Chienmortbb

It is a thing but only in big venues with flown line arrays.IMHO

I have been looking at those. More later.

No but it is a good point. Smoke (without fire or exploding semiconductors) is often used to check airflow in various industries.

This is taken from my build diary and posted earlier today. I post it again here as I think it is relevant. "I have done some experimentation myself with fans and the noise. .............. turbulence caused by the fan is what helps the cooling. Of course, turbulence means noise BUT I found that most of the noise is caused by vibration. Sadly the metal used on most amps is a great sounding board and makes the noise problem worse. I have managed to reduce the noise on fans on some amps using rubber mountings from AKASA and you can get low noise fans from companies such as Noctua. The Noctua Fans are well made but to get the lowest noise you have to use an adapter that reduces the speed, probably by reducing the voltage applied to the fan. Noctua do take care to reduce vibrational noise as far as possible but you pay for this extra and the fancy packaging." In short there is no such thing as a silent fan but by selecting the airflow/voltage carefully and reducing the vibration transferred to the chassis you can reduce noise a lot. Also two low spead fans may be better than on fast fan but surely the old Stage/Studio switch that simply switched the fan off could work well?

To be fair outsourcing repairs is not new and need not be a bad thing as long as the company are well trained. My old company, Panasonic, outsourced some product ranges to a company started by two ex-Panasonic Service Engineers, Multicare. They are now doing repairs for many companies including JBL, and also take in consumer repairs.

There are issues with the enclosure I am using with regard to heat dissipation. If you look at the side panels, you will see that the extrusions are horizontal rather than vertical and I don't want to put fans on the outside. So fans must be inside but inside the panels and heatslugs of the amp modules are smooth. The question is, do I attach heatsinks inside to create something that a fan can work on, or would a fan just blowing air through the case help? Rod's article suggests not. Extra heatsinking will add weight and although the whole thing is not heavy, the enclosure alone already weighs 2Kg.It also does need a small amount of extra circuitry to drive the fans so I have to decide whether the extra weight and mechanical and electrical complexity are worth it.

To explain a bit more. These old Ramsa WS-A80 speakers are passive and rated at 80 watts RMS but are 20 years or more old. They were conservatively rated. However the amps are capable of well over 300 watts into 8 ohms. So I had to be careful. Add the fact that I was in a shed and that I value my ears... So the A input was fed from the Main L output from my mixer and the B input was fed from the R output of my mixer. Despite the outside temperature being close to 30 degrees C, after half an hour the sides of the amp case were only warm to the touch. I will do some proper temperature measurements soon but as a rule of thumb, 30-40 degrees is warm 50-60 is hot but 60 is just about OK to touch without burning. 70 degrees is too hot to keep your fingers on. Based on this, I guess the temperature was under 40 degrees. A word about fans. Many bassists hate fans but there are pros and cons. According to Rod Elliott of the Audio Pages https://www.sound-au.com/heatsinks.htm#s18 fans have to blow not suck. Section 18 of the article details Rod's conclusions on fans. I must admit that I cannot find the source but I have it in my mind that a fan cooled heatsink can remove 4 times as much heat as one passively cooled just by a heatsink if placed correctly in relation to the heatsink, I have done some experimentation myself with fans and the noise. Again if you read Rod Elliott's article, he says that the turbulence caused by the fan is what helps the cooling. Of cause turbulence means noise BUT I found that most of the noise is caused by vibration. Sadly the metal used on most amps is a great sounding board and makes the noise problem worse. I have managed to reduce the noise on fans on some amps using rubber mountings from AKASA and you can get low noise fans from companies such as Noctua. The Noctua Fans are well made but to get the lowest noise you have to use an adapter that reduces the speed, probably by reducing the voltage applied to the fan. Ho Noctua do take care to reduce vibrational noise as far as possible but you pay for this extra and the fancy packaging. I have tried Gelid low noise fans and found that apart from the white fan blades, they give no advantage over traditional fans. To reduce noise you have to have rubber mountings and/or run the fans at a lower voltage and hence a lower speed. This of course reduces the cooling efficiency of the fan.

Do you mean my last post or all of it?

Yes I could have used either method but as the modules have a balanced input, I was going to just reverse the XLR hot and cold cable on the B channel via the slide switch.

There is a blog called the slow diyer where a chap up north (Scandinavia not Hotton) tells the story of his slow audio builds. Compared to me he is a formula one car, however: I tested the Kilowatt today with speakers and music. It is quite impressive with the 8" Ramsa cabinets I keep at home. I have to be careful as they are only rated at 80 watts RMS although I suspect Ramsa were a little more conservative with their ratings that most modern speaker companies. I only had it wired as a stereo amp but it gives me confidence to go forward with it. It seems to run quite cool, it was warm but no more than that. What most people forget is that the heat from a class D amp does not change too much as the power goes up and with the ambient temp so high it was a fair test. That being said, I will fit temperature controlled fans as the amps have a linear voltage output that corresponds to the heatsink temperature. That makes it easy to add fan cooling. I now need to work out the best place for the fans. The noise is not an issue as the amp is for PA use not as a bass amp (if you see a bass pre-amp wanted ad tell the mods and get me banned) but the fans will only come on if the amp is hot and they will be run at lower voltages than specified so the noise should be minimal. Next is to finish the front panel (escutcheon) design and get it made. I am getting it made without anodizing as it is cheaper and I may well change the design later. I also need to build the auxiliary power regulators for the level meters and DSP.

The Laney's seem pretty good for the money. They are a bit old school, class A/B amp with a transformer power supply but still under 17Kg. The handles are excellent, with the top handle for carrying in and the side handle for lifting onto a pole. Despite being a weedy 70year old I can lift them with ease. The angles are good for floor monitors too. No DSP so what you put in is what comes out. I have yet to put them to use in the band situation. Hoping to do that on Friday.

Could be a nice haul but unlikely to be suitable for modern bass cabinets. That being said, I would take a punt if I were near enough.

It's OK now, Boris has gone (nearly) so we might rejoin next week 😁

That ain't a Ric its a Danelectro Longhorn.

Very few in the UK.

The dreaded white gloop. it is a type of caulk or sealant that is used to stop large components moving. If they move during transport, they will eventually cause a dry joint, causing a fault.

True bypass was/is one of those guitarist fads, someone came up wit the idea that lots of pedals with buffers was a bad idea so pushed the idea of true bypass where the input is directer connected to the output of a pedal when the effect is OFF. It is one of those ideas that has a grain of truth in that multiple pedals concatenated = multiple noise generators. However all you favorite BOSS pedals were/are buffered and a well designed buffer (its not hard to design a good one) will not affect your sound and you need buffer at some stage especially the end of the chain.

I have one of those too but it does have a baked in mid scoop.

Probably lose a lot of girlfriends too.

There is a joke that the Secret Service often use a bass solo as an interrogation technique as everyone talks though a bass solo. Its funny because its true. The player I most admire is probably Glenn Hughes not only a great bass player but one of the best bass playing singers. However for the way he weaves a bass line into a song it would have to be Jack Casady. Seem here at 69 and still struttin his stuff (1min 10secs)

The first several batches and revisions. Admittedly they were long since sorted.

Absolute Music in Bournemouth usually have a good selection although a long trek from home for you. . https://www.absolutemusic.co.uk/search.php?search_query=precision+bass&section=content Just ring ahead to make sure they are on demo. They will get them out of the warehouse if you ask.

That is Active. The clue is the 48V phantom power.

Andy every bass and guitar I have owned would have been better with inserts and machine screws.

It is best not to assume anything about amps or cabs in my experience.