MaliciousCarp Posted January 19, 2023 Share Posted January 19, 2023 (edited) I have an NTSC 7800 with no mods installed. I recently got a HOKEY basic and dropped it into my concerto cart. I notice that the HOKEY sound is much quieter than the tia sound. I also tried my original Ballblazer and noticed that the POKEY sound was loudly buzzing and distorted. I suspect that my console has developed a hardware problem. Has anyone else seen this before? Where should I start troubleshooting? Edit: fixed formatting. Edited January 19, 2023 by MaliciousCarp Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 19, 2023 Share Posted January 19, 2023 Well the HOKEY does have an issue that Fred has a fix for in regards to the low volume output. Both of the HOKEYs I have suffer from this, but I was able to more or less correct for it with one of them. As for BB having a loud buzz, I'm not completely sure as there isn't really much in the way there. The external audio from the cartridge basically goes through a small filter cap, a resistor and then mixed with the TIA audio and onto the RF modulator from there. So if the TIA audio sounds fine that only leaves small components that could be an issue and neither usually go bad. Make sure the cartridge port is thoroughly cleaned as well as the game cartridge PCB and see if anything changes? 1 Quote Link to comment Share on other sites More sharing options...
Bratwurst Posted January 19, 2023 Share Posted January 19, 2023 24 minutes ago, -^CrossBow^- said: Well the HOKEY does have an issue that Fred has a fix for in regards to the low volume output. Both of the HOKEYs I have suffer from this, but I was able to more or less correct for it with one of them. What was the correction? I assume the ultimate fix will be a firmware update for the HOKEY. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 19, 2023 Share Posted January 19, 2023 7 minutes ago, Bratwurst said: What was the correction? I assume the ultimate fix will be a firmware update for the HOKEY. Well, it is more than that. Fred advised me some hardware changes were made to the current versions that can be replaced out on the original ones. But what I did with the one I put into my old Mateos flash cart was to remove the original output resistors from the Hokey output lines and jumper from there. It still isn't quite at the same level as the TIA, but it is close enough and within variance of original hardware. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted January 19, 2023 Share Posted January 19, 2023 How did you get hold of a HOKEY, Jesse? I have never received an email from Fred with the option of purchasing one (or more - I plan on at least a couple for various projects). Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 19, 2023 Share Posted January 19, 2023 47 minutes ago, DrVenkman said: How did you get hold of a HOKEY, Jesse? I have never received an email from Fred with the option of purchasing one (or more - I plan on at least a couple for various projects). He sold me a standalone HOKEY at PRGE. That is the one I have in my Mateos cart for testing. The other HOKEY was in the Concerto I also bought from Fred at PRGE. 1 Quote Link to comment Share on other sites More sharing options...
+batari Posted January 20, 2023 Share Posted January 20, 2023 6 hours ago, -^CrossBow^- said: He sold me a standalone HOKEY at PRGE. That is the one I have in my Mateos cart for testing. The other HOKEY was in the Concerto I also bought from Fred at PRGE. It's important to note that the design philosophy of HOKEY Basic is as a low-cost POKEY-compatible sound chip for Atari 7800 homebrew games. It was not specifically designed as a direct drop-in POKEY replacement on existing boards, though it is possible to use it for that purpose. Thought I’d add a sentence here. I think it’s worth using a HOKEY over a POKEY or over other alternatives because HOKEY is being used for homebrews and those other alternatives are not. And HOKEY will likely evolve features that the other approaches will not be capable of replicating and this includes POKEY replacements as well as flashcarts that lack a real POKEY socket. The simplest explanation is that a real POKEY needs "help" in the form of output circuitry to actually produce any sound. HOKEY does not need any help as all of the output circuitry, along with an audio filter is on the HOKEY itself. This makes for easiest and lowest-cost building of homebrew games. The very first HOKEYs that went out in October had about 10 dB lower volume than a real POKEY, but only a few went out. Concertos sold since November with a socketed Concerto, or those who bought a HOKEY to retrofit into an existing Concerto, currently will be about 3 dB lower than a real POKEY. Concertos with soldered-on HOKEY, however, have the full volume of a real POKEY. It's easy to do when you don't have to support a real POKEY. It is possible to modify any Concerto to have full output volume, but it needs to be reverted if you want to use a real POKEY. So to give people the flexibility to be able to use a HOKEY or a POKEY on your Concerto, what I did was create two flavors of HOKEY Basic. One is designed for new installations, and one is designed as a retrofit for an existing POKEY setup. The New Installation Basic HOKEY has the original output circuitry, and the retrofit has modified output circuitry. The retrofit version has a higher base volume than the new installation version, to overcome the POKEY output circuitry which then lowers the volume. The new installation version has a lower base volume over the retrofit version, but with higher output quality. So, in order to get that 3 dB back, if you have a socketed Concerto... as said you can perform a mod to your Concerto, or you can wait for firmware updates. Or both. I'll explain the various Concerto/HOKEY combinations here: Spoiler So, a summary of the various Concerto/HOKEY combinations out there. The October Concertos had a New installation Basic HOKEY on the existing POKEY setup. This work but the volume will be 10 dB lower. This is what happened with the first few HOKEYs that went out on Concertos. If you buy a HOKEY Basic from the Concerto email list, you will get the retrofit version (see above). This only loses about 3 dB overall after going through POKEY's output circuit. If you buy a new Concerto with a socketed HOKEY Basic installed (since November), I set up the Concerto itself for a New installation HOKEY. The Concertos are also set up with an option for an easy fallback to a real POKEY if you want to use one instead. If you buy a Concerto with a soldered-in HOKEY Basic installed, there is no provision for a POKEY so volume level is already ideal on these. Here is a simple technical explanation of why the volume is lower in some cases, and how this may be corrected: Spoiler POKEY requires external circuitry at its output, and HOKEY has it on the board itself. POKEY's external circuitry is not designed for HOKEY and lowers HOKEY's output volume more than necessary. HOKEY supports dual POKEY, and to support two POKEYs without audio distortion, it was necessary to lower the output volume of each individual core by around 3 dB. The output profile of a real POKEY starts to drop off at around 35% of its max output level, flattening significantly by 50%, but HOKEY is linear throughout the entire range. Allowing the full range also meant lowering the base volume to avoid distortion. Ways to improve this with future firmware: Detect use of single vs. dual POKEY and use a higher volume level for a single core. Adjust the output profile to more closely match a POKEY so the base volume may be increased. Examine real POKEY tunes and record the maximum amplitude used in practice so the base output level can be increased to just below the point of distortion Allow adjustable base volume to match user preferences The above refers to HOKEY Basic with firmware 1.00 (which is all HOKEYs shipped before today). I've already done some of this for version 1.01 and it's up 1 dB over 1.00. The goal is to chip away that full 3 dB. There isn't yet a user-friendly way to update your existing HOKEY, but that will be available in time. With the various changes and with different configurations of HOKEY, in some cases there may eventually be the opposite problem where HOKEY is too loud and should be adjusted down. Here is a slightly more complex technical explanation: Spoiler A real POKEY uses open-drain NMOS transistors on its output, which cannot produce an output voltage on their own. So a real POKEY requires output resistors (1k pull-up and 12k series) on the board to produce the correct voltage and current. HOKEY does not need a pull-up at all, and ideally should not have one. HOKEY also has an audio filter on its output, and the POKEY resistors act together with this filter to attenuate HOKEY's output. I experimented with adding an amplifier circuit at the output of HOKEY to overcome the POKEY resistors that attenuate the volume. I found that to be a poor solution to add a complex circuit when it and the POKEY resistors would just cancel each other out. Better to eliminate both! That way I would be able to sell HOKEYs to homebrewers for as low as $7.50 each in quantity. A last salient point: If you have an existing production Concerto and bought a HOKEY to retrofit into your cart, there is a simple mod you can do that will both improve the output by about 1.5 dB, and improve the quality of the audio filter slightly. That is in the spoiler below: Spoiler Note: again, this mod is only for existing, production Concertos, and not for pre-production versions, or for most Concertos that you purchased with an installed socketed HOKEY (they already have a similar mod.) Just install a wire between the two through-hole points, circled in red. If you need to revert to a POKEY, you just need to remove or clip the wire. 8 Quote Link to comment Share on other sites More sharing options...
MaliciousCarp Posted January 20, 2023 Author Share Posted January 20, 2023 Thanks so much for the great explanation- I'll have to experiment this weekend! Quote Link to comment Share on other sites More sharing options...
Bratwurst Posted January 20, 2023 Share Posted January 20, 2023 @batari: I bought a pre-production Concerto with a socket back in 2021. I just received my HOKEY that I ordered through the emailed link for early Concerto buyers who had pre-ordered. What do I need to do, if anything, to get the volume on par with the original POKEY output? Thank you for your clarification. Quote Link to comment Share on other sites More sharing options...
+batari Posted January 20, 2023 Share Posted January 20, 2023 4 hours ago, Bratwurst said: @batari: I bought a pre-production Concerto with a socket back in 2021. I just received my HOKEY that I ordered through the emailed link for early Concerto buyers who had pre-ordered. What do I need to do, if anything, to get the volume on par with the original POKEY output? Thank you for your clarification. If you have a pre-production cart and bought a "retrofit" HOKEY, the easiest thing to do is wait for a firmware update that can increase the volume. However, if you are comfortable with surface mount soldering: In other words, remove R14, then remove R15, and move it to where R14 was, and leave R15 unpopulated. Note that the Concerto pictured here is already modified, as R15 was never attached. The layout is the same on 2016 (purple) Concerto boards as well. Due to the relative difficulty of this mod, it is not recommended for most, unless you are skilled with SMT soldering. But if you do this, the HOKEY will be full volume. 1 1 Quote Link to comment Share on other sites More sharing options...
+Karl G Posted January 20, 2023 Share Posted January 20, 2023 Put your R14 in... Put your R14 out... Put your R14 in...and shake it all about! (sorry...couldn't resist) 9 Quote Link to comment Share on other sites More sharing options...
madmax_2069 Posted January 21, 2023 Share Posted January 21, 2023 1 hour ago, Karl G said: Put your R14 in... Put your R14 out... Put your R14 in...and shake it all about! (sorry...couldn't resist) You do the Hokey Pokey........ Hey wait a minute 2 Quote Link to comment Share on other sites More sharing options...
Bratwurst Posted January 28, 2023 Share Posted January 28, 2023 On 1/20/2023 at 3:46 PM, batari said: Due to the relative difficulty of this mod, it is not recommended for most, unless you are skilled with SMT soldering. But if you do this, the HOKEY will be full volume. I just performed this modification (removing R15 and R14, and placing R15 on R14) and the volume of the HOKEY chip was still disappointingly low. Compared to the POKEY in my original Ballblazer cart the HOKEY in the Concerto feels like it's 5 dB quieter playing the special Concerto Ballblazer hack - Ballblazer (NTSC) (Concerto HOKEY Basic) (20221019) Anything else I could do? Quote Link to comment Share on other sites More sharing options...
+batari Posted January 28, 2023 Share Posted January 28, 2023 2 hours ago, Bratwurst said: I just performed this modification (removing R15 and R14, and placing R15 on R14) and the volume of the HOKEY chip was still disappointingly low. Compared to the POKEY in my original Ballblazer cart the HOKEY in the Concerto feels like it's 5 dB quieter playing the special Concerto Ballblazer hack - Ballblazer (NTSC) (Concerto HOKEY Basic) (20221019) Anything else I could do? Yes, you can short R14. In my experience, though, it makes it louder than a POKEY. Just curious, do you have an AV mod on your console? I am doing all of my measurements with RF, but it is possible that different AV mods will combine channels in different ways and I have not experimented with the effects of this. Quote Link to comment Share on other sites More sharing options...
Bratwurst Posted January 28, 2023 Share Posted January 28, 2023 I'll give that a try soon and let you know. In fact if you'd like I can do some experimenting on my end with different resistor values for R14 I could do that too. I do have the UAV Brewing Academy s-video mod, which I installed following -^CrossBow^-'s method illustrated at https://www.youtube.com/watch?v=t7b3JXgZzcw Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 28, 2023 Share Posted January 28, 2023 2 hours ago, Bratwurst said: I'll give that a try soon and let you know. In fact if you'd like I can do some experimenting on my end with different resistor values for R14 I could do that too. I do have the UAV Brewing Academy s-video mod, which I installed following -^CrossBow^-'s method illustrated at https://www.youtube.com/watch?v=t7b3JXgZzcw @batari So if he followed that guide, then he simply took the original resistors on the 7800 mainboard and tied them together with a cap for filtering before running it to the RCAs. That follows the original Atari circuit. Also I took a look at my HOKEY setup on my Mateos that I modified to get the HOKEY louder and what I did was to modify the Mateos cart itself that had a resistor on the external audio line and jump it. That brought the HOKEY to within just a few dB of the TIA and they are nearly the same at that point. But again, I modified the Mateos cart and not the HOKEY itself in that case. Quote Link to comment Share on other sites More sharing options...
+batari Posted January 28, 2023 Share Posted January 28, 2023 5 hours ago, -^CrossBow^- said: @batari So if he followed that guide, then he simply took the original resistors on the 7800 mainboard and tied them together with a cap for filtering before running it to the RCAs. That follows the original Atari circuit. Also I took a look at my HOKEY setup on my Mateos that I modified to get the HOKEY louder and what I did was to modify the Mateos cart itself that had a resistor on the external audio line and jump it. That brought the HOKEY to within just a few dB of the TIA and they are nearly the same at that point. But again, I modified the Mateos cart and not the HOKEY itself in that case. Could be the cap. I already use a cap for filtering HOKEY output but a second filter cap in the circuit could cause a steeper drop off in frequency response. To make this situation better, shorting R14 should help. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 28, 2023 Share Posted January 28, 2023 9 minutes ago, batari said: Could be the cap. I already use a cap for filtering HOKEY output but a second filter cap in the circuit could cause a steeper drop off in frequency response. To make this situation better, shorting R14 should help. But that doesn't make sense since the original circuit had the audio going through a pair of poly caps before going to the RF modulator. So by that statement even a stock 7800 would have this issue? Quote Link to comment Share on other sites More sharing options...
+batari Posted January 29, 2023 Share Posted January 29, 2023 6 hours ago, -^CrossBow^- said: But that doesn't make sense since the original circuit had the audio going through a pair of poly caps before going to the RF modulator. So by that statement even a stock 7800 would have this issue? From the schematics, PAL has one combined output while NTSC has two channels combined into one so perhaps that is where the difference lies. Quote Link to comment Share on other sites More sharing options...
RickR Posted January 30, 2023 Share Posted January 30, 2023 (edited) I also have a pre-production Concerto cart. I just today received a HOKEY chip. My Concerto had a POKEY in it already that worked fine. But the HOKEY has issues. I don't mind the lower sound volume, but Ballblazer has hisses and pops with the HOKEY. I tried reseating the chip, but the sound is the same. Pops and glitchy. Current Concerto firmware is 0.94a Is there a firmware update for the Concerto I should install to help with this? I'm not sure what to do other than put the POKEY back in. Maybe I got a defective HOKEY? Any advice would be greatly appreciated. Thanks. Edited January 30, 2023 by RickR 1 Quote Link to comment Share on other sites More sharing options...
Bratwurst Posted January 30, 2023 Share Posted January 30, 2023 On 1/28/2023 at 12:01 AM, batari said: Yes, you can short R14. In my experience, though, it makes it louder than a POKEY. I managed to get around to this tonight, removing R14 and shorting it with a solder bridge- HOKEY volume is a lot better now. I'd still say it was lower than an original POKEY's output by a couple of decibels but it managed to compete admirably with the TIA sound effects in Commando so I'm content for now. 2 Quote Link to comment Share on other sites More sharing options...
+batari Posted January 30, 2023 Share Posted January 30, 2023 3 hours ago, RickR said: I also have a pre-production Concerto cart. I just today received a HOKEY chip. My Concerto had a POKEY in it already that worked fine. But the HOKEY has issues. I don't mind the lower sound volume, but Ballblazer has hisses and pops with the HOKEY. I tried reseating the chip, but the sound is the same. Pops and glitchy. Current Concerto firmware is 0.94a Is there a firmware update for the Concerto I should install to help with this? I'm not sure what to do other than put the POKEY back in. Maybe I got a defective HOKEY? Any advice would be greatly appreciated. Thanks. Might be defective. I'll send a PM so I can get a replacement out to you. 1 Quote Link to comment Share on other sites More sharing options...
RickR Posted February 9, 2023 Share Posted February 9, 2023 On 1/29/2023 at 8:28 PM, batari said: Might be defective. I'll send a PM so I can get a replacement out to you. The replacement works perfectly. Thank you. 3 Quote Link to comment Share on other sites More sharing options...
CommodoreDecker Posted April 23, 2023 Share Posted April 23, 2023 On 1/29/2023 at 10:11 PM, Bratwurst said: I managed to get around to this tonight, removing R14 and shorting it with a solder bridge- HOKEY volume is a lot better now. I'd still say it was lower than an original POKEY's output by a couple of decibels but it managed to compete admirably with the TIA sound effects in Commando so I'm content for now. This is awesome news; thanks for sharing! I will look up R14 shortly. I have a 7800 w/ AV output mod that was always quieter for POKEY sounds, and R14 sounds like that may be the cause. (Also, after swapping my old failing receiver for a new one, it also does filtering and rendering any POKEY sound impossible or near-so to hear.) Quote Link to comment Share on other sites More sharing options...
TJ76 Posted July 6, 2023 Share Posted July 6, 2023 On 2/9/2023 at 12:15 AM, RickR said: The replacement works perfectly. Thank you. I've recently received my Concerto with Hokey, and experiencing what sounds like may be the same kind of hisses and pops for Ball Blazer and constant noise in background when playing POKEY (Sample) (20140301).a78 (Daisy Bell Test) from atari-7800-roms-ultra on internet archive. Commando sounds ok, albeit with Pokey music a fair bit lower than TIA volume, and reading above about R14 bridge solution, however wondering if I have a bigger problem here? Do you think I may have a defective Hokey also, is this common, or is there anything else I could perhaps test here? I'm using an AV mod as detailed here (7800 PAL revision) , with Pokey audio taken from Right of R33. https://vintagegamingandmore.com/pal/ Thanks for any suggestions. 1 Quote Link to comment Share on other sites More sharing options...
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