The Official "Ambrosi Amps' Retrofit Power Amps for the Profiler" thread

    Hello everyone :)


    After opening a thread on TGP about Ambrosi Amps' K-Power amps I couldn't but do the same on our board, even tho basically all the information is already been supplied in other threads.


    Some pictures first :)
    Note: images are hi-res, just enlarge them for more details.



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    The currently available models are


    ATM-68
    Nominal power: 22W / 16ohm, 38W / 8 ohm, 68W / 4ohm.
    Only available @ 230 V.


    ATM-70
    Nominal power: 30W / 16ohm, 50W / 8 ohm, 70W / 4ohm (90W / 4 ohm @ 5% THD).
    Available on demand @ either 230 V or 115 V.



    These are the main characteristics of the ATM series:

    • Retrofits the Profiler with an elegant brushed aluminium plate;
    • All-analog technology;
    • You can use one or two cabs in parallel for more volume and power!
    • A stand-by switch has been added for (dis)connecting the unit without having to switch it off / on.
    • Efficiency: this small beast is extremely loud! 121 dB with 2 1x12", 100 dB/1 W/1 m cabs. Add 3 dB for 2x12" cabs (124 dB total) and 6 more dB for 4x12" cabs (130 dB total. This is loud).
    • The unit is optionally delivered with one single convenient, Y-shaped 180 cm (70") power cord in order to feed both the Profiler and the K-Power Amp at the same time. No need for two separate cables / power supply / outlets.
    • The unit is optionally delivered with a short and convenient 20 cm (8") signal cable that allows to not have to re-cable the system whenever the use switches from passive cabs to active cabs / monitors / PA / mixing desk / audio interface.
    • Service Monitor out! No need for disconnecting and reconnecting the unit depending on your needs! You can leave the K-Power Amp always connected to your Profiler.
    • In its maximum configuration with a K-Power amp, the Profiler can drive at the same time 2 passive cabs, one active cab / mixing desk / recorder, and at the same time supply a stereo (un)balanced signal to FOH / studio monitors / DAW / mixing desk.


    Note: the two above-mentioned cables are optionally available as the Cord Pack.


    We decided to make it optional in order to keep the amp price low, since many users would already have got what they need in order to connect and power-feed their unit, or they might prefer to choose the cables by themselves.


    More detailed characteristics about the ATM series in the next post :)


    For any inquiry, do not hesitate to contact me @ ambrosiamps at gmail dot com.

    Here follows a more detailed list of the K-Power Amp series' characteristics.


    For readability's sake, data refer to the ATM-70 where different.



    INTRODUCTION


    K-Power amp's technology, analogic but not banal, studied but not expensive, is the result of years of research in the field. The design is free of any kind of compromise on materials; solid-state technology has been chosen in order to offer the best results in terms of linearity and reliability. The quality of components, from the transformer to each single component is aimed at offering the musician a great quality.


    Circuits use carbon-film resistors for the least thermal noise; ceramic, multi-layer and electrolytic capacitors; an oversized transformer, a 2-mm aluminium frame for the ultimate lightness and other peculiarities.


    Designed around the National LM3886 integrated circuit, the ATM amps exhibit a number of protection mechanisms:

    • The Under Voltage Protection serves the purpose of preventing the "bump" on the loudspeakers when switching the unit on/off.
    • The output is protected against both short-circuits and overloads.
    • Two stages safeguard the chip against overheating: the SPIKe (Self Peak Instantaneous Temperature °Ke) chimes in in case of the final transistors' temperature raising; the second protection circuit operates on the whole chip interdicting its operation when the temperature goes over 165° C. The ATM amp also host two 2-A T fuses on the power supply line.


    DATA SHEET

    • Nominal Voltage: 230 / 115 V AC (on demand) / 50-60 Hz.
    • Power chip: IC National LM3886, thermal convection cooling.
    • Minimum / Maximum power absorption: 26 / 120 VA.
    • Power Absorption in stand-by: 23 VA.
    • Voltage Gain: 27 dB.
    • Instantaneous Output Power: 135 W.
    • Frequency Range: 27 Hz - 105 kHz +0.5 / -3.0 dB.
    • Damping Factor: 200.
    • Distortion Factor: THD+N: 0.1% 20-20,000 Hz.
    • Signal-to-Noise Ratio: > 92 dB.
    • Noise Voltage: 2.0 uV RMS, unweighted.
    • Input Sensitivity @ 4 ohm: -0,6 dBV / 0.72 V.
    • Solid-state Bridge Rectifier Stage.
    • Dual power supply 34 V per branch with 2 x 2 AT, 250V, 5x20 mm fuses.
    • 0.5 A T, 250V, 5x20 mm fuse.
    • Protection Circuits: Over-Voltage, Under-Voltage, Short To Ground, Overloads, SPiKE Protection, Over-temperature.
    • Mute / Active switch. Power switch.
    • Main frame: 2-mm aluminium.


    INPUT


    1/4" unbalanced, 22 kohm.
    Maximum Input Level: 2.0 Vpp @ 4 ohm. Settable through on-board trimmer.



    OUTPUTS

    • Monitor Out: 1/4" unbalanced for a line-level connection (external power amp, recording device, mixing desk and the like).
    • Loudspeaker Outs: 2 x 1/4". Accept loudspeakers in the 4-16 ohm range (minimum load: 1 cabinet @ 4 ohm or 2 cabinets @ 8 ohm).


    SIZE


    360 x 117 x 88 mm (14,2" x 4,6" x 3,5").
    Internal depth: 76 mm (3,0").
    Weight: 2,0 kg (4,4 lbs).

    Hi, Gianfranco, only a small notice to you. Shouldn't you put CE marking on the product to show that it meets EC directives? I didn't find any on the photos. Just mentioning it, so you wouldn't have any problems. ;)

    Hey Peto, the photo - taken in Ancona, quite far from my place - is just a demo I guess.
    The production place is far from Rome, my work takes place in remote.
    Since I'm not really into the matter, I leave all the legal and Administrative issues to Andrea :)


    Thanks for your note :)

    Quote from waraba


    So the product is considered as a mature one yet ?


    Yep!


    I'm in the queue as we speak, getting the 70 model. Shouldn't be too long, now.

    I'm just trying to be as truthful to my experience and personal opinion that I'm clearly presenting only as a personal opinion no more no less in an honest and truthful discussion about equipment.

    I should receive my ATM-70 very soon! :)


    I'll report back too! I will use it with a FRFR passive cab for the moment but with the new firmware 3.0 I will certainly get myself a good little guitar cab!

    Quote from Robman

    Whats the lead time again from order to completion typically?


    Since Ambrosi Amps is a small company, parts are bought in batches. If parts are in stock, the assembly and test takes about 5 days.
    So depending on the specific moment you might experience some delay due to the laboratory waiting for supplies.


    Quote from waraba

    How great ! Excellent job from both of you :)


    So the product is considered as a mature one yet ?


    Yes, already shipped\shipping :)



    Quote from Guitartone

    Brilliant!!!


    Incoming, can't wait to make a lot of LOUD noise. :thumbup:



    Ha :D
    While you're there, what about grabbing a couple of 4x12" just to make the noise even LOUDER?
    Have them wired @ 8 ohm for the ultimate hell :D


    :thumbup:

    Quote from Zapman

    Very nicely done! Looks like a top notch product. :thumbup:


    Thanks Zapman, appreciate it :)



    Quote from db9091

    This is a superb price.


    What are the differences between this and the ISP Stealth in terms of practical usage?


    I did not deeply study the ISP. But from what I see on the Internet:

    • The ISP is a stereo amp, while the ATMs are mono amps.
    • The ISP declares a higher nominal power (they seem to not declare the measurement conditions tho) and a lower weight (they don't include the needed external power supply).
    • The ATM natively retrofits the Profiler, is steadily fixed and turns the Profiler into a real amp head, while the ISP is something you can place in the back cavity of the Profiler; not sure whether the power supply fits itself.
    • The ATM doesn't need an external power supply.
    • The ATM is an all-analog amp, and sounds like an old, traditional, good SS amp. I can't "prove" this is measurable, but I know that the feeling is good when I play one :)
    • With the Cord Pack (or any equivalent solution) you just need one mains outlet to supply power to both the Profiler and the ATM.
    • With the ATM you can connect two (8 or 16 ohm) cabs at the same time in mono for a much higher volume and efficiency. They might be of different kinds as well (e.g., one for guitar, the other one linear or for bass).
    • With the ATM you can still use your Monitor Out while feeding one or two passive cabs (see above). For example in order to use a further active cab at the same time, another poweramp, to feed an IEM system, a recorder or whatever you need\want.

    This is what stands out by a quick look at the ISP's specs. Hope the above is accurate! Please correct me if anyone notes anything inconsistent.


    :)

    Edited 2 times, last by viabcroce ().

    Quote from Peto

    Hi, Gianfranco, only a small notice to you. Shouldn't you put CE marking on the product to show that it meets EC directives? I didn't find any on the photos. Just mentioning it, so you wouldn't have any problems. ;)



    The CE testing would as far as I know cost €20,000+ and the cost of same would need to be passed on to us the consumer ......I may be wrong on this ...


    One way around it is to ensure that each individual item is a prototype which seems to be the way the design is as per each particular users preferences.....


    I don't have a problem with the CE being omitted from a reputable designer / manufacturer if it means a cost saving


    This is just my opinion of course

    Hey Rob,


    thanks for your comments :)


    Yes, not my field but I can imagine these things are expensive, specially in Italy, the country where things are made in order to not work (and to not let anything work properly). A startup can really kill you here. Business must not start, unless you are a big lobby or a multinational corporation.
    ...And justice must not work, and education, and tourism, and research as well...


    ...but I'm really digressing, am not I?

    I only know this because an amp builder / designer friend of mine ( who did some work for U2 , Van Morrison etc... ) looked into getting CE registration and the costs made it non viable.He said that the only way to do it would be if you could bring the manufacturing costs down and get the volumes for sale quite high....as I said he now makes minor modifications to each one that he makes so that each one is a prototype ....


    point I'm making is that its not just in Italy , its across the 'European state' as a whole. Policy is to globalise and monopolise everything it seems for the benefit of the large companies.... <X

    I see this sort of thing in America. The political mantra is "Captialism" but the lobbying is kill competition in favor of our large corporation. It's why I like to suport local produce and small companies in general.


    Luckily for me, Kemper fits in with my philosophy, or else I'd have to become shallow and STILL buy one, lol!