months.

So anyway, is it a Marshall, is it not? There isn't a serial number, and no factory production label, but the printed circuit board at least has the Marshall brand on the underside. The model 'Lead 50' does not appear in the Marshall back catalogue. But it does seem an odd choice for a Marshall enthusiast to try to self-build. Why this amp, when most people would want to build a copy of one of the early JTM valve amps?

I will leave it to you out there to decide. I will offer this for sale for a short while and if it doesn't attract any interest then I will probably have a go at fixing it up. Which will no doubt mean stripping-down and probably replacing a few parts with new. And maybe tidy-up the sleeve, so any collectors out there who want 'all original' will miss their chance.

I will give a run-down of the various components inside the amp which might help to give a clue to it's origins and the date it was made. Most of the parts with identifiable date codes seem to point to this amp being made in 1973, which pre-dates the release of the 2098 Lead 100 amp by two years.

Have fun with your sleuthing....

50 watt amp built inside an aluminium chassis and housed in a plywood finger-jointed sleeve. Chassis dimensions 705mm wide, 89mm high, 221mm deep including heatsink and faceplate. Sleeve dimensions 730mm wide 120mm high, 250mm deep. The sleeve is made of 13mm (half inch) plywood and is covered in black levant tolex with gold strapping.

The chassis is fixed to the sleeve with two 0BA bolts. The 2098 Lead amp had four bolts, which is more usual. The bolts screw into rivet nuts which are fixed to the chassis. This is correct for this period Marshall amp; later amps had caged nuts.

The handle is of the same type used by Marshall but this one has silver coloured end pieces. At least one other Marshall solid state amp of the period also had this silver handle.

The plastic corners have 'Marshall' embossed across them. They are fixed to the sleeve with screws, not the rivets which Marshall would normally use.

The layout of parts inside the chassis is similar to the 2098 Lead 100 amp, but not exactly the same.

The face plate is made of gold-coloured brushed aluminium, stuck to the chassis. Holes for the various chassis-mounted components are hand-cut, not punched-out in a press.

Marshall logo made of black plastic, unusual for the time. It does not have pins and is glued to the front.

The amp has Marshall JMP knobs, with grub screw fixings and a hollow body.

The amp has a very long 4.5 meter power cable and a white bakelite MK plug.

Arrow mains toggle switch, a known Marshall part.

Schurter fuse holders, known Marshall part.

Square red neon indicator, 40mA, known Marshall part. Wired to secondary winding on the mains transformer.

Mains transformer similar in appearance to other Marshall amps in the series. This one has the code 5013-2. It cannot be removed from the chassis very easily but appears to have a link across two of the pins at the primary side, so it may be able to be rewired for a 120 volt supply. The amp runs with 32 volt power rails, which is lower than the 100 watt 2098.

AEI Semiconductors PH7A 6X bridge rectifier, known Marshall part. code 7328 (28th week 1973).

Erie 4700uf 40v DC power smoothing caps. Code KA3098T 73 33 (33rd week of 1973).

Printed circuit board is made of pale green fibreglass. The board measures 18 inches by 5 inches (457mm x 126mm). On the underside is the Marshall brand name and the designated part number JM-10 iss 1. The layout of components resembles the 2098 Lead 100 amp but not identical. The circuit in the preamp stage is very similar. The board has lots of evidence of reworking. Components are grouped together in their stages with gaps between each stage. These gaps can also be identified in the circuit diagram for the 2098, but not on the circuit board for the final production amp.

All the original control potentiometers were made by Piher and had pins for PCB through-hole mounting. This is not usual for Marshall, but there is a video on youtube showing the repair of a 2098 Lead 100 amp, and that also has Piher pots. The Piher pots have codes 8548 or 8547. Two of these pots have now been replaced with ultra reliable Bournes blue boxes. The old pots will be included in the sale in a plastic bag, if any collectors out there want them for their mantle-piece.

The slider switches are known Marshall parts, these have codes SSP 225R.

Jack sockets by Cliff and Rean. The jack input sockets are unusual for a PCB mount - these are jack sockets with solder tabs and the tabs go through slots in the PCB and are folded down and soldered. So not the usual jack sockets with pins - maybe these were all that was available at the time.

Motorola Darlington transistors in the final output stage. MJ2501 code 323, MJ3001 code 353.

Output auto-transformer 292-492, same as the one used in the 2098 Lead 100.

Rotary switch for selecting speaker impedance, unknown brand, and not of the type usually found in Marshall amps.

Components found on the PCB and are known Marshall parts include:

Resistors by Piher and Iskra.

Erie caps 25uf 25v, codes 20101 HWH (1969 ninth week).

Erie cap 1000uf 25v codes 21105-100 WYI (1970 eighteenth week).

Philips aluminium electrolytic caps 22uf 25v for coupling stages.

Mullard mustard caps

47n 400v

22n 400v

various tropical fish caps

Dog bone caps

100p

47p

KE3819 FET transistors on input stage (same as 2098 amp).

BC184c

BC212B

BC184L

MPSA06

Motorola semiconductor MD8003 code 7252 (dual transistor same as 2098 amp).

Wiring used is a mixture of gauges, soldered straight to pins. In Marshall amps of this period it is usual to find a method of strain relief by threading through holes in the PCB, over and under again. Some of the wiring is on rainbow ribbon cable, not usually found in Marshall amps.

Fixings are made of brass with a mix of domehead, cheesehead and countersunk screws.

As a final curiosity, there is an additional Erie 4700uf electrolytic capacitor situated between the two speaker output jacks. This is not connected in circuit. Possibly a left-over part, used to couple the amp to the speakers, but not needed with an output balancing transformer.

Please study the photographs for further details of this strange amp.

++++ NEW INFO ++++

There is a video on youtube showing the insides of a Marshall Lead 100 as it is being serviced. The circuit board layout on that amp is very similar to this one, although the amp in the video has a more finished PCB with components marked-up. So going by that video it looks like there were at least two versions of the Lead 100, and one has a PCB which is close to the one here, and is a documented Marshall product.

I have put a price of £400 for this amp, use your judgement to decide whether or not it originated from the Marshall factory.

Postage charge is £15 for a UK mainland address, which is both tracked and insured.

I will accept purchases from certain overseas countries - those that continue to have decent buyers. I have had bad experiences from other countries in the past so those are now excluded. Sorry to do this, blame your dishonest fellow countrymen.

Overseas shipping will be through ebay's global shipping programme. This is a service provided by a third party shipping agent, and I have no control over what they charge, so no grumbles or rotten feedback for me please.

Amp offered for sale in as seen, spares or repairs condition with no guarantee of it working properly. No returns are accepted. Whether or not this is a genuine Marshall product is down to your own decision, use the information provided above and the photos for guidance.

If anyone can supply any further information I would be interested to find out. Please send emails with questions.

I am currently clearing out some space, check out my other listings for more stuff.

Thank you!

Routine small print follows....

The item is located in Dalston in East London, E8 postcode. This is close to the centre and within the ULEZ zone.

Payment expected within 5 days.

Payment with ebay managed payments or paypal or cash on collection.

The postage charge quoted is for UK mainland delivery. If you live on an island or some other far-flung place like the Scottish Highlands then confirm the postage rate with me first. If your postcode is classed as a remote area then the courier is very likely to surcharge for delivery and I will need to pass this price on to you. Email first if you think this might apply to you.

Please read the item description and take a close look at the photos so that you are fully aware of what you are buying. In particular take a look at any faults in the item that I have pointed out.

The sort of things I sell on ebay tend to be music or audio related. Out of this, just about everything is either hard to obtain or long discontinued or out of production or just generally rare. It does not need to be rare and therefore expensive, but I put things up for sale which I know are difficult to find in a regular audio store. I could just chuck them in the bin like most everybody else, but I just have this feeling, that somebody out there might want to own the sort of things I sell. It might be some use to them, or it might have some nostalgic value. But that does not mean that I will plug away and list the same thing week on week. There has to come a point where I accept that the thing needs to go. So if it does not sell then it might well end up getting broken up for parts or just ditched in the bin. The best policy, if you are on the lookout for this particular item and you see that I have got it, then just buy it or bid on it if it is an auction. Don't say 'oh he's going to list it again next week at a cheaper price and that is when I will buy it....' because honestly it might never happen. When it's gone it has gone.