JezmondTutu
pfm Member
Ah - it was worth a thought! I'd still try to borrow one, you may find the Arcam works better with your speakers but at least you'll know the answer then.
Arcam, Klout or what
- Thread starter Minio
- Start date
Ah - it was worth a thought! I'd still try to borrow one, you may find the Arcam works better with your speakers but at least you'll know the answer then.
Minio
Kind of Sort of Not really...
"....have you considered an ARCAM Alpha 9 preamp..."
Not easy to find but I'll keep my eyes out for one.
I must have had a bad sample of an A80 as it was one of the worst amps I've heard.
The Naim pre seems a good match with my 10P. Factoring in the speakers which have been described as 'fast with a prominent tweeter' may account for the subsequent synergy. I don't hear any such aggressive characteristic so ascribed to the Momentums in blogs, reviews etc.
Thanks for the offer Jez.
Going beyond NAP250 to 300 or 500 is a bit beyond my resources even though many recommend amps in the 5 figure region to drive the Momentums which are still in the 4 figure region.
Not easy to find but I'll keep my eyes out for one.
I must have had a bad sample of an A80 as it was one of the worst amps I've heard.
The Naim pre seems a good match with my 10P. Factoring in the speakers which have been described as 'fast with a prominent tweeter' may account for the subsequent synergy. I don't hear any such aggressive characteristic so ascribed to the Momentums in blogs, reviews etc.
Thanks for the offer Jez.
Going beyond NAP250 to 300 or 500 is a bit beyond my resources even though many recommend amps in the 5 figure region to drive the Momentums which are still in the 4 figure region.
Quite a few people have said that the A80 was not ARCAMs finest product but thats the way it goes with HiFi. I have used my A80 with several different speakers and it never misbehaved.
I still feel its a corker of an amp and I think the A80 was one of the better amps in the Diva range. Its also interesting to note that quite a few reviewers and dealers have said ARCAM fixed all the A80s faults (whatever they were) when ARCAM designed the A70. What they didnt know that the A70 was an A80 with a smaller power-transformer because Nuvotem-Talema were no longer able to supply the A80s power transformer so an alternative transformer had to be found in a hurry. Everything else in the A70 was identical to the A80. I lost my faith in the HiFi reviewing intelligentsia after that, but thats another story for another thread.
As to naim pre-amplifiers not matching non-naim amplifiers, I was more referring to the DIN to RCA level mismatch rather than any subjective function of its performance. But if it works for you than thats a good thing.
The Alpha 9 is a pretty textbook pre-amplifier and doesnt use a rotary encoder and volume control IC like most of Arams later amplifiers. Some users feel a little uncomfortable with a rotary encoder and volume control IC despite the many advantages they offer.
Another thought; if you really want to go for a naim pwr-amp to match your NAC72, the NAP 180 is cheaper than a NAP250 or even a NAP140. The 140 is the most pwerfull of naim half sized "shoe-box" amplifiers an is good for 45 watts into 8 or 70 into 4 ohms. The 140 and the 72 do look quite cute sitting next to each other on the shelf and my little 140 punches well above its weight.
LPSpinner
per flemming
Registered User
In fact 140, 180 and 250 contain nearly same amplifier boards with PSU & cabinet beeing the difference (price aside)
IMO much better amplication than Arcam but each to their own
IMO much better amplication than Arcam but each to their own
Minio
Kind of Sort of Not really...
"...referring to the DIN to RCA level ..."
No mismatch at this stage although a non standard phono to DIN cable is required with the correct pins connected to the Naim. Once that is in place the combination works beautifully and the volume range is operationally ideal - lovely and smooth as the pots in the Naim are proper quality.
No mismatch at this stage although a non standard phono to DIN cable is required with the correct pins connected to the Naim. Once that is in place the combination works beautifully and the volume range is operationally ideal - lovely and smooth as the pots in the Naim are proper quality.
Yup and dont forget the 135 as well, all the naim amplifiers in the olive and the later Chrome bumper series except the Little NAP90 use the same amplifier modules.
The 140 and the 180 also use the same PSU P.C.Board but the 180 gets a bigger transformer and the 180s transformer has separate windings for left and right channels.
However, I wouldnt be too quick to dismiss the ARCAM amplifier. The naim circuit is very basic and deviates very little from the application notes in the semiconductor circuit handbook. The ARCAM circuit is much more mature and well thought out, even to the point of using drivers with the MOSFET output stage, something the original Hitachi circuit didnt do. This makes the Alpha 10 a much better developed circuit the original design in the Hitachi semiconductor handbook. ARACM also use a well-specified power supply without being over zealous or silly.
"...referring to the DIN to RCA level ..."
No mismatch at this stage although a non standard phono to DIN cable is required with the correct pins connected to the Naim. Once that is in place the combination works beautifully and the volume range is operationally ideal - lovely and smooth as the pots in the Naim are proper quality.
Yes the 72 uses the ALPS Big Black high precision pot that is smooth and has a very precise channel balance. Its interesting to note that the later full sized naim pre-amps ended up using the lesser blue Alps pot. I borrowed a 102 for a short while with a view to upgrading. The NAC102 had all sorts of channel balance issues, the 72 just worked, if it works for you (and it obviously does) than excellent.
Oh and yes, you do need to be aware that naims 4 pin din plug wiring on the pre-amp is not standard so you will need to make up your own leads. I have to keep two sets of Din leads, one set for my QUAD gear and another set for my naim stuff, it all has to be clearly marked or it can get a little confusing.
Happy listening.
LPSpinner.
Minio
Kind of Sort of Not really...
Some interesting technical stuff there LPspinner
I note that the original upgrade stage for the Alpha 10 was to a add a 10P to the integrated.
Thus you'd have even more power but still being fed by the rather bland (IMO) preamp stage of the 10 Integrated. Much better to add a half decent pre to a half decent power amp.
I note that the original upgrade stage for the Alpha 10 was to a add a 10P to the integrated.
Thus you'd have even more power but still being fed by the rather bland (IMO) preamp stage of the 10 Integrated. Much better to add a half decent pre to a half decent power amp.
Some interesting technical stuff there LPspinner
I note that the original upgrade stage for the Alpha 10 was to a add a 10P to the integrated...
Yes ARCAM was / is a proponent of passive Bi-amping where you use one amplifier for the treble and the separate power amplifier for the bass when your speakers have a split crossover. This must not be confused with active operation where you use an active crossover ahead of the amplifier and remove the crossover from the speakers. Active operation has some very real and tangible benefits, passive Bi-amping much less so.
I used passive Bi-amping for a while but to be honest I found the improvements to be marginal at best and it just got messy with twice as much cable running piled up behind the equipment, I no longer bother. My A80 is used as a pre-amp and the P90 gets used as a power-amp, the amplifier in the A80 just sits there doing nothing or sometimes driving headphones via the headphone socket on the A80.
You dont actually get more power; the existing power amplifier(s) are just required to operate over a narrower frequency range.
LPSpinner.
Minio
Kind of Sort of Not really...
"You dont actually get more power; the existing power amplifier(s) are just required to operate over a narrower frequency range..."
So, like me, you found it a bit of a waste of time (and electricity and space) It did sound different though. I found it tightened up the sound which seemed more beneficial at lower levels. There would be some variance with different speakers I would imagine.
So, like me, you found it a bit of a waste of time (and electricity and space) It did sound different though. I found it tightened up the sound which seemed more beneficial at lower levels. There would be some variance with different speakers I would imagine.
Arkless Electronics
Trade: Amp design and repairs.
Yup and dont forget the 135 as well, all the naim amplifiers in the olive and the later Chrome bumper series except the Little NAP90 use the same amplifier modules.
The 140 and the 180 also use the same PSU P.C.Board but the 180 gets a bigger transformer and the 180s transformer has separate windings for left and right channels.
However, I wouldnt be too quick to dismiss the ARCAM amplifier. The naim circuit is very basic and deviates very little from the application notes in the semiconductor circuit handbook. The ARCAM circuit is much more mature and well thought out, even to the point of using drivers with the MOSFET output stage, something the original Hitachi circuit didnt do. This makes the Alpha 10 a much better developed circuit the original design in the Hitachi semiconductor handbook. ARACM also use a well-specified power supply without being over zealous or silly.
Yes the 72 uses the ALPS Big Black high precision pot that is smooth and has a very precise channel balance. Its interesting to note that the later full sized naim pre-amps ended up using the lesser blue Alps pot. I borrowed a 102 for a short while with a view to upgrading. The NAC102 had all sorts of channel balance issues, the 72 just worked, if it works for you (and it obviously does) than excellent.
Oh and yes, you do need to be aware that naims 4 pin din plug wiring on the pre-amp is not standard so you will need to make up your own leads. I have to keep two sets of Din leads, one set for my QUAD gear and another set for my naim stuff, it all has to be clearly marked or it can get a little confusing.
Happy listening.
LPSpinner.
Spot on
Other than that it's basically a quasi complementary version of the Hitachi circuit...Minor gains can possibly be made where the speakers are particularly reactive and difficult to drive or one of the power-amplifiers has issues in handling difficult loads. Interestingly though, ARCAM amplifiers are usually pretty good with tricky speakers and are very load tolerant.
The Other reason I No longer use Bi-Amping is I am currently using a pair of Yamaha NS1000s which dont have a split crossover, and because of the NS1000s heritage status I dont intend to modify or bodge with them in any way.
I actually tried Bi-Amping with my naim setup at one stage (72/HiCAP into a 250 and a 140) into my ELAC 207.2 and the results were actually worse then either the 140 or the 250 on their own, so it is definitely a case-by-case scenario.
To be honest better and more cost effective gains can be made by spending the cash on better speakers or investigating a proper active setup.
LPSpinner.
Spot on
When I was heavily into DIY I built several amplifiers based on the Hitachi circuit and to me they all sounded a bit flat and had pretty average damping factors. On the test bench they also seemed to object to highly reactive loads by increasing distortion. The Drivers (and pre-drivers) used by ARCAM should buffer the VAS stage nicely from the high currents in the output stage and protect against most of that load based distortion.
SELF explains this very nicely in some of his texts on amplifier design.
Unfortunately SELF wasn't writing about amplifier design in my DIY-ing days and I just don't have his intellect and knowledge.
LPSpinner.
EDIT
PS: when I think back about the circuits I used, they were a fully complementary source follower output stage not dissimilar to the one listed below: This circuit uses a 220 Ohm resistor to help isolate the VAS stage from the large currents in the output stage.
To try and get around the average damping factor and increased distortion into low impedance / reactive loads, I just paralleled the output devices. My final design iteration had 4 power MOSFETS per rail (8 per channel) and I still wasn’t happy. All I really needed to do was to insert a driver transistor between the VAS stage and the output MOSFETS, this probably would have solved everything. Also the DC servo around the NFB loop like the ARCAM uses would have helped the low frequency distortion quite a bit as well.
Its also interesting to note that Silicon Chip magazine who published this design no longer use MOSFETS in their amplifier designs any more, they seem to have adopted the new SAP series of bipolar transistors that have the built in thermal tracking diodes. They also seem to have adopted most of SELF's ideas about amplifier designs such as current source on the input pair as well as current mirrors in the tails, a buffer on the VAS stage and use a "two pole" miller effect capacitor to push the local feed back corner frequency around the VAS as high as possible so as to get the most effectiveness out of the NFB loop. One day I'll have to get motivated and have a go at building one of the 200 watt versions, they look quite impressive on paper.
LPSpinner.
Minio
Kind of Sort of Not really...
Sounds like you should have another go at building your dream amp!
I've had a look inside the 10P. Only half the space in the case is used. Not surprising when I think that space is allowed for various additional modules. The actual power amp section, mostly a heavy toroid, is about the same size as the Klout or less.
I've had a look inside the 10P. Only half the space in the case is used. Not surprising when I think that space is allowed for various additional modules. The actual power amp section, mostly a heavy toroid, is about the same size as the Klout or less.
Arkless Electronics
Trade: Amp design and repairs.
When I was heavily into DIY I built several amplifiers based on the Hitachi circuit and to me they all sounded a bit flat and had pretty average damping factors. On the test bench they also seemed to object to highly reactive loads by increasing distortion. The Drivers (and pre-drivers) used by ARCAM should buffer the VAS stage nicely from the high currents in the output stage and protect against most of that load based distortion.
SELF explains this very nicely in some of his texts on amplifier design.
Unfortunately SELF wasn't writing about amplifier design in my DIY-ing days and I just don't have his intellect and knowledge.
LPSpinner.
EDIT
PS: when I think back about the circuits I used, they were a fully complementary source follower output stage not dissimilar to the one listed below: This circuit uses a 220 Ohm resistor to help isolate the VAS stage from the large currents in the output stage.
To try and get around the average damping factor and increased distortion into low impedance / reactive loads, I just paralleled the output devices. My final design iteration had 4 power MOSFETS per rail (8 per channel) and I still wasnt happy. All I really needed to do was to insert a driver transistor between the VAS stage and the output MOSFETS, this probably would have solved everything. Also the DC servo around the NFB loop like the ARCAM uses would have helped the low frequency distortion quite a bit as well.
Its also interesting to note that Silicon Chip magazine who published this design no longer use MOSFETS in their amplifier designs any more, they seem to have adopted the new SAP series of bipolar transistors that have the built in thermal tracking diodes. They also seem to have adopted most of SELF's ideas about amplifier designs such as current source on the input pair as well as current mirrors in the tails, a buffer on the VAS stage and use a "two pole" miller effect capacitor to push the local feed back corner frequency around the VAS as high as possible so as to get the most effectiveness out of the NFB loop. One day I'll have to get motivated and have a go at building one of the 200 watt versions, they look quite impressive on paper.
LPSpinner.
I've always quite liked this circuit myself and haven't found even the slightest hint of the limitations you mention finding.... as used by Musical Fidelity, Perreaux, Incatech, Myst, Trace Elliot and loads more...
Drivers are only really needed with several paralleled pairs of output mosfets as, being source followers, most of the gate/source capacitance is bootstrapped by its own output.
I generally prefer mosfets to BJT's myself but ymmv
(I disagree with Self over many issues, as do many other designers, but he certainly did some ground breaking research)
linnfomaniac83
I bet you can’t wheelie a unicycle!
There is actually space to accommodate a third amp channel for home theatre use!
Got Neat momentum 3i's. Amazingly good when driven by a Densen B330+ power amp. And that was with the 3i's plonked on old epos es11 stands. B330+ is expensive though. A densen power amp recently went for £600 in classifieds. A 100 watter I think. So second hand, can be bargains.
The combo was just fabulous though. Will be setting up again for another listen soon. Currently using another system. Got me wondering how Densen pre amps would sound.
The combo was just fabulous though. Will be setting up again for another listen soon. Currently using another system. Got me wondering how Densen pre amps would sound.
Probably true, and I will admit that this circuit is a better than the original Hitachi application handbook circuit. This one uses proper mirrors on the VAS differential pair and a proper current source on the input pair. The original Hitachi version (shown below) only used a resistor to isolate the input pair from the main voltage supply rail.
I also had access to some pretty fancy test equipment at the time. We had a digital spectrum analyzer at work as well as an electronics engineer that knew how to use it. This was really handy for setting the bias on amplifiers. It was here that I could see how variable the crossover region of MOSFETS were and getting the bias perfect was very tricky (and very variable). The spectrum analyzer's official use was for analyzing brake squeal on cars, talk about using sledgehammers to crack wall-nuts; Its a pity that we no longer use that gear and Ive lost access to it. Its a real pain setting bias by measuring voltage drops across resistors and hoping you have got it right.
Yes my ARCAM P90 is the same, you also have a power supply that is capable of powering three power amp channels, but it is only driving two. The P90 has a 600VA transformer driving a 100-watt per channel amplifier (its good for about 170 into four ohms). I am pretty sure the Alpha 10P is a similar situation.
LPSpinner
linnfomaniac83
I bet you can’t wheelie a unicycle!
Probably true, and I will admit that this circuit is a better than the original Hitachi application handbook circuit. This one uses proper mirrors on the VAS differential pair and a proper current source on the input pair. The original Hitachi version (shown below) only used a resistor to isolate the input pair from the main voltage supply rail.
I also had access to some pretty fancy test equipment at the time. We had a digital spectrum analyzer at work as well as an electronics engineer that knew how to use it. This was really handy for setting the bias on amplifiers. It was here that I could see how variable the crossover region of MOSFETS were and getting the bias perfect was very tricky (and very variable). The spectrum analyzer's official use was for analyzing brake squeal on cars, talk about using sledgehammers to crack wall-nuts; Its a pity that we no longer use that gear and Ive lost access to it. Its a real pain setting bias by measuring voltage drops across resistors and hoping you have got it right.
Yes my ARCAM P90 is the same, you also have a power supply that is capable of powering three power amp channels, but it is only driving two. The P90 has a 600VA transformer driving a 100-watt per channel amplifier (its good for about 170 into four ohms). I am pretty sure the Alpha 10P is a similar situation.
LPSpinner
It's probably the same amp to all intents and purposes, the original FMJ power amp was (forget the model number).
Minio
Kind of Sort of Not really...
The 10P has 800VA xfmr I think. Quite heavy. The Klout weighs even more though and should have a warning sign on it especially as its half the size!
No its not, Ive got the service manual for both amps. The Alpha 10P is a Quasi-Complementary MOSFET design and the P90 is a Bi-polar design using the newer SAP series Power-transistors.
ARCAM moved away from MOSFET output stages with the introduction of the A85 and its equivalent FMJ version.
The 10P has 800VA xfmr I think. Quite heavy. The Klout weighs even more though and should have a warning sign on it especially as its half the size!
According to the manual the P90 and its FMJ equivalent, the P35, it draws 800VA but inside the transformer appears to be rated at about 600VA. The way they rate a transformer can vary depending on how much voltage drop you will accept for a given power dissipation. If you tolerate a greater voltage drop on the transformer output then you can claim a greater power rating (within reason). I suspect the Alpha 10P is similar; although, 600VA is still very substantial for an amplifier that was designed to do 100 watts.
LPSpinner