The Amp Garage

What's the difference between using one 220K for both plates or using one 220K for each plate? Each plate sees a 220K resistor in both cases....? 220K shared = each section sees 220K/2 = 110K. A shared plate R is a plate mixer : signals from both sections develop across it. Preview Posted: Mon Mar ...

I need to do the math to see what this does to the low pass and RF attenuation F3 is around 38 KHz or so unloaded and doesn't fall below 10 KHz with the volume down on a typical guitar. some gain reduction in the 1st stage of a lightning seems to be a good thing and reduces the fizzy, somewhat hars...

I'll have him try a new power cord.. Check grounding while you're at it. Could bad tubes cause this effect? Hmmm, not impossible but improbable. Also: I didn't quite get the early post, about 68K resistort, highpass etc. I know the components, but are there other values on the mentioned components,...

Doesn't that amp have a master volume? Since that amp has the post phase inverter master, it would seem that you can drive the PI hard by turning up the pre-gain and lower the MV. Yes the lightning has the phase cancelling MV with a 180 pF cap on the pot, at least that's how I do them. Part of the ...

The Jackson 648 is a dynamic emission tester, quite flexible and fast but far from sufficient for any half decent testing. I take thats a no, it can't be used for any meaningful kind of matching? Aside, I have noticed that on some amps, notably 18 watt TMB marshall based amps I think it was, unmatc...

Or use the unused triode as a cathode follower which warms up the tone and drops the gain a bit and works nicely with TMBs. Use the first triode pair for 2 channels and the extra triode makes a cathode follower. Using the first two triodes in parallel matchless style also lowers it's output impedanc...

It's up to the consumer to apply QC to new tubes. If they are bad, send them back to the Tube Depot and get your money back. Again, tube testers are of limited utility. They don't put your tubes into a realistic operating condition, so they don't tell you squat. The only way to get a good set of ne...

So much for my deductive powers, thanks guys!

Thanks, i need all i can get! If it sounds like it did before i'm going to build a new board with all new components and wire and get all new sockets. This one has been thru too much and i need it to be dependable. This was mainly my fault, but the slop factor has just made it too fragile to depend...

Could someone tell me if there are date codes on the new Sprague Atoms and if so, how to read them? Thanks for any help!

Avoid all the New Sensor EL84 types except the Sovtek EL84M, which is their military EL84 type. The RI Mullards sound okay, but they are far from being matched directly from NS. The Gold Lions, Tung Sol, Svetlanas, etc.; all crap! Relabeled, untested, Sovteks. There are small differences in constru...

Counterfeiting in communist countries has been a way of life for so long, it is just 2nd or 1st nature for entrepreneurs there. If you think about, in the USSR and PRC, they have been copying American goods, parts, and devices for many decades. They send spies to steal secrets, they reverse engineer...

I feel really stupid already, so go ahead and embarrass me some more. Obviously I am the only one who does not understand the economics of this.... Seems like it would cost more money and effort to buy, then insert a 330/200 cap inside of a 40/500 cap to the point where it looks legitimate, and nob...

Rick, This is surely unsettling. I am having a hard time believing this was purposeful on the Weber's part. Ted died last year and his son, T.A. has taken over. I woudln't hesitate to send that picture to him and ask him about it. You should not only ask for satisfaction, you should get it. I think...

Problem solved.