Electro Harmonix LPB1 1972
This little bugger is a 1972 version of Electro Harmonics LPB-1. LPB meaning Linear Power Booster. It's been on production from 1969 to this day, so over 50 years. In that time scale my unit is relatively early one. The effect pedal (or "effects unit") has changed very little over the decades. Although the original floor pedal was called LPB-2. LPB-1 was a "plug-in to amp" or "plug-in to guitar" unit. This is not very practical thing, and I got this "just because", but I still like it alot for some reason.
LPB is a very simple small one transistor amplifier. It's so called text book circuit, and thus it's also easy to replicate and modify. However I don't recommend modifying these original units. As you can see in the gut shot, build quality is crap. And BTW be warned, these seems to be mainly positive ground circuits. Electro Harmonics sometimes did weird things like that. Connect your red battery lead to ground and the black lead to the switch. But that's just because at that time they had aquired cheap batch of PNP-transistors. If you build one for yourself, use NPN-transistor and negative ground.
We are very lucky to have modern PCB technology, as it improves the quality of electronics a considerable amount. Even the most inexpensive Chinese pedals are waaaaay more reliable than this blob of unskilled solder labour. If this represents "made in USA" quality in the 70s, no wonder Japanese manufacturers took over.
I got curious. As I said LPB is very simple, so there must be clones out there. Internet has, but how about the time before the digital age. When I was looking through some old magazines I found Elementary Electronics march/april issue of 1980... That's it! A clear clone of LPB. It's not 100% same, but it's so close it's obvious. Is this the earliest clone of commercial effects unit? Hell no, but it's still interesting to find such close match. For example fuzz circuits of these magazines are usually bad. And by bad I mean UTTER SHIT. No fuzz face or tone bender clones there!
After all this, I do like this booster because it's so basic. I might build my own plug-in version some day, but not just yet. I have collected some material, including the (apparently) f*cking expensive original 2N5133 transistor. I have four of these transistors, so it's either four LPBs or one Big Muff.