Buffered multiple, part 1: A Horst of a different color

I opened up the third of the kits I ordered recently, the horstronic. Buffered Multiple, and found a surprise: Surface mount resistors. I wasn’t expecting them. I’ve never worked with SMT parts, and maybe I will someday but today is not that day.

Here’s the story. Back in 2013 there was a forum discussion on buffered multiples and Dave Jones posted a schematic. In 2014 horstronic (a German named Horst, I think) came up with a circuit board and front panel for a modification of Jones’s design and started selling them; I think that was horstronic.’s first module.

Then in 2017 he redesigned the PCB and panel, calling it Buffmult 2.0. I guess it became 2.1 later. Mostly the circuit remained the same but he added a couple LEDs and associated components. He also changed the colors of the panel and circuit board, which justifies my post title. (NARRATOR: It does not.)

Version 1 was designed for through hole parts; you can see the board clearly in this photo. Horst’s prototype for Version 2 was also built with through hole parts, though the resistors were mounted vertically; this photo‘s not as clear but you can make that out. But the pads for the resistors and the ceramic capacitors are close enough together that you can instead use surface mount parts, as mentioned in the BOM.

horstronic. doesn’t make kits. They produce PCBs and front panels. American vendor Synthcube sells those, but also makes up and sells kits using the horstronic. PCBs and panels together with parts Synthcube sources and packages. Evidently with version 2 they decided to include SMT resistors… but through-hole ceramic capacitors, for whatever reason. Which is fine, no reason you can’t build that way.

But I didn’t realize that when I ordered. Honestly I wasn’t really thinking about it, but implicitly assumed through-hole parts since Synthcube didn’t mention SMT. That was a rookie mistake on my part, no question, and for the future I have to remember not make such an assumption. But I think it also was an error on Synthcube’s part not to say there were SMT parts in their description of the kit. On top of that, the bag was labeled “thru-hole kit”.

So I got a surprise.

On close examination there were more surprises to come. I realized there were some resistors from the BOM not present, and looked and noticed they were associated with the TL072 IC that controls the LEDs… and the TL072 wasn’t included in the kit either. Nor were the LEDs. Nor a couple of capacitors in the LED section. In fact, none of the parts that were added for Version 2 were included. Synthcube obviously had made this kit up using the Version 1 BOM.

And one more surprise. There should be six 10 pF capacitors, in either version. My kit had a bag whose label said six, but it contained only two capacitors. Presumably a one-time stuffing error.

I’m not going to tear into Synthcube. Mistakes happen, and sometimes happen in threes. But clearly this kit was not what I wanted. I still want to build this module, but I’m not going to pay for Synthcube to source my parts if I then have to go and source all the resistors, one of the capacitors, the LEDs, an IC, and an IC socket myself!

So the kit goes back. I requested an RMA to return it to Synthcube, and ordered from them the PCB, the front panel, the jacks, and the power cable.

From DigiKey I ordered all the rest of the parts, except the trimmer pots. There are six of them, and at DigiKey’s $2.41 each they constituted a major fraction of the parts cost. Instead I ordered them on eBay, and even ordering from an American seller and paying separate postage, the price was lower than DigiKey’s.

In fact, here’s the cost summary:

  • Full kit, from Synthcube: $49 regular price. With 15% off sale and free shipping, cost was $41.65. Being refunded.
  • PCB, panel, jacks, and power cable, from Synthcube: $20.61 regular price. With 20% off sale and not free shipping, cost was $21.73.
  • Trimmers, from eBay: $5.94. With shipping, cost was $10.75.
  • All other parts, from DigiKey: $12.65. With tax and shipping, cost was $19.49

Total cost: $51.97. Clearly not saving big money this way, and in fact just keeping the kit and ordering the extra parts from DigiKey might not have come out much different.

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