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Messages - joecool85

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1
Amplifier Discussion / Re: VOX Mini 3.. No speaker output
« on: June 15, 2021, 08:46:53 PM »
Here's a copy of the installation instructions but I must stress I don't make them anymore and don't have any!

Fantastic job, looks really professional!  No worries you don't make them anymore, still a very interesting share!

2
Amplifier Discussion / Re: VOX Mini 3.. No speaker output
« on: June 14, 2021, 04:21:48 PM »
I had forgotten all about these.  Midibob, if you don't mind sharing a picture of the board and maybe some info, I'd love to have it here on this forum!

3
It seems to be all about pedals this year, and here is more of the same...sort of.

Chaos Audio Stratus is running a Kickstarter for their new pedal that they claim will be the last guitar pedal you will ever need.  Controlled by your smart phone, this pedal is all digital and only has one physical knob.  A winner?  I doubt it, but interesting none the less.

Next we have the TC Electronic Zeus Drive.  In their now-familiar stompbox size, they are offering for $60 USD a great little "Klon style" overdrive.  I think I may need to play with this one in person!

https://www.gearnews.com/chaos-audio-stratus-the-last-guitar-pedal-youll-ever-need/

https://www.gearnews.com/tc-electronic-zeus-drive-launches-with-2000-units-on-offer-using-germanium-diodes/

4
Honey Amp / Re: Just got the kit this weekend
« on: June 02, 2021, 09:32:04 AM »
Oh, also, Call me ignorant but . . .
am I supposed to jumper the H1 and H2 gain pads? It sounds pretty good without it, but am I supposed to? What is the purpose of those points?

H1 and H2 are the gain control pins for the LM386.  Leaving them open sets the LM386 at a gain of 20.  Tying them together with a capacitor (or quite frankly, just jumpering them) will bring the gain to 200.  If you want to play with it, I suggest soldering in a couple sockets so you can try things.  By design, you don't need to do anything with them.  That said, I tried to build this board with tinkering/modification in mind.  For this reason, I added in C0 and R0 if you want to get rid of the normal preamp section and just have an input buffer.  I also have H1 and H2 for the gain control of the power amp section.

5
Amplifier Discussion / Re: Acoustic 370 Output Level Issue
« on: May 25, 2021, 08:36:17 AM »
Post Mortem - the amp is working again and the possible root cause was that one of the output transistor sockets failed and Q307 base was disconnected. I didn't see this till way later and the multiple component swaps resulted in the wrong resistor value was used for R314 (feedback path). One the socket was repaired and R314 replaced the amp is working as designed. Thanks for the help.

Thanks for the follow-up!

6
Honey Amp / Re: Just got the kit this weekend
« on: May 24, 2021, 12:54:36 PM »
I put it together this weekend and it seems to be working just fine. I can't get the aux or headphone jacks to work, but the amp drives a 1x12 just fine. I'm stuggling with a cold solder joint in the power supply and one in the speaker output. I've tried resoldering them, but it doesn't seem to be working well. I'm going to try soldering it from the other side of the board later this week.
I was thinking of installing it in a 1590c enclosure, but does anyone have other suggested enclosures for these little amp projects?

If you can show some pictures of your board (both sides) we might be able to give some tips on where you are having trouble.  Also, what are you using for solder?  And your soldering iron?  Could be tip size or shape causing issues as well.

Regarding the enclosure, the sky is the limit.  I put mine into an Earl Grey tea tin.  Ideally I like to use metal enclosures to help with reducing hum/static/noise, but honestly, you could put this into most anything and have it function fine.  I like finding interesting enclosures for things.  I built a tiny amp into a wooden "treasure chest" from a craft store while in college - that was fun and looked pretty cool.

7
Honey Amp / Re: Power supply suggestions
« on: May 21, 2021, 11:36:20 AM »
Also, if you are looking at only using this clean, you might want to consider running this without the overdrive circuit at the front.  The board is set up to be able to run the MPSA13 as a buffer in front of the LM386 if so desired.  I had thought this would mostly be for a bassist or keyboard etc, but could be used for clean guitar for sure.  The notes for "clean buffer mode" are on the bottom of the schematic.

8
Honey Amp / Re: Power supply suggestions
« on: May 21, 2021, 10:33:58 AM »
To get the most clean sound out of it you will want 12v or so.  I use a 12v SLA that I have hooked up to solar for charging my cell phones and other devices at home.  While it works well, clean power is limited on this little guy.  The best clean sounds can be had with higher voltage and a 16 ohm speaker with high SPL ratings. 

The 4" speaker sold with the kit is rated for 90db @ 1w.  This is fantastic for such a small speaker (most this size are between 83 and 86db, sometimes lower).  Large guitar speakers can be significantly higher than this though.  Many 12" speakers are around 102db @ 1w.  This means it would be over twice as loud for the same wattage going into the speaker.  So, for max volume, a 12" guitar speaker at 16 ohms, rated at 102db/w and using a power supply of 16v power supply (yielding 1.2w clean power) would give you 103.6db at 3'.  To put this in perspective, your current situation running on 9v with an 8 ohm load (yielding 0.5w clean) on the stock 90db/w speaker gives only 87.8db at 3'.

Your options on the stock speaker are to increase power to 12v which does give you a little bit more headroom (a total of 0.6w clean or so) and then you can play with increasing the gain on the LM386.  I think you'll find though that given that small speaker, that's about as loud as you will get clean.  If you find a way though, please share!  I love being wrong on this kind of thing!

9
Wish they’d re-release the Heavy Metal pedal. I left mine in a rehearsal warehouse in 1988. That box in front of my Princeton was amazing (still have the silverface). They are stupid expensive on reverb.

Apparently this is already in the works: https://www.guitarworld.com/news/boss-confirms-an-hm-2-heavy-metal-reissue-is-in-the-works

10
Boss is commemorating 40 years of the SD-1 Super Overdrive and 30 years of the MT-2 Metal Zone.  Say what you will about these pedals, but you can't argue they have staying power!  Plus the black looks killer!

You pay a $10 premium for the new paint bringing the MSRP for the SD-1 is $59.99 USD, and the MT-2 in at $112.99 USD.

https://www.gearnews.com/boss-commemorates-two-milestones-with-all-black-anniversary-mt2-and-sd1-pedals/

11
Honey Amp / Re: Just got the kit this weekend
« on: May 17, 2021, 02:49:32 PM »
I just received my kit, but I had a very busy weekend and didn't have time to work on it. I am planning to start assembling it this week and I will try to document the build on youtube. I probably won't upload anything until the amp is fully assembled and operational though.
Anyhow, I'm excited! Really looking forward to this!
 :dbtu:

Sounds great, I'm looking forward to seeing how it comes out!  :tu:

12
Amplifier Discussion / Re: Vox Pathfinder 10 as a modding platform
« on: May 12, 2021, 02:41:17 PM »
Great job!  I love modding these small amps, plus the Vox Pathfinder 10 looks mint!

13
Amplifier Discussion / Re: Thunderfunk with Dead Power Amp Board
« on: May 04, 2021, 11:50:47 AM »
Like most of these modules, the output is balanced. That means you can't ground one side, and you shouldn't use phone type plugs because there will be dangerous Voltages on the metal shells.

There is no good way to drop Voltages to what you need. You can burn several hundred watts via analog means, or build a switching regulator :(

Good points, and all the more reason to not use 1/4" jacks for speaker connections.  Time to use Speakon connectors.  It's been 25+ years, time for the industry to transition!

Regarding the voltages, you could use a DC/DC converter, but honestly I would just build out a new PSU for the power amp.  Leave the existing for the preamp if you'd like though.

**edit**
I just looked at the datasheet you shared.  The +/-12v is for input voltage, IE signal.  Your preamp will provide that without issue I would guess.  You do need about 75v DC for the PSU though.  Looking at Parts Express, it seems that the board you linked is for use only to add on to another "ICE" board.  They recommend using this one with it's built in PSU for $312 USD: https://www.parts-express.com/ICEpower-500ASP-Class-D-Audio-Amplifier-with-Power-Supply-Module-1-x-500W-326-204

14
Amplifier Discussion / Re: Chipamp kit LM1875 PDF?
« on: May 04, 2021, 11:44:45 AM »
Hey everyone. I was a member here way back when this forum began and was lucky enough to receive a couple of chipamp.com kits from Brian and this site. The LM3886 and the stereo LM1875.

I assembled the LM3886 kit but never got around to testing it because I couldn't afford the transformer and never assembled the LM1875 kit. Found them the other day and would love to finish them up. The LM3886 I reversed engineered it but would still like to check. The LM1875 I have no reference for.

If anybody has the PDF of the instructions that isn't a dead link I would much appreciate it.

Cheers

Here you go: https://www.ssguitar.com/index.php?topic=5031.0

15
Schematics and Layouts / Chipamp.com schematics and manuals
« on: May 04, 2021, 11:44:22 AM »
I've had a few people ask about these so I figured I would share them.  Attached are the manuals (with schematics) for the LM1875 and LM3886 kits BrianGT sold at Chipamp.com for a long time.

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