Phil Starr

Please don't try running it if the fault is present, you could go on and damage the amp further. I've had to repair a couple of amps with similar faults and it is no fun at all getting the contents of a large capacitor off the circuit board and other components. You could write off the amp as an economic repair.

This is strangely reassuring. All the time in the world to do the things i want and I'm not motivated without the pressure of performing live. Recently a fellow band member started doing some recording and asked me for some bass and bv's. My goodness I'm so rusty. That's at least motivated me to go back to maintenance mode where I do enough bass playing not to get any worse but that's it. I'm trying to motivate myself a bit by rehashing some of the fun songs I played years ago that I don't have an opportunity to play now. I still think it likely that we will be back playing at least open air gigs this summer, this will come to an end so hang in there everyone. The lower the infection rate now the better chance we have long term. Good luck everyone.

It's really hard to diagnose a fault from a distance particularly an intermittent one. However when it happens you say it is unaffected by the controls. This means it is happening after the pre amp stages or possibly in the power supply. Thunder implies a loud and changing sound so my guess would be to look at the power supply capacitors first. On an old Peavey they may have leaked and this can be obvious sometimes. However the power supply caps can provide a nasty, potentially lethal shock, even when the amp is unplugged. Probably one for a tech if you don't know what you are doing.

C'mon guys give them a break. It's a publicity thing. I see they are offering custom builds and designs too, maybe this started off as one of those. If Barefaced suddenly and unexpectedly offered an 8x15 we'd all be hooked into it. I'd absolutely love to play in front of that Grateful Dead PA even though I know it's 'all wrong' and would be completely blown out of the water by a modern line array. Anyone remember this Custom 8x15 bass cabinet - Amps and Cabs - Basschat Of course he chose speakers that would more or less work together, is that engineering? Who cares, it's a bit of fun, nobody here is going to buy the thing, but if we saw it in Metallica's back line???? Of course it's all wrong, those 8 speakers should be in a vertical line with proper crossovers and maybe in a D'Appolito alignment with the horns at ear level so the bassist can 'really' hear what they are playing. Think of this as like those giant figures on Route66 or the world's biggest pencil in the pencil museum in Keswick. If someone wants a custom 4x18 I'm up fr a commission

I can't resist these, as a retired science teacher i used to love the curve-balls the kids used to throw at me. Strings are going to deteriorate by chemical processes mainly oxidation but will also react with environmental substances of which I would think most will be coming from your fingers. There will also be a slow build up of dirt between the windings wich will affect the strings physically adding mass, affecting the flexibility of the strings and maybe adding some damping and lowering the Q of the string. Only the chemical processes will be affected by freezing the strings, if you don't play 'em they won't get mucky. Metals are extremely stable, any effect is likely to be extremely small. The chemical processes will go much faster if water is present so keeping them dry is crucial as you know. The chemical reactions take place when molecules collide and all molecules constantly move at any temperature above absolute zero. In fact they roughly double their movement for every 10 degree C rise. If you lower the temperature from room temperature to -10 in the freezer you will slow the chemical processes 30 degrees or by a factor of 8. If they are't in a sealed pack then condensation will build up on them and ice will form. IMO that would be worse than the gain in slowing chemical processes. The only way to test this of course would be to take a significant number of strings, store half in the freezer and the rest at room temperature and test them after a significant period of time. I've used string sets 6 years old and they've been fine so eight times that would be 48years later. As far as I know nobody has done this as a serious study. It might be possible to spot deterioration much earlier of course but I don't think it would show up as a change in the sound. Without a proper study the answer to your question is nobody knows. As a bass player rather than as scientist my answer would be that it probably isn't worth bothering. Within a couple of weeks of playing the deterioration of use is going to overtake any advantage you might gain. Set that against the unlikely probability of your freezer being a stable environment over many years and why bother. I certainly wouldn't put paper wrappings in the freezer over years and I'd expect plastic wrapping to become brittle and tear over time too. FWIW I use the previously mentioned Dean Markley Blue Steels which I buy in batches when they are cheaper. I store them in a cool dry cupboard and they last me about a year per set so i guess the oldest ones are 5 years old. As far as I can tell no deterioration at all happens over 5 years of storage. I've used 15 year old strings on my banjo (yes i know )and they have been fine too.

Don't dismiss the little mixer option. If space is limited then a bass combo isn't going to play the music well. A small PA speaker or two will sound pretty good with your bass and make the music sound good too. If you want bass amp sounds something like the Zoom B1four has good simulations of all sorts of amps and speakers. You can then choose deafening volumes if you don't want headphones.

Looks like I'm going to have to make some sawdust. My wife will be pleased.

The original cab was built just because I needed something I could build live for the bass bash. I used the Beyma SM212 because I had one laying around and because it is a decent driver. The main reason I went for a 30l cab is because I'd been gigging the original BassChat Mk1 design for a while and the extended bass was proving a problem in a lot of small venues. Not a problem with my Hartke where I could use the graphic but not good with other amps. I was regularly dialing down the response 10db at 50Hz and then adding something extra at 120Hz. I already knew that by putting the SM212 in a 30l cab I could engineer that response and have a smaller lighter cab. It worked better than I expected and it was a bit of a 'wow' moment when I played it at the end of the demo. It's been my go to speaker for pub gigs ever since. The B&C 12CL64 looks like an interesting speaker and I had considered it myself. It's engineered slightly differently from the Beymas with a lower excursion and higher efficiency. It has a lower thermal limit and that with the lower Xmax will mean less ability to handle deep bass. On the plus side it's a really affordable lightweight neo speaker. If you wanted to build something with it and share your build here then I'd be happy to do some modelling and design a cab for you. Welcome to BassChat

I allowed for the driver, the ports and a little left over for any bracing. you'll find that a similar amount is also allowed in the 50l enclosure

Just for interest these are the predicted responses of the two speakers at 320W, the thermal limit of the 12CMV2. You can see that the response below 100Hz is pretty nearly identical, above that the SM212 has about an extra db which is just about noticeable in A/B listening. Subjectively the volume levels are the same as the 12CMV2 has a broader midrange peak and of course that is where our hearing operates best. As i said above I think this is why it sounds more agile and detailed. The -10db point is around 50Hz which is quite good for a little cab like this and both speakers manage 120db levels across most of the range which was the original design target and should be enough to work for most bands.

Hmm could it be worse

I wonder if this was more to do with faint praise, you dissed his new love maybe. Tried her out and found the bass of his dreams somehow lacking?

Hi Dan, what do you like, the look or the sound? Changing speakers can be fraught. First of all the cab is or should be designed to work with specific speakers, changing for other speakers will probably change the bass response, if there is a severe mis match it will reduce the power handling from the listed power handling, in the worst case down to a few tens of watts and people have lost speakers because of this. I don't want to over- exaggerate though most speakers are similar but is is best to check than to find out the hard way. Secondly even if you get a match the frequency responses may be very different so the bass tone will change, it could be better or it could be worse but you won't know until after you've shelled out. Finally it's unlikely you'll save much weight the neo speakers will weigh a couple of kilos give or take so you'd be doing well to save more than 4-5kg that's a lot of wood you have there

Not really, cone area is related to dispersion and to efficiency. Like going into a pub and ordering on the basis of hop variety perhaps? Though in this case the radiating area is little different so it isn't going to be much of a factor.

UPDATE It looks like Beyma are about to pull the SM212. Coincidentally I've just been given a Beyma 12CMV2 (thanks to @Chienmortbb) to try in this cab, it has the same magnet but with a heavier cone, stiffer suspension and a new voice coil. It also has a pressed steel chassis and is considerably cheaper. The good news is that in this cab it actually sounds better. The bass response is basically unchanged, but one of the frequency anomalies of the SM212 has gone and there is a broad boost in output in the upper mids which makes the sound lighter and more detailed. I'm still investigating and haven't tried it at a gig for COVID reasons but I'm happy to recommend this speaker if anyone is thinking of a build. If I get more information I'll put it here.

Like everyone else I think you need to try them. Two eights have a slightly lower cone area than one 12 but not by much. The smaller speakers also mean they might beam the mids a bit less but we don't know the crossover frequencies for either cab so who knows. Their ads boast a lower frequency response for the 2x8's and the 2x8 is lighter but the 12 is advertised as noticeably louder by a couple of db's. the 2x8 looks an easier shape to carry on public transport. Only you can decide what is most important to you.

Just thought I'd finish off this little project. I left it with leads coming out of the port, good enough for testing and sitting in the corner but not very practical, not least because the mains switch was only available by reaching through the port. First thing I decided was to have the possibility of adding another 8ohm speaker, 20W would be better with an 8x10 Then I added a new switched IEC socket. I wanted to be able to remove my mods in the future so I wired up the IEC plug cut off from one of those Thomann euro plug jobbies This and the spade connectors can just be unplugged to return the amp to original. Bit of black paint and the job is done

ignore this

Hiya, well I'm having fun. Not least because your enthusiasm drove me to complete my own version of a baby combo. Fun playing it last night and I didn't wake the neighbours Don't worry about the 4ohm thing, it will give you an extra db but that's about it. You'll get around 10W into 8 ohms and if your amp uses the same chip as mine it will give roughly the same power into either impedance as it is current limited into lower impedance speakers. In any case the speaker you swapped to is * ohms and you know how loud that is. You lucked out with that port unless you did some calculations/mods as it is tuned almost exactly to the frequency I used in my modelling of your cab. If you swap to the Fane then a 4cm tube will lower the tuning of the cab to suit the new driver. I've assumed a port of 1.5mm wall thickness fitted inside the existing port with an internal diameter of 40mm. Your maximum sound output is going to be around 105dB, 106 in the midrange and 104 in the bass.

Well done, I was looking at one of those little amp modules myself to beef up my lockdown combo. I was looking to cheat even more and use one of the ready made pre-amps. Following with interest.

Is it hypercardioid though? If it is picking up sounds from all around then it's omnidirectional by definition. There is no strict definition of what cardioid, super-cardioid and hyper-cardiod means anyway and my experience is that the actual directional nature of mics described as cardioid varies a lot. If it's part of a cheap set shipped out of China quality control can be problematic and who knows what capsule is inside. It's also possible that part of the mic is broken, directionality is achieved by cancellation. The omni directional part of the mic is joined with a bidirectional signal and the sound from behind in the bidirectional element cancels the rear sound from the omni part. If the capsule is broken or blocked by damage/poor manufacture then the cancellation won't happen. You can test the directionality by talking your way around the mic and checking the sound level falls off at the sides of the mic.

so this is what effect the extra 2litres make. I've tuned the cabs a little lower to give the nearest to flat response you can get with these speakers and the extra cab volume does give more flexibility. I don't mind a coloured cab but for me that peak is a little too big and a little too high with the current speaker. Actually the volume change has moved the peak and the -3db point down roughly 10Hz which is quite nice. The Fane will give quite a grown up tone for such a small speaker, a 4x6 might be quite interesting. However if sheer volume is the thing then there is no point in changing. If you send me the port dimensions Michael I can optimise them for you.

Hi, I've just run some modelling but this is based on the 9l volume of my cab. The Fane I mentioned and used myself comes out better slightly than the Beyma so if you want to go ahead I'd buy that. The blue is your current speaker in a ported cab and the purple is the same speaker in a sealed cab of the same volume. as you can see they all meet at the higher frequencies but low down the ported cab gives a lot more bass than the sealed cab down to about 70Hz where they cross over. As you can see there is a huge +4dB peak at around 160Hz in the low mids. Your speaker is underdamped (Americans use this term differently I think) and normally this much of a hump would be undesirable distortion. In practice this will be extra volume and a warmer sound which might be the fun factor you like about the way it is set up at the moment. Your speaker models better in a much larger sealed box, you can see the sealed box response is flatter but rolling off at 200Hz isn't any good for a bass player. For comparison the green response is the Fane, as you can see the volume peak is lower, just under 2db, and at a lower frequency around 110Hz, quite a good place to have a peak for a bass especially if it is bass light. there is also an extra 2db of bass below this point. All this means is that you have struck lucky with the speaker you have in terms of volume, that huge hump is giving you a lot of extra sound in the low mids. The other speakers will be subjectively quieter. In terms of sound quality the Fane will sound better for bass guitar. It has a flatter response and a touch more deep bass below 100Hz, the 2db boost at 110Hz is well controlled and in a nice place to give a subjective impression of real bass. All this is in a 9litre box yours may be a bit different.

OK it looks like we have a fun lockdown project to find how far the envelope can be pushed. Having had a lot of fun with my version I've ended up with a usable practice amp in a tiny practical box with very little effort. Actually it's better than that; it's good enough that I can get enough volume from my electric bass to do what other people do with double bass, play with other acoustic instruments and singers. That Beyma is just slightly better than the Fane 6-100 that I used too. I had the Fane kicking around from another project so I didn't have to spend anything which was a bonus but £33 for a weekends entertainment and the possibility of something satisfying to play with your family sounds like it's worth a try.

It's an OK speaker but designed for car use, the specs are bit dubious as they quote sensitivity as both 98dB which is high and 91.5 in the T/S parameters which is what you'd expect from this sort of unit. It probably has higher output at higher frequencies which is where they get the 98db figure from. They quote Fo as 114Hz which is well above bottom E at 41Hz so this is going to be well down on bass output but as Bill says it's not all that bad. You aren't going to get something that matches your double bass in terms of volume out of a 15W amp in a small box like this. You could get a little more output and slightly better bass response out of the Beyma I linked you to. The beyma would be suitable for a ported cab which would also help a little. None of this is going to be dramatic though. I think at this point you need to decide if you are driven enough by curiosity and the need for a project to want to see how good this little amp can be and then decide if £33 is worth it to satisfy the question. This is a bit like adding a second carburetor to a Morris Minor, it will go faster but it'll still be a Morris Minor