AudioCircle
Industry Circles => GR Research => Topic started by: Early B. on 6 Oct 2016, 03:10 am
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For those running servo subs --
Has anyone made any upgrades to their A370PEQ plate amps?
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For those running servo subs --
Has anyone made any upgrades to their A370PEQ plate amps?
I can't imagine you could make them sound better, I have never heard bass like the 12" servo subs from any other speaker. YMMV.
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I can't imagine you could make them sound better, I have never heard bass like the 12" servo subs from any other speaker. YMMV.
Well, it's a plate amp, so I'm sure it can benefit from higher quality parts which could result in even better sound.
It would be great if this amp could be placed in a nice chassis to resemble a pair of monoblocks.
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Well, it's a plate amp, so I'm sure it can benefit from higher quality parts which could result in even better sound.
It would be great if this amp could be placed in a nice chassis to resemble a pair of monoblocks.
You can put it in any type of enclosure you want. If you want an aluminum chasis, anodized or not, check out Landfall Systems https://landfallsystems.com/
Mike
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You might be able to beef up the power supply. Ask Brian Ding about it.
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You might be able to beef up the power supply. Ask Brian Ding about it.
I asked him a year ago and didn't get a response.
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I have upgraded a few plate amps in the past simply because it was cheap, and they needed work anyway.
Truth is in the "Sub" range basically sound quality comes down to simply current delivery, and more or less
vibration control.
If the space is there you can upgrade your electrolytic power caps with something like 10% bigger uF in capacitance for faster
cleaner current delivery.
and simply replace your woofer output wires with a better wire harness using something like a solid core copper, or silver mix in 12 gauge or
something again for simply lowering resistance as much as possible for current delivery to the woofer.
I have tried other things like removing cheap diodes putting in High speed bridges etc... But its going to have little effect for all the work
on a Sub only amp.
Vibration by damping everything is always better so obviously separate enclosure can help, but I would not get into all of that as even
then your going to get little results unless the system is so refined, and big you want to take into account every little 2% detail.
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Take some good pictures of them, and I'll try to give you an idea of some possibilities.
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Looks like there are photos right rythmiks site
it looks like you might be able to up the capacitance on the power supply depending on the diameter of the caps and lead spacing, but don't go too big or the in-rush current might start blowing fuses!
(http://www.audiocircle.com/image.php?id=151524)
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I have better ideas than that about making it move current better. Frankly changing to bigger caps probably wouldn't do much of anything, but higher quality may be an option depending on sizing. It's a struggle with aftermarket because they tend to go fatter, and the cheaper ones that come on them often go taller, to achieve the size.
If any of you are wanting to have them modded for you, one could be sent to me to take a closer look and establish a price point for modding. The first person to do so will have to evaluate the changes since I don't have a sub setup atm.
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Great posts, Undertow. I'm at that point of wanting to squeeze out the last 1%, so I'm searching for weak links in my system. The A370 is fairly robust compared to other plate amps, but it's still a plate amp.
There's also some opamps on that board that may benefit from an upgrade. And those sand cast resistors make me cringe.
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If any of you are wanting to have them modded for you, one could be sent to me to take a closer look and establish a price point for modding. The first person to do so will have to evaluate the changes since I don't have a sub setup atm.
I'll send you a PM.
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Great posts, Undertow. I'm at that point of wanting to squeeze out the last 1%, so I'm searching for weak links in my system. The A370 is fairly robust compared to other plate amps, but it's still a plate amp.
There's also some opamps on that board that may benefit from an upgrade. And those sand cast resistors make me cringe.
Yeah honestly OP Amps can benefit to a small degree, but again remember this is a pretty much "Low Frequency" work horse, and honestly there will be very very small benefits vs. something like a DAC, or preamp to go into modding specific circuits with opamps, even bypass caps etc... Mostly in my opinion the most you will push a plate amp is power supply, and like I said possible wiring change to up the overall gauge and quality. Believe it or not I have heard some difference, and definition even on bass drivers doing that.
Power conditioning can help as well, but obviously a high power single outlet conditioner would be best it just depends on how far you want to take it as long as your not fighting ground loops or something in your system already.
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Yeah honestly OP Amps can benefit to a small degree, but again remember this is a pretty much "Low Frequency" work horse, and honestly there will be very very small benefits vs. something like a DAC, or preamp to go into modding specific circuits with opamps, even bypass caps etc... Mostly in my opinion the most you will push a plate amp is power supply, and like I said possible wiring change to up the overall gauge and quality. Believe it or not I have heard some difference, and definition even on bass drivers doing that.
Keep in mind that subs using these amps are often set to go up to 200 Hz or higher in some cases, so they're doing more than the lowest frequencies.
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Hey if you can get a hold of some good opamps cheap enough, and you can de-solder them cleaning the board out go for it! Can't hurt. Unless these already have Opamp sockets on the board than definitely go for it, but I doubt they do in this case, and dealing with removing them is the bigger problem.
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Opamps might help. The trick to removal is a razor blade to cut all the legs next to the chip. Then you can flick away the legs, clean pads a little, apply a touch to the first pad, solder in new opamp/socket and then touch the rest of the legs.
You use the razor blade like a saw, gently.
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UPDATE:
I sent one of my A370 amps to Jeremy (Folsom) so he could evaluate it and make some modification recommendations. Once it arrived, Folsom offered two options that I dubbed, "Level 1" and "Level 2." For now, I opted for the Level 1 mod. Folsom can provide the technical specs on what each level entails.
The amp arrived back home yesterday and I compared it to my stock amp. I used the exact same settings and compared the two amps on the same speaker. My preliminary assessment is that the modded amp definitely sounds cleaner. Actually, the stock amp sounds muddy in comparison, and I never thought I'd ever use the term, "muddy" to describe my servo subs because it's the cleanest bass I ever heard. I had a hunch that the amp could be improved upon, and now I know for sure that there's another level of high fidelity that can be reached by modding the A370.
I would consider this a final mod, after you've exhausted all other significant upgrades, mods and tweaks.
In the next week or so, I'll do some critical listening. My gut tells me that if the bass is cleaner, then the mids and highs, and sound stage may have also gotten a boost.
Here's a before/after pic:
(http://www.audiocircle.com/image.php?id=152696)
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Thanks Earl! Just so you guys know there isn't really anything in the way of replacement capacitors. And the upgrade would probably mostly be psychological with them, as real power delivery isn't just about raw farads. The parts I use and how they're used will give you a much more favorable impression of power than just some beefy capacitors.
Yes I guess I have "Level 1" and "Level 2" mods. Level 2 would make the bass deeper and more expansive, feeling more powerful.
Level 1:
Replacement of both diode bridges with discrete, superior, components.
Dampening both secondary windings.
Adding a DENO to ground which reduces common mode noise.
Twisting output and control wires to reduce their field size.
Level 2:
Mounting discrete (superior) diodes off board, with large filters on the DC side.
Dampening both secondary windings.
Adding a DENO to ground which reduces common mode noise.
Twisting output and control wires to reduce their field size.
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how much do you charge for level 2 mods? What is the turn around time?
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Everyone is welcome to PM me, unless Danny doesn't mind me posting prices. (Rules are strictly informative, not advertising, unless given permission or in correct forum circle)
To answer your inquire in time, 2 weeks is pretty standard since some parts come from Canada. Well, that stands for now, I'll be happy to update time frames if I get buried with them.
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Nice! :thumb:
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Any updates on this project Early ? Have you got the 2nd amp back
Anxious to hear your final impressions
jay
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Any updates on this project Early ? Have you got the 2nd amp back
Anxious to hear your final impressions
Yes, I received the 2nd amp back a couple of weeks ago. I haven't done a critical listening session yet. However, I plan to do so in the next couple of days and will post my final impression. Stay tuned...
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I'm thinking that another useful upgrade would be an improved A-370 volume control. Mine seem to have a lot of "slop," making it difficult to effect small adjustments or to return to previous settings. I'm also thinking that the quality of the pots has an effect on the sound.
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UPDATE:
When I received the first modded amp, I compared it to the stock amp and reported that the modded amp sounds cleaner than the stock amp, without a doubt. The effect was analogous to adding a really good power conditioner.
Once I installed the second modded amp, I heard some "new" micro detail in the bass of songs I've played a zillion times. Other than that, the second modded amp didn’t make the same impact as the first one, but that’s to be expected. I can’t make any other claims beyond better bass definition and improved clarity/detail, which I’ve already described. The sound stage, imaging, etc. appears to be the same.
To elaborate on what I mean by bass definition – for instance, when the upright bass is playing, I can now clearly hear the subtle notes and sustained notes in between the apparent notes (sorry if I’m using the wrong terms here). Likewise with drums – when a drummer is riffing and going a hundred miles an hour, I can hear every strike of the drumsticks. I’ll bet that 99% of audiophiles aren’t hearing this. There’s no way a non-servo box sub can keep up with the speed of sound of a drummer while he’s groovin’, but with the modded amps, it’s now more noticeable.
I don’t have any measurement tools, so I dialed in the amps by ear. Upon first listen, I increased the phase a little. I think it's near perfect now. By the way, dialing in the phase is vitally important. The proper setting is where the magic comes from, where the music locks in.
Overall, it’s a great mod and worth doing when you’ve done everything else. Folsom was exceptional to work with, so no worries there. Maybe some of you guys will go for the Level 2 mod and report back.
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I'll be sending my A-370s to Folsom for Level 2 upgrade next week. Early B is right: Folsom is very easy to deal with and his prices are not horrible. I will be getting my amps back near the end of the month (working around a trip). Stay tuned.
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I'll be sending my A-370s to Folsom for Level 2 upgrade next week. Stay tuned.
Awesome! Looking forward to the review.
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Sorry if I missed this but... Whats the effect on the Warranty?
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how much do you charge for level 2 mods? What is the turn around time?
I'd like to know pricing for both.
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Sorry if I missed this but... Whats the effect on the Warranty?
Most likely voids it. Usually anytime you modify something it voids the manufacturer's warranty.
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Thanks for the repot early B>
We'll likely be sending some to Jeremy as well
jay
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Level 2 is off the table for now. I would need a lot of orders and to print PCBs. I did two amps, turned out great but it takes days to do it by hand, drilling holes it. And requires an extra shipping bkx, mounting etc...
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I was one of the two who got the Level 2 mod and I concur wholeheartedly with what Early B said.
I wrote FOLSOM the following: "I'm liking your mods better and better. I listened to Debussy's La Mer (RCA Shaded Dog original with Charles Munch and the Boston Symphony Orchestra) a couple of nights ago and I heard things in the bass I never heard before. Things like subtle details and textures that I never knew existed on a record I have had for over 50 years and have played on many systems."
How it compares to Level 1 alone, I have no idea: I went right to level 2.
My suggestion is that more of you commit so that Folsom is encouraged to make some Level 2 boards.
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I'd be willing to jump on the bandwagon for a couple boards
Mike
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Mike are you interested in doing the work yourself, or having two units done?
Level 2 requires inserting the board (electrically) between the transformer and the PCB board. This also means bypassing traces on the PCB.
Feel free to PM me.
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Mike are you interested in doing the work yourself, or having two units done?
Level 2 requires inserting the board (electrically) between the transformer and the PCB board. This also means bypassing traces on the PCB.
Feel free to PM me.
Jeremy,
Depends on how complicated it turns out to be. My skills with wood far exceeds those with a soldering iron. :green:
Mike