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Thread: Take your Genesis audio to the next level - The Mega Amp 2.0 is here!

  1. #31
    Raging in the Streets xelement5x's Avatar
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    So this new version basically works with all models without modifications on the board right, just different install points?
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  2. #32
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    Quote Originally Posted by Guntz View Post
    Any word on production Mega Amp 2.0 boards? I need one for my Genesis 2 VA2.
    Finalizing a design as I'm typing this. I will then purchase the necessary components to assemble the boards and a small batch of 3 boards as well.

    Quote Originally Posted by xelement5x View Post
    So this new version basically works with all models without modifications on the board right, just different install points?
    No PCB modifications required, just component removal (except maybe the Genesis Model 1 - I still need to see how the headphone volume slider works).

    EDIT: I should point out that the PCB design I'm working on is for the Mega Amp 2.0 Pro. The PCB turned out slightly bigger than the smaller original Mega Amp PCB I had designed (but never actually put up for sale), though I would expect the plain Mega Amp 2.0 to be slightly smaller since it's simply using two dual op-amps rather than a quad op-amp, dual op-amp and transistor circuits.
    Last edited by Ace; 01-19-2017 at 06:51 PM.
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

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  3. #33
    Road Rasher AlmostOriginal's Avatar
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    I need this so bad!

  4. #34

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    Will anyone be offering an installation service for these? I don't lack the ability, but I do lack the time. But it would be nice to have this amp in the Genesis that I use to capture footage for my show.

  5. #35
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    I'm considering it, though I haven't made a final decision on that (or which countries I'll accept systems from - Canada, for sure, maybe the US, but elsewhere, I can't say yet). I will be selling pre-assembled boards and some pre-modded consoles, that's for sure.

    I actually have two VA3 Genesis Model 2s with the original Mega Amp installed (one filtered, one unfiltered) that I still need to sell off. If someone doesn't need their Genesis to put out insanely loud sound and can deal with the lack of Sega CD pass-through (and doesn't mind the YM3438; I personally can't stand this chip on the Genesis), they could buy one of those systems.
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

    Note: If you want to contact me on Skype, identify yourself or your contact request will be rejected.

  6. #36
    Road Rasher
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    speaking of sega-cd passthrough, how does that work exactly ? I checked the model 1 schematic and saw A27 and B27 are not connected, how are they wired on model 2 genesis and sega-cd ?

  7. #37
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    They're connected to the final stage of the Sega CD's audio amp. If you look at the Sega CD Model 2 service manual, you will see exactly how it's wired.

    The input first passes through 75ohm pull-down resistors (this is primarily done to prevent the inputs from floating when a Genesis Model 1 is inserted since none of those have Sega CD pass-through) before going into a 10uF series capacitor (negative pole) and a 4.7Kohm series resistor to join with the audio from the Sega CD's audio hardware. Page 2 of the second part of the Sega CD Model 2 service manual shows this; reproduce this circuit for audio mixing on the Sega CD Model 1.
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

    Note: If you want to contact me on Skype, identify yourself or your contact request will be rejected.

  8. #38
    Road Rasher
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    I see. Thanks for the explanation.

  9. #39
    WCPO Agent Helder's Avatar
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    I designed one for the Mini version which I expect to be here in 2 weeks or so and I'd like to get 3 people to play around with it besides myself before committing to a final design build and not going to release a PRO version since I want ACE to release his board as well unlike last time.

    My board will have all 3 variants of the schematic built in with some solder jumpers to choose the console configuration (I'm sick of asking people what system and model it's for so now it's all integrated into 1). All I ask is for people to pay shipping for the board and to be someone who will actually test it and not looking for a freebie (Sorry Arnold101 I won't be sending you one), send me a PM with interest.

  10. #40
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    I might as well take the opportunity to make one thing very clear. I didn't mention this with your original Mega Amp PCB, Helder, but this time, I'm serious. This will go for anybody who wants to make their own boards. Unless you are given explicit permission to alter the design by doing things such as replace electrolytic capacitors with ceramics (itself a VERY bad idea in audio amps and I can't understand why manufacturers did this in the first place in actual products like the last Genesis hardware revisions and even PC sound cards), you're free to do so for your own personal designs, but DO NOT put those into production designs. The 22uF output capacitors, in particular, are really bothersome. 220uF has been chosen on purpose to keep bass levels as high as possible without being overbearing; by using 22uF, you're creating a more significant high-pass filter and killing off some of the bass the Mega Amp would normally deliver.
    So please, to anyone wanting to make Mega Amp 2.0 PCBs, don't design a circuit to sell with changes I do not approve of. If I find such a design, you will be asked to pull it from sale until you redesign your board with the proper components.
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

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  11. #41
    WCPO Agent Helder's Avatar
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    When I made the first version I used ceramic and tantalum caps and I couldn't tell the difference either way and I know electrolytic caps are used in most audio circuits but like I said I couldn't hear any difference between the 2 caps I used.

  12. #42
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    The difference was immediately apparent to me when I was sent audio samples of your board. I think you had sent a sample PCB to Villahed, after which he forwarded samples to me with one channel using your 22uF ceramic capacitors on one channel and the 220uF capacitors in the base design on the other. The difference was immediately apparent with a fairly noticeable drop in bass using the 22uF capacitors. As such, I ask that you do not repeat the use of ceramic capacitors and especially 22uF capacitors on the final output.
    On the subject of PCBs, I have finished my own mixed through-hole/SMD Mega Amp 2.0 Pro PCB (SMD everything except electrolytic capacitors). Remind me where you get your PCBs from? I might still go OSHPark for a small early production batch, but I'm looking to have the final PCB design made on black circuit boards.
    One thing I don't really like about going SMD is the need for so many damn vias. With through-hole boards, I can do a via-less design, but going through-hole with the Mega Amp 2.0 Pro would result in an oversized PCB. Using SMD parts resulted in a board slightly bigger than my revised original Mega Amp PCB, but trace routing was pretty problematic.
    In any case, I'm going to order the necessary SMD resistors, capacitors, transistors and op-amps then get an early mini batch of boards from OSHPark. I have a number of VA0 to VA1.8 Genesis Model 2s and some VA7 Genesis Model 1s that will go up on sale with pre-installed Mega Amp 2.0 Pros as well if I don't find any problems with the OSHPark batch. My boards will be $30US plus shipping from Canada ($25 unassembled for the DIY crowd).
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

    Note: If you want to contact me on Skype, identify yourself or your contact request will be rejected.

  13. #43
    WCPO Agent Helder's Avatar
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    I will test both electrolytic and tantalum caps since 220uf is a common value in both. As for the boards if you want a moderately priced board and about the same shipping time as OSHPark go with DirtyPCB.com, I also use PCBway for large orders and assembly since their price and quality has been great but shipping is kind of expensive so I stick to DHL which gets here in 3-4 days once shipped.

    As for the vias I don't see what the problem is since your using through hole which is a huge via in itself and you will have the solder "nubs" on the underside of the board which elevates it instead of a nice flat surface but that is your choice on the design.

    Routing can always be tricky with SMD parts but you can always get the vias covered (PCBWay has this option) so they aren't exposed and will not cause a short.

  14. #44
    The Best Genesis Master of Shinobi GohanX's Avatar
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    Ace, if I've already got the original Mega Amp installed, is it relatively painless to swap to the new one?
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  15. #45
    Creator of the Mega Amp Raging in the Streets Ace's Avatar
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    If you get a base circuit, it's a direct swap, but if you get the Pro version, you can drop it in, but you will have to add in the Sega CD pass-through yourself as per the instructions in the first post.
    HATES ATGAMES WITH A PASSION


    Mega Amp: An all-new audio circuit for your Sega Genesis/MegaDrive and clones.

    Note: If you want to contact me on Skype, identify yourself or your contact request will be rejected.

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