Project article in EPE

[Mark Hammer]

The current newstand issue of Everyday Practical Electronics has a message recorder project using the HK828 chip (enter "HK828 pdf" into your search engine to find datasheets).  The chip has fairly high capacity, and the project is geared at 45 seconds storage.  Looks pretty simple, and uses thru-hole parts.

Just figured I mention it for those of you who like experimenting with phone-message chips as loopers.

[Jasonmatthew911]

Hi Mark, I noticed that you made a 2W mini amp with LM380 and pre-amp stage as well...Someone posted your schematic in my thread that says: "LM380 guitar amp has a pulsating sound at high volume level only, how can I fix?"...I was wondering if you could check out everything written in that thread since I know you already have experience with building a miniamp and pre-amp section....I made a very similar project, with a 4580 pre-amp w/ clip on heatsink, just in case, going into an LM380 with it's recommended Staver V-7 copper heatsink, but I'm running on 18V/1A adapter instead of 12V...Mine works fine, except when the Volume pot and Gain pot are almost full, it starts motorboating....After trying many things, and knowing for a fact that the pre-amp stage and power amp stage work just fine on separate 18V power supplies...Someone told me that the power should go into the power stage first since it is current hungry and then into the pre-amp...I had it wired the other way around, power was going into pre amp stage first, I had also tried connecting so that the power supply fed them at the same time, in parallel, but motorboating continued at high levels...So now I will try what was recommended, of feeding the power stage first, which makes complete sense to me now...Can you tell me anything about all of this, since you have experience with something very similar to my project....Hope you can help, thanks.

[LP Hovercraft]

Thanks-I'll be having a look at that article, Mark!

[Mark Hammer]

Hi Mark, I noticed that you made a 2W mini amp with LM380 and pre-amp stage as well...Someone posted your schematic in my thread that says: "LM380 guitar amp has a pulsating sound at high volume level only, how can I fix?"...I was wondering if you could check out everything written in that thread since I know you already have experience with building a miniamp and pre-amp section....I made a very similar project, with a 4580 pre-amp w/ clip on heatsink, just in case, going into an LM380 with it's recommended Staver V-7 copper heatsink, but I'm running on 18V/1A adapter instead of 12V...Mine works fine, except when the Volume pot and Gain pot are almost full, it starts motorboating....After trying many things, and knowing for a fact that the pre-amp stage and power amp stage work just fine on separate 18V power supplies...Someone told me that the power should go into the power stage first since it is current hungry and then into the pre-amp...I had it wired the other way around, power was going into pre amp stage first, I had also tried connecting so that the power supply fed them at the same time, in parallel, but motorboating continued at high levels...So now I will try what was recommended, of feeding the power stage first, which makes complete sense to me now...Can you tell me anything about all of this, since you have experience with something very similar to my project....Hope you can help, thanks.

Sorry, a bit beyond me, I'm afraid.