bremen

I love the "free B+". I did that for my Fenderpeg-Elliott. A dry joint or dried up cap in there would be another candidate for the cause of the BZZZZZZZ

Thanks, el Dooderino! I played in a band with a guitarist used a Valve State, I did enjoy its crunchy goodness.

Gday I'm about to have this combo delivered for me to repair. Fault is an intermittent very loud 100Hz buzz. Most likely a dry joint on a reservoir cap. But just in case it's not that simple, anyone got a schematic? Cheers

Another effective variation of that is a pcb drill bit. Heat the pad, push the drill through the hole while the solders melted, then spin the drill bereeen fingers as you remove the iron to prevent the solder sticking.

Yup, C1-6 begin to roll off the tone at about 16MHz 😉 C17 will isolate the input stage from the +v rail and any nasties thereon, eg 100Hz ripple or any DC variation as big currents into speaker drag it down.

Really? Those drivers must be something special, it's hard to model anything that small (per driver) with that response in winisd. Not doubting you, I know you worked with Ampeg.

Fwiw, here's the Ashdown variant. The output devices are plastic package equivalents of the originals. All now obsolete but equivalents available from Profusion PLC. Additions: C1, 2, 3, 4, 5, 6 (for hf stability?) and C17 (lf stability? Power supply noise rejection?) Ashdown ABM Schematics.pdf

2dB more

Hard Stare...or a commendation for lawyerly rule bending?

How the choice of a tant indirectly brought down a company. Probably.

Traditionally, tants were used for coupling as they could take small reverse polarity volts better than the electros of the day. Nowadays they're used where electros cant do small enough size/low enough esr/high enough capacitance all at once. Theyre a last resort at the last place i worked. They do flame quite amusingly when they lose their tempers though.

Even when they do spec the fr, I don't believe it https://www.musicstore.com/en_GB/GBP/Ampeg-SVT-810-E-Box-800W-4-Ohm-8x10-Speaker/art-BAS0000443-000

Iron Malden. The Essex tribute band twinned with Yorkshire's Highway to Hull

Is that the input coupler? I wonder why replacing a horrid tant with a nice shiny electro would cause instability. Genuine question. I use film caps for input coupling and mlcc and electros elsewhere on my clones and they're plenty stable.

They're amazingly robust, simple designs. I shorted the output to the negative rail by careless placement of a Croc clip, which arced bright white, gave off a lot of smoke and welded shut. Power off, chiseled it off and it was fine.