The Amp Garage

Very Sexy! Love your rack mount enclosures of choice...some of the highest quality I've ever seen outside of military data center rack mount gear. Out of curiosity...have you measured the S/N ratio in any of these preamps at higher gain levels? I'm curious as to how much hum is getting induced into ...

Got a lot of "Popular Electronics" to read thru from the 60s & 70s :shock: https://deramp.com/swtpc.com/PopularElectronics/ Also looking up Barcus Berry schematics but I don't think I've come across anything good so far. That 2k pot is throwing me off as a usable level pot . Lowest I've seen is 10k...

Interesting... Gil, thanks for sharing. Obviously an Op-Amp variation on the Mono Dumbleator... The enclosure looks like something straight out of an old LM/Heeger catalog or perhaps Hammond from the 1980's. That color I've seen before on standard catalog vendor enclosures...Hammond for certain had ...

Jelle, A very sexy build...I love the combination of the uber-rare NOS parts you are using. The 121K Plates coupled with the 1.69K Cathode resistors a good strategy given the scarceness of the usual suspect values here. For me, I'd run 1.82K on the Cathodes but 1.69K is surely close enough and you o...

OK, so if you look at your chassis there will be pencil markings on it with a date (maybe multiple dates) and odds are they date to 1971...or early 1972. From what you describe you have the earliest incarnation of the Super 450 which uses a fiberglass tag board with well-type eyelets (Commonly found...

Some pix of the guts of your 450 will make it easy for me to tell you what version you have. The last generation (version) of this amp had a PCB for the Reverb and Vibrato controls that mounted on the back of the chassis face...actually, quite a sanitary setup and makes for a very fast and simple as...

There are no factory schematics for the various versions of the Plush Super 450 available. There were at least 3 different versions of the 450 circuit and Plush, in those days, were in fly-by-night mode and just trying to stay afloat with no internal engineering on the payroll. Plush was looking to ...

The Plush Super 450 Combo amp was introduced in 1971 and then died out in 1973 (Along with Plush as a company). Plush built 3-4 different variations on this model starting out with a tag board version, culminating in the last variation which uses a mixture of terminal strips and PCB's. Different var...

Yes, I have actually already done this with both a Traynor YBA-3 as well as the Plush copy (4000G) of the Traynor YBA-3. The YBA-3 is actually more like a 120 Watt RMS amp in all actuality. B+ is is right around 550VDC on the plates at idle and will not pull down very much under load. Traynor used H...

Charlie Wrote: Did Piher and Draloric manufacture resistors to a spec for Sprague? I have never have seen I resistor that looks exactly like a Q-Line Draloric that did not come out of a Q-Line package. The ones in Ampeg amps look close. The same with the Pihers. The endbells are not as pronounced o...

Charlie, A few more pix of Sprague Q-Line "Filmistor" 5% Resistors for your perusal. Pay close attention to the 1/2 Watt 1.2R's...note they are definitely not Pihers!!! You can see right on the packaging that their country of origin is Japan. I believe the reason for the different source has to do w...

Charlie Wrote: Gabe, I found this in my Piher bag. I ordered 1k8 NTE from a guy and this is what he sent me. Maybe this is the Q-Line little plastic box you mentioned? Hello Charlie, I would say yes...that looks to be an old Sprague "Filmistor" Q-Line plastic container. These were generally taped t...

Charlie Wrote: I was wondering if you know something about the Piher resistors that Dumble used. I have been told that there were several locations that made the resistors. The ones everyone has been getting on Ebay don't look the same as the ones I have seen in his amps and I have been told don't ...

Charlie Wrote: I am curious about your reference to MF6 on V2 and Dales(I assume the brown rn65c) on V1. All the amps I have seen that have Dales on V1 also have them on V2. Am I missing something? Maybe you mean the PI plates in the 2nd generation amps? Hello Charlie, you are not missing anything…...

Mr. dB Wrote: I wonder how much of this was due to selection and how much just availability? A great question and something I've contemplated quite a bit. I know that many of these parts were available during the 1970's and 1980's for positive in Southern California where the aerospace industry was...