GlamBass74

defeat admitted ☹️ Almost threw it out, but have decided to send to my local company who do that sort of thang I was out of my depth knowledge wise and realised that i'd probably end up spending hours throwing components at it before throwing it in the bin anyway I will update when it returns as to exactly what was wrong with it. If the estimate to repair is too high, then I will fit a speakon socket to the cab and use another amp with it instead. Watch this space

Well..... Transistor fitted and well pasted Fired up and test driver shoots forward and hums. Tested the voltage at the speaker terminals and its DC (17v from memory) Hmmm..... this isn't going to be straightforward Where might I begin looking if i'm seeing DC at that point? Jon

Hi Thanks for the great reply I've started doing some CAD work to see what's viable I've always found with WinISD that the port calculations seem to come out longer than actually required after the infamous rice test (love the simplicity of that idea) This is with both round port and shelf ports. I'm starting to think i'm doing something wrong. I will definitely look into the tuning aspect of the enclosure a bit more. One of these bridged through an ancient (and heavy!) PV900 with the low cut engaged might be rather pleasant Cheers!

i'm leaning towards 80L nett tuned to 45hz Not huge to transport, but a decent response I reckon one of these would be good for pub gigs Now - how to calculate a shelf port... Thanks for the info Phil

@Phil Starr - i cant wait to see it! I've been checking daily 😅

The hole that the transistor pokes through... Fill it up so it radiates heat to the sink?

Indeed. Thank you. My BMW bike uses it beneath the CDI unit, so fortunately I have some. COVID came to play today so I'm not going to be working on the amp for a few days ☹️

Thank you. I had ordered outputs transistors and resistors I have also ordered the transistor in question. Appreciate your help 👍

The item in question seems to be an MPSA13

Superb. Thank you. Stuff to look at. I powered it up this evening and found it's a transistor producing the smoke. It lives in a hole in the heatsink near one of the power transistors. I've taken it out.... It's in the second pic. Near the third from the left transistor covered in white goo. I've repaired the headphone socket. The contacts now make when the 1/4 plug is removed. Now to look at the schematic and see what this burnt part should be. Cheers!

LONG POST WARNING Hi All Bought an Ampeg B100R yesterday for a very, very low price Was listed as spares or repair, so in my mind i was going to rip out the amp and fit a speakon on the back like I did with my BA115HP (again bought as spares or repair a few years ago) Got it home and marvelled at the condition for the cost of approx 4 beers and then decided its a bad move to just ditch the amp section Symptoms... Power on - no power. Dead as a doornail Opened up amp and the 1.5A slow blow was pooped. Checked with a multimeter. No continuity - Ooooo result, but why??? New fuse, switched on... hummed a lot and it released a little bit of the magic smoke after around 10 seconds bummer. Looked like it came from around the transistors, but cant be sure. Will investigate later. Fuse didn't pop and it still fires up even after losing the smoke..... So..... I've now removed the amp completely and am thinking it might be fun to work through it First things first.... Light bulb tester.... Should I consider putting one together? I am thinking of teeing a bulb holder into an IEM cable. I'm thinking i'd need a 100+ watt bulb to make it work properly. Are these rare items these days? Grille is held in with velcro pads. Persuaded out with a flat blade screwdriver and hope. Will staple a fabric tab on the frame to enable me to pull it out easier next time (next time????) Speaker is fine - tested with another amp and works well. Apart from the dust it looks mint. Code is 86-118-14. 4 ohm. Looks very Eminence..ish My initial prodding with a multimeter seem to indicate the there's a few 0.33 ohm 5w resistors that aren't showing anything like their correct values. The transistors 2 x TIP142 and 2 x TIP147 seem to show the same readings per "pair". Will remove them later and test them individually I've purchased some new transistors, some resistors (£6 so far) and i've downloaded the circuit diagram for the amp I have a multimeter, a yoghurt pot half full of common sense and a desire not too end my life too early. If anyone would like to chip in, then please feel free. If the response is send it to a professional then please save your typing. I can't warrant spending too much on it. My time is my own and learning is good. If it takes me a few months, but I learn from doing it, then i'll be a happy bunny. If it takes months and it does my head in to the point where I launch it across the garage, then the speakon socket will be installed in the cab and the amp module thrust into the bin in disgust 😁 I'll add to this thread as I discover/damage stuff Jon

A sub you say???? oh..... how very timely Yes please! Still my fave driver.... Can't believe theyre discontinuing them ☹️

I'm currently contemplating building a "modular" setup of dinky 1 x 10 cabs loaded with Beyma 10CMV2 drivers (thanks @fleabag) 1 for home/rehearsal - 8 ohm 2 for small pub - 4 ohm 3 in a column with a strap round them for a bigger pub - 2.66 ohm 4 for outdoor in conventional 4 x 10 format - 2 ohm 30L enclosures made from 12mm ply. Toolstation manrose pipe porting and Rustin's step paint finish (see? - i'm cheap!). May even skip a tweeter on the first to see how it sounds. This way I can take what I need. I've sized the design to slip into a cheap Thomann cajon case. Bit of protection and the ability to carry like a rucksack.... 3 can be cut from an 8 x 4 sheet My partner is overjoyed at the prospect of more cabs in the spare room I'm such a nerd.....

I'd look ridiculous playing mine - i'm not a small chap (but then again, this is a man that rode a Honda 90 from Norwich to John O Groats and back so anything goes really) I think it'll be a home playing only bass 😁 Might even lush it up with a new set of strings..... 'bout time

I cleaned mine up last night and tried it - SUCCESS! What a strange tone. Very "thunky" - really quite nice A bit crackly, but nothing I cant fix

@neepheid Hurrah! some good vibes! Yep... 20mm wide copper tape Good lighting Scissors Tea/Coffee/Cocktail Soldering iron (to remove and replace wiring) Meter (to test that all strips/cavities/parts have continuity) Spanner to remove pots & jack socket Screwdriver It was a strangely rather enjoyable job Just checked....My copper tape was £6.99 for 20m. I probably used about 500mm 😁 I don't know the science behind it all, but I really don't care. I did it. It works. I'm happy

I just had a look at that - brilliant! Thank you Its certainly not something i'd consider using, but I just can't get rid.... Pointless really, but i'm a bit like that 😁 Thank you everyone for your comments. At last I actually know what it is! 👍

Hi All. Can anyone shed any light on this beast? I've had it in my loft for about 30 years. Any sensible info appreciated! 😁

thanks Bunion - i'm chuffed ☺️

Not the prettiest, but it works a treat!

The bridge had a wire fanned out beneath it that was earthed on the back of a pot I also put copper tape beneath it as well as the wire I made a copper tape "wire" to run from the pickup cavity to the control cavity and made sure I had continuity between them Passed between each cavity and taped in place I overlapped the tape from the cavities to the backs of the scratch and pot plate so they had continuity when screwed back on It wasn't super pretty, but it did a good job. I wasn't expecting the improvement I got.... It really has transformed the old girl I will definitely be gigging the old girl now ☺️

Helloski I bought a Harley Benton Jazz copy in the Summer of 21 purely out of curiosity. £139???? It's gotta be rubbish hasn't it? Err , no! Natural finish Vintage Series JB75-MN Apart from it's sheer heft, I love it. Love the look and love the way it plays There's one thing that's been bugging me though. Playing... no buzz. hands off strings..... buzz! I bought some 20mm wide copper tape from Ebay and last night I set about shielding the body (no provision for shielding whatsoever on this from the factory) About 2 hours to do it all, link all cavities, cover back of plates, test with a meter and stick back together Now - Perfick! I know i've not re-invented the wheel, but what a satisfying job to carry out. Even made The Apprentice bareable to watch (where do they find those people???? ) So... Happy Glambass That's it really.... Bye! Jon I

Hi. I didn't plan on one, but I'm only at the winisd stage at present I will have a think about it.