Doorway single ended tube amp

The APPJ/ Miniwatt has been around for a number of years. I think I bought mine back in 2010 and she's still going strong. The new version has the tubes on top and transformers on bottom but it's essentially the same amp. You can often find these for around $100. To my ears it's SQ is comparable to my Dennis Had EL84 SE amp. It's power tubes are 6P1's and there are convertors on ebay that allow you to substitute different tubes.

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StevenZ

Active Member
Amazon has a couple versions for sale. Not sure the amperex logo is used with permission or is any indication of the performance?🤷‍♂️
Can’t beat the price and aesthetics though.
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I had the original and always thought it sounded good. The guy I sold it to still uses it daily. He's put it up against some pretty expensive competition and still really likes it.
 

Audionut

Next Round Is On Me
I had the original and always thought it sounded good. The guy I sold it to still uses it daily. He's put it up against some pretty expensive competition and still really likes it.
I’ve always wondered about an entry level unit like this, slightly modded to be a giant killer or just punch way above their cost. I read a little about a version with WE tubes which was much better than the China tube version.
 

StevenZ

Active Member
I’ve always wondered about an entry level unit like this, slightly modded to be a giant killer or just punch way above their cost. I read a little about a version with WE tubes which was much better than the China tube version.
They take well to quality tubes. I sold mine with NOS Mullard EL84 and NOS Mullard 12ax7. I'm not sure how much they can be modded since they're REALLY compact.
 
Here is another bargain amp that uses the same output tubes.


Since eBay links have a shelf life, the amp is a PCB that uses two 6P1 and one 6N1 tubes. The price with tubes and shipping was a whopping $23. It arrived in less than 2 weeks from China. The buyer will then need to add a power transformer, a small choke, output transformers, RCA jacks and binding posts. The tubes that came with my amp appear to be unused.

The actual amp I received differed from the description in two ways. The PCB board now has provisions to add the second diode pair for bridge rectification rather than by using a supplemental PCB. Additionally, the discrete components have been soldered to the underside of the PCB rather than on the side with the tube sockets. The second item makes it much easier to make a finished amp. There are several sellers of the same amp on eBay and Amazon, who knows which version of the amp you will get.

The standard Chinese tubes do not have a great reputation for sound. The Russian 6P1P-EV seems to be the preferred upgrade for the outputs. They are plentiful and cheap. The 6N1 does not have an exact Russian analog. The closest Western tube is the 6AQ8. It is plentiful but not really cheap. Fortunately I have a dozen or so US,UK,Holland,German and Japanese pulls.

I haven't completed the amp yet. I have been playing around with the layout with the parts I have in my stash. Once I settle on a layout I will make a Bottlehead type of top plate and proceed.

John
 

Thermionics

Post Whore In Training
Another option if you are into roll-your-own, you can build a DGSE-1 for pretty damn cheap ($15/ea. per output transformer, probably another $60 for a new Edcore 500VCT power transformer, four tube sockets, some capacitors, some resistors, a cake pan, and some tubes - 12AX7 driver, EL84 outputs, and either an octal or 6CA4 rectifier). I built one from scratch using a Hammond box for less than $150.
 
There are a couple of adaptors on ebay that allow substitutes for the 6P1. Here I'm using the big smokey 6v6 Ken-rads . I've had the three tube version but the four tube is better. Mine has a diode mod which Ed Schilling ( Hornshoppe ) did for me some years ago.

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Over the years the APPJ/Miniwatt has been used with a host of preamps and the added gain allows it to perform well with any number of speakers.

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