stevie

I got to the root of the problem. There was a very slight gap between the fan and the case, which caused the fan to rattle against the case. It actually sounded like the fan was buzzing and rattling but it was in fact the casing creating the racket. The metal case is also screwed very firmly to the MDF outer sleeve, which makes the vibrating area even greater. The only reason I discovered this was because Dave had supplied me with some silicon spacers for the fan. When I fitted them the racket subsided considerable, although I still had to use some thin foam to space the fan completely off the chassis - and that did the trick. Clamping the fan firmly to the chassis helped a bit, but not much - and certainly nowhere near as much as spacing the fan away from the metal casing. I ended up fitting a 2,600 rpm Papst that generates about the same amount of 'wind' as the original. All I can hear is the whoosh of air now. It's not quiet, but it's not an annoying noise like before. With a better design of case (i.e. a proper air inlet), I'm sure a 'silent' fan type would be fine.

If you can read at a reasonable level, you can pick the midi files off the internet, print out the bass lines and learn 8 songs of average difficulty in a couple of hours with the help of a midi player. You might not be able to memorize them in that time, but you can always take the dots with you to the audition. This doesn't answer your question, but my answer to your actual question would be 'it depends'.

[quote name='Chopthebass' post='952157' date='Sep 10 2010, 07:10 PM']What was the technical bollock he dropped? I watched part of the vid and most of the cabs sounded the same through my headphones![/quote] It would be interesting to know if anyone else noticed :-) It's not very far in. You could hear the differences between the cabs quite clearly on good phones but I wouldn't say the differences were earth shattering. The clarity and lack of colouration was impressive. Boogie has tended to go for high quality drivers in the past - and use 3/4" birch ply. Which is a recipe for a good box.

That's interesting - and very well done. I particularly liked it when the smooth-talking sales guy dropped a complete technical bollock which showed that he had no idea what he was talking about. That said, all the cabs sounded really good. I wonder who is supplying the neo drivers.

That's nothing! I'm working on a job that involves a car whose tyres cost $25,000 a set. And there's more.... To actually get the tyres changed, you have to send the car back to France, where they charge you $70,000 for the privilege. The world has gone mad I tell you! Makes Fodera sound quite reasonable actually

[quote name='flyfisher' post='948615' date='Sep 7 2010, 06:34 PM']I've often wondered why so-called 'top-end' gear is so highly priced. Do they really use more and/or highly priced components or is the high price just a reflection of the low production volumes? Or, more controversially perhaps, are they just adding sky-high margins because they can get away with it?[/quote] It has to be highly priced because otherwise it wouldn't be top-end. In the higher echelons, perceived value is more important than actual value. So, your third suggestion is more accurate than you might imagine.

[quote name='krispn' post='948106' date='Sep 7 2010, 11:06 AM']- smaller fans = less noise too right?[/quote] Exactly the opposite in fact. Fan speed is what causes noise. The slower the fan, the lower the noise. A large fan moving slowly will shift as much air as a small fan moving quickly but be quieter (less turbulence). That's why PC makers have moved from 80mm to 120mm fans.

This is the first amp I've had with a fan. I previously had a passively cooled power amp with a separate preamp, and before that, a Trace 200-watt head, which was passively cooled. I don't mind a quiet whoosh, but I can't stand this rattly buzzing.

[quote name='lojo' post='947543' date='Sep 6 2010, 07:28 PM']bet that puts out ![/quote] You mean it gives blow jobs too?

Ghost, it's the HA300/7 built around 1990. I could post some pictures but the cooling arrangement and the power amp section are exactly the same as on the pictures you posted earlier. I don't really need a replacement OEM fan, as the ones I'm using are better quality than the original. I'll do some more experimenting tomorrow to try to get to the bottom of the noise problem.

[quote name='Colledge' post='944125' date='Sep 3 2010, 01:15 AM']i think the cooling system must work well enough because my amp has never felt hot after running at almost full tilt. ive even ran the head without a case and the heat sinks are just about warm to the touch after being run at a decent volume for about half an hour, they must have done something right.[/quote] It does sound like the amp only needs minimal airflow to keep the heatsink cool, which is good news.

I fitted another Papst into the Trace. This one runs at around 2500rpm (slower than the original Trace one), but it was still loud. I then turned the fan round to blow air out of the back of the amp and taped over the vents. This caused the volume of air expelled by the fan to drop by around 75%. It's a fair assumption that air intake is being restricted by the lack of vent holes at the front, as some of you surmised. As it is, however, the fan is not moving enough air and is probably being placed under undue stress. Without any way of increasing the vent area at the front of the case, this configuration is a bit risky and I wouldn't recommend it. Worth a try though. I've now installed a 1600 rpm Papst in the amp (blowing into the amp, as per the original Trace design). This is considered to be the quietest computer case fan in existence - inaudible from a distance 1 metre - yet installed in the Trace, it is still annoying loud. I'm hearing mechanical noises rather than wind noise and these are being transmitted through the wooden case. So, the next task is to install the rubber grommets Dave so kindly supplied (Thanks Dave!!). I'll report back. If there are any fan experts here, I'd be happy to hear from them. And before anyone mentions it, no I'm not being fussy. I work about 1 metre away from my PC which has two fans blowing out the back. My single fan in the Trace head sounds *much* louder.

Some excellent info - thanks, everyone. I'm going to go ahead and mod it. I don't need to buy the fan, as I have a few different ones in my workshop. The quiet Papst one works at 1600rpm, which should be OK - as long as there are enough holes in the front to allow it to work, as SP said. Dave, I'd appreciate a set of those rubber mountings. There does seem to be quite a bit of noise being transmitted from the fan housing to the case. Should anyone wish to follow my example, I'll post the results on here.

Ghost, mine is the same as or very similar to yours. Most of the exhaust air comes out right next to the fan, with a bit coming out through the graphic equalizer slots. I've no doubt it works, but it strikes me as extremely inefficient because the fan should really be pulling fresh, cold air through the case, across the heat sink and then out the opposite side. I really do need to put a quieter fan in, and rearranging the cooling arrangement seems like an obvious thing to do at the same time. I'm just wondering if I'm missing something, as it seems unlikely that Trace would do this without some kind of reason, although I have to admit, it sure looks like a major design booboo from here.

I am enjoying my recently acquired AH300/7 but found the fan noise a little too loud. So I swapped it for a Papst of similar rating (same power consumption). Unfortunately, the Papst must be more efficient than the OEM fan because it's faster and therefore even louder. I now want to change it for a lower speed Papst, which I know will be quiet. However,.... Trace have designed the fan cooling on this amp in a most curious way. The fan sucks in from the outside (at the back) and blows air directly onto the heat sink inside. Not what I would do, but it obviously works. At either side of the fan are two large vents, which create an efficient open circuit for the cooling system: the warm air is blown out of the case right next to the fan, where it is sucked in again to be recirculated. Is this normal? It strikes me as being absolutely bl**dy stupid. I'm thinking of blocking the vents with tape and reversing the polarity of the fan so that it will vent to the outside of the case. As I'll be using a lower speed fan than standard, I'd be interested to know what you think.

[quote name='btp' post='939735' date='Aug 30 2010, 01:47 AM']1) Replace that one Celestion driver, and live with the frequency response issue?[/quote] That's the obvious, easiest and cheapest option. [quote name='btp' post='939735' date='Aug 30 2010, 01:47 AM']2) Replace both Celestions with some other driver (neo preferred, but doesn't have to be...), in the hopes of extending the frequency response?[/quote] Assuming the cab is already on the floor, the easiest way of extending the bass response is to use your tone controls. The only other way is of getting more bottom end out of the cabinet is to use lower sensitivity bass drivers, which in practical terms amounts to the same thing. If you do that, however, the mid and HF will then be unbalanced. It's not a good idea. [quote name='btp' post='939735' date='Aug 30 2010, 01:47 AM']3) Do something entirely different that I haven't imagined yet...?[/quote] If you think you are overpowering the bottom end of your existing cabinet (which might explain the damaged driver), it could be that you need another cabinet to support the bottom end when you are playing at volume.

Most of those things are possible, but the first thing to check is that both cabinets are in phase. Connect a 9V battery to each cab and watch which way the cones move. They should both move in the same direction (preferably forward) when you connect the + on your battery to the + on the lead to each cab. Sorry if that's obvious, but there's no point going any further unless you've done that.

Nobody's mentioned the fact that the plugs are solderless. That's a plus point. You just strip the end of your cable, insert it into the plug and tighten a grub screw with an allen key.

A shock in transit could have shifted the magnet slightly, which would cause the coil to seize. It's not normally worth repairing that kind of fault, as it's a lot of work. If it were mine, I'd report the fault to my seller asap and ask for a refund.

Have you seen the thread on bassists who play like guitarists?

[quote name='medders' post='931285' date='Aug 20 2010, 07:45 PM']Anyone care to enlighten me what each of the five knobs on the 1200S actually do? Yes yes I know it sounds daft but I really want to know the exact details.[/quote] I thought the 1200S only had two knobs. I have an 1100S with five knobs. If yours is like that, the top two knobs are volume and tone. The latter only works in passive mode. The bottom three knobs are bass mid and treble and these work only in active mode. There are two switches. The two-way switch switches between active and passive. The three-way switch switches between neck/neck + bridge/bridge pickups.

[quote name='Clarky' post='929540' date='Aug 19 2010, 11:04 AM']Perhaps you would like to offer an alternative learning resource suggestion to lysdexia?[/quote] If I thought there was an outstanding one, I'd gladly mention it, Clarky, but most beginner books are just plain awful. The only one I can wholeheartedly recommend is out of print and requires that you to read standard notation - not what most people want. I can, however, recommend Ed Friedland's Blues Bass book. It's excellent, inexpensive and suitable for a relative beginner. As long as he wants to play the blues, that is.

There are more than you think. A large number of players, who are clearly highly skilled, sound like failed classical guitarists to me. You know the ones. They think Paul McCartney can't play but sound like a bad imitation of Julian Bream with his hands tied behind his back.