Original 1959SLP Super Lead Died. Help?

[rorystrat]

Hi

I think this is my first thread here. Yesterday my original 1959SLP from 1969 that I bought used in 1973 died on me. In recent years when I played it, it banged, boomed and crashed enough for the dog to think it was thunder and lightning. I bought an attenuator and could play it at a volume that did not freak the dog out and for which the bangs were tolerable. Yesterday it sounded great on 3/4 volume with attenuator or 5% but just died. There was no bang or smoke and the light was on so the mains fuse had not gone.

When I first got it out of hibernation a few weeks ago, I took the chassis out (before I'd put any juice through it) and it looks all original to me. I've never had it looked at but did change the valves at some point in the past 50 years. I've been very wary of taking it anywhere in case I was told it was all obsolete and everything needed replacing and/or it has rare and valuable components that could be replaced without me knowing.



Is this a scenario anyone recognizes? Is it terminal or an easy repair? Would it be costly and would it sound anything like it did before after upgrading? I do have a 1987X reissue so am not totally lost but as a pensioner now wonder whether it's worth the cost repairing? Help. Peter

Is

 

[Spanngitter]

That unit seems indeed to be completely untouched since `73. However, can you pls be more specific on "just died"?
Did it shut off immediately or did the sound fade away? Have you checked your HT (1A) and Main Fuse (4AT)?
Are you familiar with using a DVM?

 

[black knight]

Greetings and welcome to the forum!

First, yes, it is most definitely worth repairing. No question. Second, wow, what a stunningly beautiful amp you have there. I bet it sounds glorious. And lastly, we have many experts on this forum who will no doubt assist you in getting it up and roaring again, so don't worry.

FWIW, I had a 1970 1987 lead head that just quit on me one day. I took it to the tech and he hooked it all up and it worked flawlessly. He troubleshot and troubleshot, but just couldn't figure out why it quit working. Eventually he gave it back and when I got it home it worked for some time and then quit working again. In retrospect, without knowing anything about voltages and cap residual charges, I went poking around inside. I do not recommend doing this. In any case, I managed to figure out what the problem was. It was was a loose ohms selector wire due to a poor solder joint causing intermittent loss of output. Of the many things you have your tech check, this might be worth checking.

Hang in there, you'll get this sorted out. You came to the right place.

 

[Dr.Twang!]

Did you check HT fuse? What does the note on side panel say about H.T. circuit? Beautiful insides!

 

[paul-e-mann]

Hi

I think this is my first thread here. Yesterday my original 1959SLP from 1969 that I bought used in 1973 died on me. In recent years when I played it, it banged, boomed and crashed enough for the dog to think it was thunder and lightning. I bought an attenuator and could play it at a volume that did not freak the dog out and for which the bangs were tolerable. Yesterday it sounded great on 3/4 volume with attenuator or 5% but just died. There was no bang or smoke and the light was on so the mains fuse had not gone.

When I first got it out of hibernation a few weeks ago, I took the chassis out (before I'd put any juice through it) and it looks all original to me. I've never had it looked at but did change the valves at some point in the past 50 years. I've been very wary of taking it anywhere in case I was told it was all obsolete and everything needed replacing and/or it has rare and valuable components that could be replaced without me knowing.

View attachment 127123

Is this a scenario anyone recognizes? Is it terminal or an easy repair? Would it be costly and would it sound anything like it did before after upgrading? I do have a 1987X reissue so am not totally lost but as a pensioner now wonder whether it's worth the cost repairing? Help. Peter

Is

So it hasnt lost power or fuse blown but no sound, I'm gonna guess you lost a preamp tube. Take a known good preamp tube and cycle it through your preamp slots to find the bad tube.

 

[playloud]

That amp is very clean indeed!

Agree about checking HT fuses and preamp tubes. It's most likely something simple. Be wary about taking an amp that pristine to a tech.

 

[rorystrat]

Thanks all for the responses.

Just a bit more of the back-story first. When I first got this amp, when I was 16, impatient with my enthusiasm and excitement, I turned it on and played it without a cab attached. I could hear the valves singing along - then it went bang. I replaced the HT fuse then and it worked again. But I've spent the last 50 years worrying whether I'd done some lasting damage. I've assumed that this might be the cause of the banging and crashing sounds and when it packed in recently I thought that might be some major component giving out. I've rehearsed with the amp but don't remember ever gigging with it so it's not had too hard a life in my ownership.

So following on from your responses, I did indeed look at the HT fuse that I put in 50 years ago, and that was definitely Kaput! So I ordered a pack from a well now internet auction site and stuck a new one in. Lo and behold it works again! I got a pack of 10 so at this rate I've got enough to last me the next 450 years.

There remains the problem of the banging noise so I wondered if anyone has an idea what's causing that? At the time it went, I had it on full throttle through an attenuator trying to get the Mick Ronson tone for Ziggy Stardust.

In the meantime I'm lovin' the tone of my 100w Vintage Modern that I did buy to gig with when they first came out but have really never bothered with it much.

 

[Pete Farrington]

There remains the problem of the banging noise so I wondered if anyone has an idea what's causing that?

The first thing to eliminate, especially as a HT fuse has popped, is it being due to a bad valve.

When I first got it out of hibernation

If the electrolytic caps haven’t been charged up for months, it’s a good idea to follow a staged power up power up procedure. This gives them chance to reform their internal insulation whilst mitigating the risk of damage.
See https://www.londonsound.org/Vintage valve hi-fi.htm

I noticed the ‘rory strat’, is that a reference to Rory Gallagher?

 

[rorystrat]

I noticed the ‘rory strat’, is that a reference to Rory Gallagher?

Thanks Pete for the tips on the amp. and yes I am a big Rory fan though having had a Strat most of my adult life I now favour a Les Paul. I did rehearse as a Rory Gallagher tribute but never gigged as such. Paul Kossoff and Peter Green are my main interest though I have again spent tonight admiring Mick Ronson's live tone. Don't think you can beat Koss's tone though.

 

[rorystrat]

If the electrolytic caps haven’t been charged up for months, it’s a good idea to follow a staged power up power up procedure. This gives them chance to reform their internal insulation whilst mitigating the risk of damage.

Thanks. I’ve read the link you attached which scared me a bit. I did not do this with any of my amps and I’ve not gigged since 2012. I’ll leave the 1959 for a while and follow a staged power up. It’s currently not plugged in.


Nothing else is as vintage as the old 1959 but all are over 12 years old. They seem to be working fine having been resting for a while. Oddly my Orange Tiny Terror on 7.5 watts is as loud as the 100w Vintage Modern.

It occurred that maybe the 1959 didn’t like the attenuator. Is that a known problem? I bought the cheapest I could.

 

[Matthews Guitars]

I would never recommend buying the cheapest attenuator you can find. Invest in a quality one. A Marshall Power Brake is the minimum level unit I'll trust.

A cheap attenuator (and even some more expensive ones) can and will kill an output transformer. Ask people who lost their transformers to a Tom Scholz power soak.

Running the amp with no speaker connected for a brief period MAY do damage, and then it may not. But run it with no connected load for any length of time, and it WILL do damage. I blew an output transformer recently in my favorite Marshall, and it was due to a connection that hadn't been soldered. Nobody's fault but mine.

 

[V-man]

If the electrolytic caps haven’t been charged up for months, it’s a good idea to follow a staged power up power up procedure. This gives them chance to reform their internal insulation whilst mitigating the risk of damage.
See https://www.londonsound.org/Vintage valve hi-fi.htm

This. Marshall manuals were never that good to begin with but no manual addresses what to do 20+ years down the road.

You HAD an amp years ago. Those days are gone… you now HAVE a relic that demands certain attention if you want to keep it healthy and/or preserve its value.

1. You do NOT let an old tube amp sit up for months, much less years. In the case that happens, you sure as hell don’t flip it on like it’s been last week. You learn how to trickle in some juice to the caps slowly over time or better yet, take it to a competent tech who can check it out thoroughly.

2. Your caps are probably on their last legs as is and the sudden power stunt didn’t help matters. Some argue replacing caps is sacrilege if there is no obvious signs of damage and others argue they are like tires or a timing chain, meant to be replaced over time. Needed or not, I replaced the caps on my ’78 when I got it 10 years ago. Whether replaced or reformed, a tech needs to see the amp… your crisis today MAY have been averted today with a new fuse, but you quite likely have one looming this week/next month/etc. with a long-sitting unserviced amp that just took a hit for unknown reasons.

3. The attenuator had best be a quality unit. Ever heard of Paul Walker? Aside from his tragic death in the process (along w the driver’s) this is the tragic story of a legendary Porsche riding inadequate tires. Proper (healthy) valves, caps, fuses and absolutely… sturdy attenuation is necessary.

4. If you don’t love this amp (play often) or have a child that does, consider selling it. The idea you could blow a transformer through neglect from inconsistent use and lack of service is tragic. They are valuable and can someone else’s headache to preserve. You can certsinly get something you would use more often with some money put aside from the sale While you enjoy the 1987X.

 

[rorystrat]

Marshall manuals were never that good to begin with

More food for thought guys. I do have the manual for the 1987X which also covers the 1959SLP. The only relevant reference in it is point G: "ALWAYS unplug this apparatus during lightning storms or if unused for long periods of time". Nothing about a staged power up if unused for long periods. So if this is received wisdom, and that does make sense, I'd not heard of it till now.

I looked at a Power Brake years ago but I think I concluded that for the price I might as well buy a lower powered amp. I have the Orange Tiny Terror for home practice but now I'm of retirement age, thought I'd like to use the bigger amps at home too but without taking the roof off. Hopefully I haven't done any lasting damage (too the amps not the roof).

 

[playloud]

The point about the cheapest attenuator you could find does worry me a bit. Which model is it exactly?

I understand the reticence to spend big money, but Power Brakes can still be found reasonably cheaply in the UK (at least <£200). Compared to the potential loss in value from a failed transformer, that's a bargain!

Also, a minor niggle... "1959SLP" is an anachronism. They introduced the "SLP" part with the reissues (an abbreviation of "Super Lead Plexi", "Plexi" itself being a description that was used well after the originals had stopped being produced). Yours is simply a "1959" or "Super Lead".

 

[myersbw]

Here's a few suggestions to add to the pot! And, congrats on retirement!!! I just joined that rank a year ago and it sure is freeing, right???

So, you're blowing HT fuses and hit bangs. I'm also seeing red-based power tubes as I peer at the center post protruding through the power tube sockets. Very cool, but just how old are those tubes? If you say "ancient"...get a new quad. (GULP, they are not cheap these days)

The banging. Well, that can be a few things. The two most prominent are going to be oxidation on jacks & plugs & tube sockets and tubes failing with shorts (basically a little metal breaking away with vibration and some arcing happening).

As others have testified, that amp is absolutely worth fixing. Second, you asked how much you could be in it for. Ok, now I'm going to give you a very rough price range given what it might be and with respect to the fact I do amp repairs...BUT....I work out of my home (not much overhead).

I'd give it a complete maintenance routine...clean the pots, inspect and clean the jacks with DeOxit. Replace as needed. Replace all power filter caps, including the bias circuit caps. Install a new quad of power tubes and bias. Test the preamp tubes and replace as needed. I'm approximating and estimating shipping, etc., it'll vary. I use tubesandmore.com a LOT.

Quad of E34L's (JJ) - approx $135
F&T caps - approx $80
bias & routine maint - $140 (padded it by $20 if a few jacks, etc. were needed)

So, about $355 or so. Some places double the parts costs or add a minimal/hourly charge. Bad 12ax7's will add to the cost, too.

Now, don't fret this yet. If and ONLY if you're competent with a soldering iron and a minor bit of maintenance and cleaning. You need to know how to drain the capacitors' stored charge. If so, it's entirely possible to swap out that capacitor bank if you can follow a schematic, etc. However, since you asked here, I'm guessing you aren't skilled in those areas.

I'll assume that what you can do is this...buy a quad of power tubes and replace them. Replace the B+ (high voltage) fuse. Connect the amp to speaker direct with a known good cord. Volume control down...and do the following:

Set the amp so you have a really good view of the tubes. Darken the room, power up and watch & listen. First, we don't want to see those power tubes glow a very dark cherry red (redplating) on their plates...I've seen it very brilliant on an EL84). That indicates too much current and a bias adjustment is in order...power down and get it biased. Second, you're looking for very small brilliant flashes (sparks) in any tube. That indicates shorts are happening. That can associate with the bangs (as can oxidation at cords & jacks).

Third, if any of the previous (especially red plating)...shut the amp down. No? Proceed. Next, a very light tap or slight pressure at every tube (I use a nylon adjustment tool...a pencil can work, too.). Hear a bang or otherwise? That can indicate the tube or respective socket pins have excessive oxidation. If you don't hear anything with that round....increase the volume control to 3-4 and repeat. Any 12ax7 exhibiting that style of noise is an easy swap for you. Replace and repeat testing.

As for observation tests, 15 minutes should reveal it if not before, regarding power tubes.

If not competent as a tech, buy & replace your power tubes, purchase 1-2 12ax7's (you avoid markups) and take it in to a tech for routine maintenance and bias of power tubes. While there, ask for a quote for power cap replacement.

After your description, I'm assuming you're pushing the power tubes way too hard for their age and one has weakened to the point of over-conducting and blowing the B+ fuse. (I.E. power attenuating while playing at 3/4+ volume and beyond.).

Your cost may be less or more. If you replace those power tubes...PLEASE, get it biased properly. Also, get a decent attenuator (quality cables) if you continue to play in that manner. Charges are now pretty steep due to tube costs. You can find the reasonable/reliable techs by asking players in local bands where or who they go to. I get new clients solely by word of mouth, Players are the best advertisement for us part-time techs that have been doing it for years. Your mileage may vary at some brick & mortar locations. For individual techs, ask for references...the good ones will gladly reveal.

Ultimately, if a fuse replacement lets you minimally power up, I'd hope to see an under $400 USD overhaul (closer to $300 or so including tubes...but brick & mortar places will be high).

Again, I've worked from my residence, so I charge in favor of repeat business and to minimize your sadness. :O I don't have to rely on a lease or benefits, etc. I still contend...that amp is worth a repair...even if only to sell. All the best!