The Amp Garage

Wait until he figures out that the input to the power amp and the feedback waveforms are IN PHASE. Have your answer ready !

Nelson Pass designed a power amplifier that used a really expensive Jensen transformer.

Link: https://www.diyaudio.com/community/thre ... er.216616/

The transformer has four identical windings, you use two in series for the primary and one each for transistor drive.

Here's how it works: Pretend for a minute that both triodes have 100K plate resistors. The current source is 2mA. With no signal that current splits evenly between the two triodes so each gets 1mA and that 1mA creates a 100V drop in each plate resistor. A signal comes along and causes the current in...

Schematic looks like a four channel PA head.

Checkout the input stage to an 18 Watt Marshall. The low gain input jack drives one triode, the high gain input jack drives both triodes in parallel.

One problem with SMD is that good AUDIO quality capacitors are large. The temptation to use low quality ceramic capacitors is very strong because of their small size, low cost and availability.

I'm not super familiar with Common Mode input range for Op Amps, could you explain further? The biggest effect is that the output stops obeying the inputs. What you usually see is that the output suddenly slams the opposite rail instead of staying where it belongs according to one of the inputs bei...

Pot in the overdrive circuit is drawn incorrectly. Opamp plus and minus inputs are wrong pin numbers. The minus inputs are next to the output so you can easily make a voltage follower :) Do you know the gain equation for a non-inverting opamp ? That Plus One term means a replica of the input is adde...

To clean the switch contacts on an old Switchcraft type jack my high school electronics teacher recommended using a piece of paper from a grocery store bag. It is kind of rough, maybe use a drop of De-oxit on it to remove any light oxidation. One clown I know uses a circular wire brush designed to c...

I have Jason's address in Florida that I got when I sent him some money. I sent him a letter, I think in January asking him to reach out and get help with any difficulties he may be having. I got no response.

I noticed robotrobinette has the first three grounds going to HV CT and the last goes to his board mounted bus bar. Are there benefits to this versus all four going directly to same ground connection? Yes. If a cap's minus is going to a noisy ground, the B+ for that cap will be just as noisy. A qui...

What I don't like about the Weber layout is the four electrolytic filter caps on the little standup board. Where does it ground ? Not sure. Tying all the grounds of the four caps together is bad practice.

Most of my designs are single layer with eyelets for power transistors and any wires that go off board. I use turrets for most power resistors. Am I going to have to create components for any jumper wires required on a single layer design ? Am I going to have to create a new component every time the...

I'm not seeing a ground connection to the pots in your layout.

The 22nF cap connected to pin 2 of the phase inverter is needed because there is DC on that node. The gain of that power amp is pretty high because there is no global negative feedback so the extra stage is not needed. You will probably find that the Volume control is useful