stevie

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.

[quote name='zero9' post='929731' date='Aug 19 2010, 01:11 PM']Check out Phil Jones' article here:[/quote] Why? There's no mention of Speakons in there.

[quote name='johnny_frog' post='929479' date='Aug 19 2010, 10:25 AM']Yup... good book... even i could follow it[/quote] On the other hand, I found it completely useless.

[quote name='MB1' post='926621' date='Aug 16 2010, 04:13 PM']MB1. ...Hes got 1083...100% Positive Feedback.. ..The Plop Thickens![/quote] Mmmm. I wonder if I misread his feedback rating..... Over a thousand feedbacks without a single negative is pretty impressive.

Interesting one. Zero feedback and the expression "it could be a fuse" is suspicious though. ("I'm too stupid to change a fuse or ask somebody with an IQ over 100 how to do it"). My guess is he's had a quote for the repair and it would cost more than the amp's worth.

Such a shock - Old Git seemed like a permanent fixture on Basschat. I never met him but always enjoyed reading his posts, which were many and varied and always interesting. So sad. He's going to be missed around here.