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Cursitor Doom <curd@notformail.com>: Jul 26 12:55PM Hi all,   I have an Audiolab 8000 amplifier I picked up at a boot sale and would like to establish what it's capable of, since subjectively the power output seems a bit on the low side when driving recommended speaker loads. Anyway, ideally I'd like to use an 8 ohm 100W power resistor as a dummy load for each channel and then measure the p-p voltage output across it on a scope with the amp turned right up. Trouble is, I don't have such a resistor and was wondering if there's any suitable substitute? I recall someone somewhere using a car headlamp bulb but I doubt they come as 8 ohm units so some sort of elaborate series/parallel combo of lamps would be necessary to get that value. Has anyone a better idea? cheers, CD.

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 02:04PM +0100 "Cursitor Doom" wrote in message news:mp2lbl$9no$2@dont-email.me...   Hi all,   I have an Audiolab 8000 amplifier I picked up at a boot sale and would like to establish what it's capable of, since subjectively the power output seems a bit on the low side when driving recommended speaker loads. Anyway, ideally I'd like to use an 8 ohm 100W power resistor as a dummy load for each channel and then measure the p-p voltage output across it on a scope with the amp turned right up. Trouble is, I don't have such a resistor and was wondering if there's any suitable substitute? I recall someone somewhere using a car headlamp bulb but I doubt they come as 8 ohm units so some sort of elaborate series/parallel combo of lamps would be necessary to get that value. Has anyone a better idea? cheers, CD.           An electric fire/heater element works well.       Gareth.

N_Cook <diverse@tcp.co.uk>: Jul 26 03:12PM +0100 On 26/07/2015 13:55, Cursitor Doom wrote: > ohm units so some sort of elaborate series/parallel combo of lamps would > be necessary to get that value. Has anyone a better idea? > cheers, CD.   I use a bank of 10 vitreous resistors spaced apart on tag board with a 60V sub 1W bulb across (for any DC problems etc) and a well droppered small low-wattage monitor speaker (for sound quality monitoring)

MJC <gravity@mjcoon.plus.com>: Jul 26 04:17PM +0100 In article <ZV4tx.58349$Ch1.13405@fx40.am4>, sound.service@btconnect.com says...   > An electric fire/heater element works well.   I guess a 1kW unit for 110V would need ca 10A and hence be ca 10 ohm; not far off. But a 230V element would have higher resistance and several in parallel might be needed for each channel for a 8 ohm load...   Mike (retiring exhausted after all that mental arithmetic!).

"Ralph Mowery" <rmowery28146@earthlink.net>: Jul 26 11:43AM -0400 "Cursitor Doom" <curd@notformail.com> wrote in message news:mp2lbl$9no$2@dont-email.me... > ohm units so some sort of elaborate series/parallel combo of lamps would > be necessary to get that value. Has anyone a better idea? > cheers, CD.   The headlight will not have enough wattage for that amp. A 100 watt light bulb may seem like a good subistute. Only problem is the resistance changes with 'brightness' of the bulb. When dark the resistance is very low and gets higher as the bulb lights up. Every time the power changes, the resistance of the bulb will change due to the heating of the filiment.

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 04:46PM +0100 "MJC" wrote in message news:MPG.301f0a76649358d3989683@news.plus.net...   In article <ZV4tx.58349$Ch1.13405@fx40.am4>, sound.service@btconnect.com says...   > An electric fire/heater element works well.   I guess a 1kW unit for 110V would need ca 10A and hence be ca 10 ohm; not far off. But a 230V element would have higher resistance and several in parallel might be needed for each channel for a 8 ohm load...   Mike (retiring exhausted after all that mental arithmetic!).             These are really cheap: http://www.amazon.co.uk/2Kw-Electric-Heater-Overheat-Protection/dp/B004KDRCUO/ref=sr_1_2?ie=UTF8&qid=1437924981&sr=8-2&keywords=electric+fan+heater     The heater element in the one I bought was actually several windings, and easy to hack and series/parallel/tap etc to get the right ohmage.   I had hoped to use the built in fan to cool the element, but it turned out the fan motor was actually 110v, and took this from half the 240v heater element. Doh! So I bought another one which sits on top blowing cold air over the elements when required.   (It should be noted that the resistance of the element is not constant, it increases somewhat with temperature, but I don't need an accurate fixed resistance load for my purposes)           Gareth.

N_Cook <diverse@tcp.co.uk>: Jul 26 05:01PM +0100 If you stick to 400Hz sine ,and a constant resistance, for general power monitoring purposes , a good quality DVM on the AC scale gives a good RMS reading. I only use a scope if there is quality of sound issues

Jeff Liebermann <jeffl@cruzio.com>: Jul 26 09:19AM -0700 On Sun, 26 Jul 2015 12:55:17 +0000 (UTC), Cursitor Doom >someone somewhere using a car headlamp bulb but I doubt they come as 8 >ohm units so some sort of elaborate series/parallel combo of lamps would >be necessary to get that value. Has anyone a better idea?   Have you searched the web for an 8 ohm dummy load? <https://www.google.com/search?q=audio+8+ohm+dummy+load> <http://www.ebay.com/itm/like/201057901616> Note that the resistors should be bolted to the biggest aluminum heat sink you can find. Mine lives at a local auditorium and weighs about 20 Kg. It doesn't need to be that heavy to handle the heat, but heavy does tend to discourage those that would want to walk away with my dummy load. My collection of phosphorescent test cables lasted about a week. <http://www.homedepot.com/p/Rust-Oleum-Specialty-10-oz-Glow-in-the-Dark-Spray-267026/204209388>   Also, this load consists of 4ea 8 ohm resistors in series parallel. That was suppose to be useful to produce a 2 to 32 ohm load, for stereo or mono, none of which I've ever needed. It also had a pair of meters across the loads, but one of the stage gorillas stepped on one and I've never bothered to replace it for lack of a matched pair.   Hint: Leave room for one or two thermometers, which will help you determine when it's safe to handle.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 05:23PM +0100 "Cursitor Doom" wrote in message news:mp2lbl$9no$2@dont-email.me...   Hi all,   I have an Audiolab 8000 amplifier I picked up at a boot sale and would like to establish what it's capable of, since subjectively the power output seems a bit on the low side when driving recommended speaker loads. Anyway, ideally I'd like to use an 8 ohm 100W power resistor as a dummy load for each channel and then measure the p-p voltage output across it on a scope with the amp turned right up. Trouble is, I don't have such a resistor and was wondering if there's any suitable substitute? I recall someone somewhere using a car headlamp bulb but I doubt they come as 8 ohm units so some sort of elaborate series/parallel combo of lamps would be necessary to get that value. Has anyone a better idea? cheers, CD.         Here's another idea: Get a reel of this - http://uk.farnell.com/pro-power/ecw0-80/wire-0-8mm-copper-enamelled-125m/dp/1230984   By my calculations it will have a resistance of 4.25 ohms. (117m of the 125m length gets you 4 ohms) Although it is only rated at 0.8A, I reckon you could extend that massively by unravelling it all and laying it in a large container of water. You could even have a flow of water through the container to keep the temperature down.   It would be interesting to find out what power rating this could actually tolerate.   Or is this a really stupid idea?! (For some reason this amuses me)       Gareth.

Peter Easthope <petereasthope@gmail.com>: Jul 26 08:42AM -0700 Can anyone explain how a computer serial port is disabled and enabled? Many Web pages cover the software topics but I've found nothing explaining how a BIOS disables a port. Is is done by clearing any interrupt assignment to the port? Is the power to the UART shut off? Other ways? Probably more than one technique has been used but not a large number.   Can anyone cite a Web page which answers this?   Thanks, ... Peter E.

jurb6006@gmail.com: Jul 25 11:32PM -0700 Sounds like the best bet might be to ask the vendor of the equipment you already have. It will probably just fit right in.   Unless I am misunderstanding this.

avagadro7@gmail.com: Jul 26 07:28AM -0700 > Sounds like the best bet might be to ask the vendor of the equipment you already have. It will probably just fit right in.   > Unless I am misunderstanding this.   ////////////////////////   no, the question is geek simple....your answer was the vendors answer   digital output to digital input....but that's not what happens as we have read mnay tmeis wthi thoer equimmmmmm ...

N_Cook <diverse@tcp.co.uk>: Jul 26 10:17AM +0100 Not got inside yet and before doing so, less I disturb something. Inserting a mono jack in one of the input channel I/O Insert sockets, kills throughput to phones and also amp hiss at the phones output. The PMP1280 SM ,out there, does not seem to have a control line attached to the I/O insert socket switches at all , so different there , unless there is some sort of auto lack-of-signal mute circuit somewhere. At the moment I wanted to rule out something silly in the way of a wrong switch setting combination or something. The user manual shows nothing that could cause this.

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 11:06AM +0100 The Insert socket is a normally closed switched stereo socket between the Mic and Line amplifier and the rest of the channel circuitry. The Tip is the Send, the Ring is the Return. So inserting a mono jack will just disconnect the mic and line amp signal from the rest of the channel, and short out the input (Return) to the rest of the channel. Effectively, all you are doing is shorting the signal going to the EQ section and beyond. There should be no interaction with any other part of the desk, and no need for any, I have never heard of any Insert being anything other than just an inline send and return.   The only thing you should notice is that any noise from the Mic/Line amp in that channel will be effectively muted.     Gareth.           "N_Cook" wrote in message news:mp28he$4k1$1@dont-email.me...   Not got inside yet and before doing so, less I disturb something. Inserting a mono jack in one of the input channel I/O Insert sockets, kills throughput to phones and also amp hiss at the phones output. The PMP1280 SM ,out there, does not seem to have a control line attached to the I/O insert socket switches at all , so different there , unless there is some sort of auto lack-of-signal mute circuit somewhere. At the moment I wanted to rule out something silly in the way of a wrong switch setting combination or something. The user manual shows nothing that could cause this.

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 11:07AM +0100 Oops, excuse the top posting, don't know how that happened!     Gareth.

N_Cook <diverse@tcp.co.uk>: Jul 26 12:00PM +0100 On 26/07/2015 11:06, Gareth Magennis wrote: > moment I wanted to rule out something silly in the way of a wrong switch > setting combination or something. The user manual shows nothing that > could cause this.   So normal action. If you plug a guitar , so mono jack, in those I/O sockets then no guitar throughput, but other channels should be normal . I'll try signals in 2 channels, different socket classifications, before opening up. It all seems a bit odd having a 1/4 inch socket, per channel marked Line/Mic and not instrument, and the other one I/O , plus XLR for mic

"Gareth Magennis" <sound.service@btconnect.com>: Jul 26 12:51PM +0100 "N_Cook" wrote in message news:mp2ei9$mqk$1@dont-email.me...   On 26/07/2015 11:06, Gareth Magennis wrote: > moment I wanted to rule out something silly in the way of a wrong switch > setting combination or something. The user manual shows nothing that > could cause this.   So normal action. If you plug a guitar , so mono jack, in those I/O sockets then no guitar throughput, but other channels should be normal . I'll try signals in 2 channels, different socket classifications, before opening up. It all seems a bit odd having a 1/4 inch socket, per channel marked Line/Mic and not instrument, and the other one I/O , plus XLR for mic           Yes, a mono jack into the Insert socket will produce no sound whatsoever, it is not an input socket.   However, if you plug a mono jack in part way, so the plug tip makes contact with the socket's ring connector, you CAN often inject a signal into the channel. However, this part of the circuitry is at line level, so a guitar is very unlikely to have enough output for this method to be useful. You'd stand a better chance using the proper line input socket and the gain control, or possibly the Mic amp with a suitable adaptor cable, or better still use a DI box, that's what they are for.     Interestingly, the Power Amp Insert sockets are wired the other way - tip is return and ring is send - so plugging a mono jack in these WILL overide the mixers output and make sound.         Gareth.

avagadro7@gmail.com: Jul 25 12:53PM -0700 GLASS ! always enjoyed Glass....and Glassman.   I use EC as a general contact cleaner...if not then thinner then EC. EC replaced CHOH except for tanking parts.   I missed the 'percent volatile'   I set the van's 5.4 right bank on fire testing with 1948 methods n not reading the manual.   There's an AP halon extinguisher just inside the cargo door.....   the loom's wire wrap didnah suffer damages.

Phil Allison <pallison49@gmail.com>: Jul 25 06:19PM -0700 Jeff Liebermann wrote:     > <http://www.crcindustries.com/faxdocs/msds/5101.pdf>   > Looks like a mix of naphtha, difluoroethane, hexane, dimethylbutane, > methylpentane.     ** Naptha (70-80%) is similar to petrol and is the main solvent, as used in products like WD40.   Difluoroethene (20-30%) is the propellant, a gas at room temp it is also used alone cans of "air duster".   The last two are in very small amounts, so likely just common contaminants of the others.   .... Phil

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