I am gald you talk about ILP. We had various modules one could buy like Sinclair, Tuac, and many too awful to repeat. ILP was a very serrious attempt to make something fool proof and almost excellent. Given the super low cost and ease of use they could not be bettered.
The Sinclair was worst of all and best of all. It had the first use I can think of in mass production of an op amp style power amp. The output devices were really driver transistors. That made them super fast and super fragile. None the less it could put to shame many designs and was the basis of the A&R A60 which was supurbly robust and good sounding. The ILP was by the standards of the day excellent. Sadly the need to sell it cheaply seemed to take it from being top of the tree. JLH kit amps were that.
The Sinclair was worst of all and best of all. It had the first use I can think of in mass production of an op amp style power amp. The output devices were really driver transistors. That made them super fast and super fragile. None the less it could put to shame many designs and was the basis of the A&R A60 which was supurbly robust and good sounding. The ILP was by the standards of the day excellent. Sadly the need to sell it cheaply seemed to take it from being top of the tree. JLH kit amps were that.
I forgot to say. Tuac was a throw back to a time that hardly existed. As I never saw the circuit I have to guess a pumped up transistor radio circuit with driver transformer. I would think they aimed to be 1% THD. However a very good amp the Rogers was not so different and was genuine hi fi. I could imagine if done with care an amp like that still might make friends. In valves it would. OEP make low cost items that could do the job for telecoms I suspect. I have used a few ILP modules in my time. A few failed due to me asking too much.
My friend John remembers building an ILP into a big PA unit one afternoon. It was a get us out of trouble amp in the spare space. It got used a lot for things that didn't matter too much or for some reason they had forgotten to pack a unit. Apparently it always worked and was well liked. Often very dusty as it was use then forget. The idea was to be able to be fixed quickly and have utility. He went on the make SSL mixing desks. SSL being the major user of NE5532/34 at the time and he thinks caused the price to lower. John thinks more than 1 000 000 used a year at one time. Not a man to like something for no good reason.
My friend John remembers building an ILP into a big PA unit one afternoon. It was a get us out of trouble amp in the spare space. It got used a lot for things that didn't matter too much or for some reason they had forgotten to pack a unit. Apparently it always worked and was well liked. Often very dusty as it was use then forget. The idea was to be able to be fixed quickly and have utility. He went on the make SSL mixing desks. SSL being the major user of NE5532/34 at the time and he thinks caused the price to lower. John thinks more than 1 000 000 used a year at one time. Not a man to like something for no good reason.
Hi Everyone, I found the entire DIY Audio site by looking for details/data sheets I’d lost on my MOS248 modules!
I found them here - so thank you.
I built two monobloc power amps in 1982 using the MOS248 modules and these were later housed in the same case - although remaining wired separately. It’s all been working fine ever since.
I remember that the modules were particularly sensitive - needing true split line power supply, appropriate circuit protection, and good short star earthing.
I created a PCB for each channel with a decent amount of copper to ensure good current delivery and to provide somewhere to mount both some decent high grade electrolytic capacitors and the rectification using discrete diodes for the power supply - sourced from two very expensive (on my student income) toroidal centre tapped transformers.
I also added a really high quality relay setup that was controlled by a time delay circuit, giving a 2 second delay between power application and connection of the speaker output, to protect the speakers from the inrush “pop” that was disconcerting at best.
I built a second “Semi Passive Pre-Amp” that for all but the Phono stage was purely an attenuator using an array of carefully chosen and matched metal film resistors arrayed around a modified 60 position rotary switch.
The phono stage was an RIAA compensating design I built from a magazine of the day - but I forget which one, and that had a separate PSU that needed to be switched on (off for all other inputs).
As my ownership of vinyl was abruptly curtailed by a burglary from my pretty insecure student digs in what was at the time a dodgy part of London. I moved with the help of insurance money to these new tangled CD things (I still have my Toshiba XR-Z90 CD player) and so the phono stage got removed when I re-cased this at the same time as re-casing the two power amps in about 1986.
I found it interesting they left my home built amp/s but nicked over 600 vinyl LP’s - they must have had taste - and a big truck to remove it all..
Anyway, the power amp and “passive pre-amp” (now just an line level attenuator) were in constant use with a variety of speakers from their construction until 2006.
A house move consigned them to the attic when my Heybrook HB3’s suffered irreparable damage in transit (Italy to UK). Two years ago, I got gifted an original set of ex BBC radio station LS 3/5a speakers and they meant the old Hi-Fi came out of retirement. It still sounded pretty good. It replaced a rack of NAD stuff that I’d got bored with and frankly - I think the old Toshiba and my home built combination sounded far better with the LS 3/5a’s - probably the power needed to drive them properly.
A refurbishment of the house saw the entire setup moved to my (very clean) workshop, a big 5m x 15m concrete panelled space. The sound in there isn’t at all perfect, but it does ensure we can hear whatever is on! I’ve recently added a Chromecast Audio as a Roon endpoint too.. since that allows access to radio and much more.
My “house” system has gone all minimal and digital now, following a long search and a lot of listening - with an Innuos Zenith SE as primary source (using Roon with Tidal and Qobuz) plus my ripped library of nearly 2000 CDs in FLAC format on an attached NAS. The Innuos plays either directly (or through a Graham Slee Majestic DAC analogue side) to a second hand pair of Kii Three speakers and a Kii controller. In my listening room (a vaulted ceiling space of 3.8m x 4.8m - with no room treatments - it’s absolutely spectacular.
They are two very different systems at price ranges that reflect the stage in life they were both acquired (or built!) and I like both of them.
Don’t let anyone say the MOS248’s are poor though. Correctly powered and protected they provide a great high quality sound and one that’s not overly cold or clinical.
I’d agree with previous comments that the RS data sheets were of far more practical use than those form ILP themselves.
If you have these modules and are considering using them - do. I doubt you’ll be disappointed.
I found them here - so thank you.
I built two monobloc power amps in 1982 using the MOS248 modules and these were later housed in the same case - although remaining wired separately. It’s all been working fine ever since.
I remember that the modules were particularly sensitive - needing true split line power supply, appropriate circuit protection, and good short star earthing.
I created a PCB for each channel with a decent amount of copper to ensure good current delivery and to provide somewhere to mount both some decent high grade electrolytic capacitors and the rectification using discrete diodes for the power supply - sourced from two very expensive (on my student income) toroidal centre tapped transformers.
I also added a really high quality relay setup that was controlled by a time delay circuit, giving a 2 second delay between power application and connection of the speaker output, to protect the speakers from the inrush “pop” that was disconcerting at best.
I built a second “Semi Passive Pre-Amp” that for all but the Phono stage was purely an attenuator using an array of carefully chosen and matched metal film resistors arrayed around a modified 60 position rotary switch.
The phono stage was an RIAA compensating design I built from a magazine of the day - but I forget which one, and that had a separate PSU that needed to be switched on (off for all other inputs).
As my ownership of vinyl was abruptly curtailed by a burglary from my pretty insecure student digs in what was at the time a dodgy part of London. I moved with the help of insurance money to these new tangled CD things (I still have my Toshiba XR-Z90 CD player) and so the phono stage got removed when I re-cased this at the same time as re-casing the two power amps in about 1986.
I found it interesting they left my home built amp/s but nicked over 600 vinyl LP’s - they must have had taste - and a big truck to remove it all..
Anyway, the power amp and “passive pre-amp” (now just an line level attenuator) were in constant use with a variety of speakers from their construction until 2006.
A house move consigned them to the attic when my Heybrook HB3’s suffered irreparable damage in transit (Italy to UK). Two years ago, I got gifted an original set of ex BBC radio station LS 3/5a speakers and they meant the old Hi-Fi came out of retirement. It still sounded pretty good. It replaced a rack of NAD stuff that I’d got bored with and frankly - I think the old Toshiba and my home built combination sounded far better with the LS 3/5a’s - probably the power needed to drive them properly.
A refurbishment of the house saw the entire setup moved to my (very clean) workshop, a big 5m x 15m concrete panelled space. The sound in there isn’t at all perfect, but it does ensure we can hear whatever is on! I’ve recently added a Chromecast Audio as a Roon endpoint too.. since that allows access to radio and much more.
My “house” system has gone all minimal and digital now, following a long search and a lot of listening - with an Innuos Zenith SE as primary source (using Roon with Tidal and Qobuz) plus my ripped library of nearly 2000 CDs in FLAC format on an attached NAS. The Innuos plays either directly (or through a Graham Slee Majestic DAC analogue side) to a second hand pair of Kii Three speakers and a Kii controller. In my listening room (a vaulted ceiling space of 3.8m x 4.8m - with no room treatments - it’s absolutely spectacular.
They are two very different systems at price ranges that reflect the stage in life they were both acquired (or built!) and I like both of them.
Don’t let anyone say the MOS248’s are poor though. Correctly powered and protected they provide a great high quality sound and one that’s not overly cold or clinical.
I’d agree with previous comments that the RS data sheets were of far more practical use than those form ILP themselves.
If you have these modules and are considering using them - do. I doubt you’ll be disappointed.
Perhaps the MOS248 was better in that regard?
Mine certainly seem to have stood the test of time.
I was VERY careful to sort out grounding and PSU though - and I think that, along with a short capacitor coupling may be key for these...
ILP is going back to the 1970's.
There were loads of ad's in magazines for their modules around that time.
I looked at them at one time for a mobile disco amp but settled in the end for the Maplin 225WRMS disco amplifier.
Not quite sure why the potted them. I would have thought that would encourage over heating and unreliability.
There were loads of ad's in magazines for their modules around that time.
I looked at them at one time for a mobile disco amp but settled in the end for the Maplin 225WRMS disco amplifier.
Not quite sure why the potted them. I would have thought that would encourage over heating and unreliability.
I remembering phoning ILP about reliability issues with the IL,P modules. Ian the boss where the ILP gets it's name said that for continuous running a music RMS must be reduced to 1/6 th for continuous running. After a little research I realised that this would be true of nearly any amplifier. My brother thought that the encapsulation maybe didn't help when an ILP was at the limit. After that all went well. I think Hy60 could give 15 continuous watts. I found this was in reality 28VA with the load I was using. One unit like this has just died after 20 years running a Garrard turntable motor via a transformer!
An ironic twist. Hypex are cautious about overstating the efficiency of their products. By mistake I left one running at what I thought was 2.83 Vrms output and was 28.3 Vrms or that region. With no heatsink it survived! This went on for hours! The group of testing resistors were fried and the test probes also. The module perhaps 45 C.
If you want a tough eight ohm load the Bosch 1600 watt cooker elements that is 32 ohms with a centre tap is suitable. If the tap is used 8, 16, 32 ohms are available. The generic types that work very well can be less than £10. The type is often called half moon. I would imagine inductance isn't high.
ILP products were beautifully presented and very low cost. For my application a heat sink of 0.6 degrees per watt and tip35/36 transistors might have helped with switch mode PSU to tightly control excess voltage. Elimination of electrolytic capacitors also if encapsulated. That wasn't really available then as a package.
An ironic twist. Hypex are cautious about overstating the efficiency of their products. By mistake I left one running at what I thought was 2.83 Vrms output and was 28.3 Vrms or that region. With no heatsink it survived! This went on for hours! The group of testing resistors were fried and the test probes also. The module perhaps 45 C.
If you want a tough eight ohm load the Bosch 1600 watt cooker elements that is 32 ohms with a centre tap is suitable. If the tap is used 8, 16, 32 ohms are available. The generic types that work very well can be less than £10. The type is often called half moon. I would imagine inductance isn't high.
ILP products were beautifully presented and very low cost. For my application a heat sink of 0.6 degrees per watt and tip35/36 transistors might have helped with switch mode PSU to tightly control excess voltage. Elimination of electrolytic capacitors also if encapsulated. That wasn't really available then as a package.
I worked in Medical Electronics at the time of building my MOS248 based power amplifier/s and we regularly used potting to ensure good heat sinking and resistance to moisture in high humidity environments. It also cut out any vibration issues on circuits sensitive to movement.
InThis case, I suspect the posting served two purposes. Firstly, improved thermal conductivity and secondly a primitive but effective copy protection to prevent reverse engineering...
Mine are still working very well, and so far I’ve had zero issues with them.
A workshop amplifier. Also semi active speakers. That is a port loaded speaker where the airflow cools the amplifier back. Use passive speaker. Then build a very simple preamp. Make up the rest for Christmas. That idea is not so stupid. Wharfedale Active Diamonds were well liked and much the same.
ILP were closer to Belgium than where I live. Canterbury. The transformers were first of the type in the UK. Antrrim are a versoin of them. Rega used them.
If you get too many wanting them Velleman have a very similar idea as a kit. If you keep it simple it should be very good.
ILP were closer to Belgium than where I live. Canterbury. The transformers were first of the type in the UK. Antrrim are a versoin of them. Rega used them.
If you get too many wanting them Velleman have a very similar idea as a kit. If you keep it simple it should be very good.
If you do that you will increase the current output into low impedance. If eight ohms not much will change. A larger power supply would be required or at least as large as a stereo amplifier.
If a 10K potentiometer is fitted between the hot input terminals the signal fed to the centre connection. The signal adjusted until equal between both channels. A low grade speaker between the hot output terminals is a way of balancing the output. Music used as the test. Make the sound as low as possible the terminals then parallelled. Series bridge is interesting. Unfortunately the heatsink isn't large enough.
Some loudspeakers benefit from parallel bridge. Gale 401, Linn Sara and Isobaric come to mind. Often it's not the parallel bridge it's just the monobloc format. The Quad 405 being a prime example. The sound quality of that amplifier is mostly it's lack of current rather than the feedforward error correction of class B.
If a 10K potentiometer is fitted between the hot input terminals the signal fed to the centre connection. The signal adjusted until equal between both channels. A low grade speaker between the hot output terminals is a way of balancing the output. Music used as the test. Make the sound as low as possible the terminals then parallelled. Series bridge is interesting. Unfortunately the heatsink isn't large enough.
Some loudspeakers benefit from parallel bridge. Gale 401, Linn Sara and Isobaric come to mind. Often it's not the parallel bridge it's just the monobloc format. The Quad 405 being a prime example. The sound quality of that amplifier is mostly it's lack of current rather than the feedforward error correction of class B.
I wired up an ILP preamp and amp for a friend of a friend who didn't have the skills to complete the project. I remember testing it out with my friend's VHS HiFi deck acting as a TV tuner to watch an A-Team episode that by some lucky coincidence had some good music on the the soundtrack.
I'm pretty sure I read a magazine review that discovered some instability with the modules they tested. Possibly "Audio Amateur" or "Popular Electronics".
In other module news, a friend came across an unwired Mullard Unilex integrated amp kit dating from about 1969, made up from the sort of low-fi modules used in TVs and inexpensive phonographs of the era. I'm tempted to wire it up for him, but it's designed for UK line voltage and 16 ohm speakers, so a completed unit isn't a particularly useful thing 50 years in the future. OTOH, a completed unit could sit with his other decorative vintage audio stuff and not take up space in his workshop, so that's something.
I built my first "real" amp using Sanken modules, but after blowing up a number of them, I came to appreciate the advantage of amps where you only need to replace output devices, not the whole module.
I'm pretty sure I read a magazine review that discovered some instability with the modules they tested. Possibly "Audio Amateur" or "Popular Electronics".
In other module news, a friend came across an unwired Mullard Unilex integrated amp kit dating from about 1969, made up from the sort of low-fi modules used in TVs and inexpensive phonographs of the era. I'm tempted to wire it up for him, but it's designed for UK line voltage and 16 ohm speakers, so a completed unit isn't a particularly useful thing 50 years in the future. OTOH, a completed unit could sit with his other decorative vintage audio stuff and not take up space in his workshop, so that's something.
I built my first "real" amp using Sanken modules, but after blowing up a number of them, I came to appreciate the advantage of amps where you only need to replace output devices, not the whole module.
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To aid stability perhaps copy what Naim Audio did. That is add 0R22 to output plus. The speaker cable twisted 5 times in two metres. I opened an ILP module and saw no output choke that seems to be the usual answer. Some people prefer the Naim way. Bass will be if anything improved by doing this due to mild under damping as in 1950s amplifiers.
This suggests parallel bridge isn't a great idea.
This suggests parallel bridge isn't a great idea.
Because you could replace the output transistors when you blew them?
Which is what happened to a lot of the ILP modules. The biggest problem with them is that they can only put out rated power on a regulated supply, at the recommended max. Any real supply is going to drop, and you don’t get rated power. If you use them that way, as a lower powered amplifier, they are fine. Experiments at running them at higher voltage, dropping to rated voltage under load, always ended badly.
Which is what happened to a lot of the ILP modules. The biggest problem with them is that they can only put out rated power on a regulated supply, at the recommended max. Any real supply is going to drop, and you don’t get rated power. If you use them that way, as a lower powered amplifier, they are fine. Experiments at running them at higher voltage, dropping to rated voltage under load, always ended badly.
Farnell still do ilp modules
https://uk.farnell.com/ilp-electronics/hy2005/ic-amp-power-psu-120w-2005/dp/1211581
https://uk.farnell.com/ilp-electronics/hy2005/ic-amp-power-psu-120w-2005/dp/1211581