Tube Amp Archive

Perhaps one should pose this question?..What if you prefer the sound of a cap oriented with the outer foil facing the the higher impedance side..Should one sacrifice tone over functionality..I will keep my opinion to myself on this one..Just posing the question? The only thing that connecting the o...

Distortion changes all the old Hifi derived rules. The harmonic spectra generated by distortion doesn't change the rules. What is causing any real difference is that the caps being used have different measured values. A capacitor has internal inductance in addition to capacitance. If one takes two ...

You just opened a can of worms... Many of us have done tests on a variety of cap types and brands and find the it makes a significant difference in these amps. Even the orientation of the cap makes a difference. Some folks go so far as to use one type for the bass cap, and a different type for the ...

I am always amazed that these types of builds do not hum like crazy due to ground loops. Heck, even the input jack has a ground loop because the jack is not insulated from the chassis. Done properly, busbar grounding is not bad. It is used all of the time in the RF world. The problem with busbar gro...

I don't use Polyprops film caps as to my ear they sound harsh. A film cap is a film cap. Polypropylene caps do not sound any different than polyester caps. As long as the caps that are being compared are not microphonic, any perceived difference in tone is the result of the caps not having the same...

One has to be a complete tube amp bigot to say that the Retro Wreck is not a great sounding amp. I own several tube amps, but my main practice amp is a Trademark 30. Attenuators and master volumes are band-aids to the age-old problem of needing scalable tone and performance.

Yep. And yet the tweed Deluxe amps never had a standby.. Cathode stripping is not an issue at the voltages at which cathode-biased amps operate. Cathode stripping is a problem in tube-type RF amplifiers; however, tube-type RF amplifiers tend to operate at B+ voltages that make guitar amplifiers see...

I was using my old 1963 12th Ed. Sylvania Tecnical Manual I've had for so many years I can't remember. So I also am posting this wedsite so that you can figure out the data you are looking for. http://tdsl.duncanamps.com/show.php?des=5V4 http://tdsl.duncanamps.com/show.php?des=5Y3 You did not answe...

jjman wrote: FYI, I'm using a 265-0-265 PT with diode rectification on 2 6v6s in cathode bias @ 12 watts each. Plates are 344 volts with 21v on the cathodes and about 37ma idle ea. 250ohm cathode resistor.

What is the current rating for your power transformer?

About solder bridges you may be right, in other electronics projects (not amp projects) it's normal to use solder bridges, 'cause essentially they are like PCB paths but bigger There's nothing wrong with using solder bridges. I am a licensed amateur radio operator, and you ought to see the type of ...

I wouldn't know the difference between xx or xxx, but it sure looks like some sort of breadboard with holes in it and perfectly good material, IMHO. XX and XXX are NEMA grades for paper-based phenolic sheet. XXX is the highest grade of paper-based laminate. Paper-based phenolic sheet is also known ...

M Fowler wrote:2Amp 5V4 voltage drop is 25v
2Amp 5Y3 voltage drop is 60v
5R4 not found ?5AR4 same as GZ34
EZ81
5U4G or GB 3Amp 44v to 54v drop depending on tube conducting
5AR4/GZ34 1.9Amps

With respect to what voltage? The current values listed above exceed the continuous ratings for these tubes.

Zippy wrote:

dave g wrote:That's not PCB, it's perfboard

As the accompanying text cites, the perfboard EXAMPLE is of a TrainWreck - the OP is using circuitboard (with some pretty sloppy technique).

Dave is correct. It's either XXX or XX perfboard.

Right, got those...but I'm still trying to get the figures for the 5V4, 5R4, and EZ81, as well as the max capacitor value allowed after a 1N4007 diode... I do not have values for the 5V4 or 5R4 because I have never found a need for either of these tubes. The coefficient for the EZ81 is 1.1. As far ...

dehughes wrote:
Okay....what are your coefficients again? (Sorry...I'm mathematically challenged...)

Si diode 1.4
5AR4 1.3
5U4GB 1.2
5Y3 1.1