290 is similar to the 250 and both have inputs for 0.5V and 1.5V sensitivity. 250 is rated at 0.5% harmonic and 0.1% intermodulation distortion at full rated output.
HH Scott Owners Thread
- Thread starter RS Steve
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That is generally true for tube amps, and it necessitates connecting to the appropriate tap of the output transformer. Just be aware, not sure about the 290 but the 250 has an unusual speaker connection where negative must be connected to "0", *not* "G".
trainbuftony
Electron Herder
In my experience the specs of the hh Scott stuff were highly inflated. 36 claimed watts from a pair of 7591s when in reality they do an honest 24...
Take it all with a grain of salt until you perform your own measurements.
Take it all with a grain of salt until you perform your own measurements.
This is true of many other vintage brands as well. Of course, they weren't nearly as deceptive as the little SS amps in the '70s that could output 500W (for two microseconds). That's when the FTC had to get involved.
Jack
Don't have a schematic of the 290 to be conclusive, but my guess would be that it's largely a similar design but revised slightly and adapted for stereo. Rated power is a little different and output transformers seem different, so where the 250 was claimed to be class A the 290 is probably more AB biased. 290 seems to use 12au7 driver rather than 12ax7 in the 250, perhaps for a little more current. But there isn't a lot of info or literature on the 290 out there so it's hard to be conclusive.
kvflyer
Super Member
I have had this early edition, 222D for decades. I bought it from a member of the old HH Scott forum when it was up and running. The walnut cabinet was on my Scott LT-112-B that I had assembled as a teenager, new. This amplifier was 100% original, including all of the American Radionics Ceracaps. By the time they were making this model, American Radionics had started using Mylar for the dielectric. I did measure the bias voltage on the 7189 tubes and it was low. The suspect was of course, the Siemens Selenium bridge. There was evidence that someone had been checking the bridge before because two wires were just tacked in place. I replaced it with a silicon bridge and retained the original 18ꭥ resistors because at 117 VAC input, the output from the bias supply was ~ -47.5 VDC. Various models of Scott amplifiers have similar voltages.
Controls were cleaned and it works well. The original 7189 Telefunken output tubes test just about NOS. The rectifier is HH Scott branded Mullard and the rest of the tubes are all Telefunken. This is one of my keepers...
Controls were cleaned and it works well. The original 7189 Telefunken output tubes test just about NOS. The rectifier is HH Scott branded Mullard and the rest of the tubes are all Telefunken. This is one of my keepers...
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Made a few detours on a recent road trip to pick up a Scott 299 console unit. Looked fairly original but on inspection, it's had 2 cans replaced with Cornell Dubilier (I like the gold covering) and only 1 of the Tele ECC83. Thankfully the 7189s test like new as does the Scott GZ34 and 6BL8s. A serious deep clean to chassis, switches, tube sockets, pots, etc, replaced a burnt resistor and a slow burn in with the variac - sounds surpisingly clean. The 100/100/10 caps are leaky and need replaced as does the rectifier and a few resistors. Both bass pots were seized, but one finally came back to life. Beautiful amp and while not as big sounding as my 340b, lots of mids and top end.
That is a reference cleaning job! Beautiful.
Fantastic to clean, Simichrome to polish. Takes a bit of time, esp around the components. I would use it on any lettering though.
Haven’t even tried the phono yet!
My latest Scott restoration is this 340-B that was missing all its tubes and bottom cover. I gave it a complete restoration, and added two more test points so all output tubes can be measured for bias separately. It turned out real nice, but still need to fabricate a bottom cover for it. Most likely will use perforated metal screen that's thick and sturdy enough.
