I just wanted to touch on the subject topic this afternoon. I have recently been helping out an individual who is assembling an amplifier with a purchased PCB. And he’s having a few issues.
It really doesn’t matter what are his specific build issues. It is sufficient to say that in a few minutes I discovered two issues with his board and schematic. One that prevents the amp from functioning at all, and another that can cause poor performance and early tube failure. Like many before him, he purchased what looked like a nice PCB off of eBay with the name of a reputable manufacturer attached.
Now I see nothing wrong with buying finished amps, complete amp kits, bare PCBs, or just parts for a schematic you’ve acquired or designed yourself. But there does need to be a word of caution. Before spending your hard earned dollars on any of the aforementioned approaches, please do your research. The audio world, and especially the tube audio world, is full of grifters, frauds, thieves, and other assorted miscreants.
If your desire is a nice tube amplifier for listening to music, a little bit of research about from whom you buy is in order. What is the seller’s history? Do they support their products? Are they available for consultations? Do they have references? Not just “reviews” (like you might find on an internet website) but real “references”? References are actual people you can talk to or email and ask them about their experiences. What is their reputation? Even positive answers to all these questions may not prevent a bad experience, but they will certainly minimize the possibility that you won’t be satisfied.
I would like to illustrate with what I believe are the two ends of the spectrum. At the bad end there are the “flash in the pan” sales outfits (usually on a site like eBay, but not always). These guys show up with a quick website, or as a seller on an auction site. Likely you can’t find any real people who’ve done business with them, but their web/sales sites always claim thousands of satisfied customers. They typically like to attach (or infer) the participation of some well known manufacturer or producer. And the products they sell are limited. There are hundreds of these types of sellers on eBay selling bare PCBs, boutique components, or even just schematics. All are supposedly the “real” part or “based on” something that’s produced by some high end manufacturer.
When you buy from one of these sites, it is impossible to know what you are really getting. Some sell well designed equipment at reasonable prices. However most do not. And once they have your money, it may be impossible to get any support out of them. And in many instances they are gone in few months only to be replaced by a different website or ebay seller offering similar items. These are the grifters and miscreants mentioned above. It is usually better to avoid these people at all costs.
At the other end of the spectrum are two types of sellers. One is the big name companies, which have been in business for years, selling from their own websites and in speciality stores. These are the old guard of the vacuum tube audio industry. They have support lines, references, and transparent ordering. They are also likely very expensive. But here, usually for finished and tested equipment, you can’t go wrong. Unfortunately, many of these sellers are just too expensive for a lot of people just looking for that tube sound.
The other type of seller at the good end of the spectrum are sellers like Oddwatt audio. They sell a complete line of fine quality tube audio amplifiers and preamplifiers for pretty reasonable prices. But here’s the real difference, their customer (and non-customer) support is impeccable! If you have a question about an amplifier, or a kit, they will support you until you are completely satisfied. And there are no secrets. Schematics are published, part sources are known, all questions about the design and build are on the table. What this really means is that you can be assured that if you run into issues, you have a way to get those issues resolved.
And along this spectrum of audio sellers and information sources are numerous other places to find what you may want or need. My only request is that before you buy, please do some research. No only on the product you’re acquiring, but on what you think you really want. Is the high end 300B amp your real desire or is someone else telling you that it is? Do you really need 50W of output power, or maybe jsut a few watts for quiet to moderate listening? It is really easy to get sucked into buying something that is a lot more than you truly want or need.
And please do a little price investigation. As a price example, right now for the Marblewood amplifier on this website, the Edcor iron is available for about $130 USD and the Hammond choke is ≈$25 from another seller. Less than $160 USD for all the iron for a complete stereo amplifier. All the other parts for the amplifier are maybe another $200. So all the parts and information for less than $400. If you are finding that the bill is two or three times that, then you probably need to be asking some more questions.
I don’t want to discourage anyone. But I know that the whole experience will be more enjoyable and much more fulfilling without any unnecessary headaches along the way.
Just some food for thought.