ramtubes
Responses from ramtubes
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9Are you aware that the secondary capacitance of this transformer is 800 pf and the input capacitance of the speaker panel is many times lower? If I multiply that times turns ratio squared i get a primary load of 45 Microfarads. For the tran... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 Each Quad has its own mono block. Two Quads facing ahead, and two Quads at one radian angles, facing in. A bit like one of Walker's experiments. Think of two sides of a hexagon on the left, mirror image on the right. And two at the back ... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. I have bought a set of 4 Gold Lion (Russian) KT-66's for use in my pair of Heath W5's. $35 a tube! Originals sell for $200+ a tube (UK). They sure do look real nice! I still have the original US Tungsol 5881's in use. I wonder if the Russian one... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @tomic601 My question is what tube testers are you recommending at sane portable prices.. The B&K Dynajet series is fine and still under $100 or less on eBay. The 601 is the one I have. Although I have the big Hickok I find it heavy and slow ... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @quincy I have always wondered if vacuum tube technology was abandoned prematurely (for solid state), and never fully exploited to its full potential? Vacuum tubes were not abandoned but slowly pushed aside. However the majority of reciever man... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 I see you have jumped on the bandwagon of expensive parts. I have not yet found them to be superior and they are costly and often fragile. Those resistors especially. I dont see the benefit.As far as dialectric, i understand it well. Let m... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @roberjerman So Roger: new production tubes from our old Cold War rivals. Can the Russians really make and sell quality tubes at such low prices? A quartet of 12AX7's for $18 (shipping free!). We did that ourselves back 50-60 years ago. But that ... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. I still prefer US, European or Japanese vintage production over the new stuff! Is a 1980s RM-9 in good working condition vintage enough? :) They just going like the Energizer Bunny | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 @atmasphere Actually this is pretty common with bipolars. They can get into a phenomena known as 'thermal runaway' if this is not well controlled. Ralph, did you perhaps mis-read this. He said the idle goes down not up as the amp warms... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @bdp24 Roger, here’s a question about light loading with the RM-200 Mk.2 amp: With a loudspeaker given a nominal 8 ohm load rating by it’s designer/manufacturer (it measures between 10 and 20 ohms from 20Hz to 20kHz save for the 60Hz-180Hz band,... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 I would use a dual trace scope, make sure the two channels have identical gain, use one emitter resistor on channel 1, call that the reference. Then use channel 2 to see how the others (one at a time) match up at various power levels. I w... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 Thanks for the nod ... I guess the takeaway is, "Don't be so lazy. Match HFE at operating temperature and current." Thanks! Have you measured the idle current of each transistor at operating temp in the amplifier? You of course know jus... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @geek101 @ramtubes with Class D switching freq over 450/500 KHz these days do you still think output filtering is an issue?. How do I educate more about this ?. If the issue of filtering not a function of switching freq please correct me. Thanks... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @enobenetto I own your RM-10mkii, which is a mysteriously addictive amp. How did you approach low-frequency response? I ask because the bass the amp produces is punchier than any 100-watt solid state I've owned.I have zero knowledge of electroni... | |
| Does anyone care to ask an amplifier designer a technical question? My door is open. @terry9 In case you are wondering, the 25V rails are to accommodate Quad ESL's. With 75:1 step up transformers (Plitron), the amps can only punch the panels to 3750V, exactly half the level which engages the protection circuit. So I can bypass t... |