The Amp Garage

Hi Martin, I was actually thinking the first lytic could be deleted, but failed to mention it. Each supply leg already has a 10uF filter, and since there is no current-requirement (at the 6K6's) to speak of, the first cap isn't really needed. I haven't seen a bias supply done as a variable shunt lik...

Hi Katopan,

I too, would be very interested and appreciative to see this.

Many thanks!
JGG

Another parameter that must be considered when it comes to amp volume is speaker efficiency: 1. One dB in volume change is considered the smallest increment the human ear can discern. (Mastering engineers notwithstanding :-) ) 2. Doubling an amp's output power only increases its output by 3dB. This ...

I have asked this question of many people, and I am starting to think no one actually knows the answer. I've read Kuehnel's power amp book (and yes, I've even asked him via email) - and I am patiently awaiting Merlin's power amp book (which still appears to be a few years away). My problem is with p...

I suspect the issue stems from the 330K resistor in the head of the bias supply - this makes the impedance of the bias supply relatively high, so the more current you pull from one leg, the lower the overall voltage to both legs. You might try placing the diode before the 330K, change the 330K to 47...

I imagine the Trinity Amps Triwatt could be re-biased for EL34's easily enough. I can vouch for Trinity Amps - I bought one of their 5E3 kits a few years ago and I love it. Got a tweed cab and a Tone Tubby Alnico Hempcone speaker for it on ebay and this amp sounds absolutely marvelous. Stephen @ Tri...

I haven't heard this myself, but I have it on good authority that the 'harmonic tremolo" used in the 61-era brownface Concert is just gorgeous-sounding. But is does require 2.5 12AX7's! I am currently building an amp that uses this circuit, and I am anxious to hear it for myself. The circuit number ...

Thanks to all for your replies. The Trainwreck pages is a great resource - thanks ampdoc1 !

Hello All, I've seen schematics and worked on a few amps that have what appear to be clamping, or flyback diodes, either two or three 1N4007's in series from each of the OT primary windings to GND. It appears that the end result of the diodes is to keep the winding from going negative when the outpu...

WOW! Did this thing even pass signal when you got it? If so, how did it sound?

Hi Jana, We were talking about Fred T. of /13 Amps. I haven't been on this board for very long, but I am pretty sure that when you see 'HAD' here, it's a reference to 'Howard'. However, inside Freds's amps, near the tube chart, you will see, written in felt marker, the date of manufacture, Fred's in...

Had A Dad, that's pretty cool - thanks ampdork!

Hi Folks, Just joined the forum. I've read through a bunch of posts here in the last few days. The first time I saw someone use "HAD", i thought it looked familiar. After thinking about it, it occurred to me that this is a reference to Dumble. However, Divided By 13 amps bear the same acronym. Does ...