The Amp Garage

Formula is f = 1/6.28*R*C so decreasing capacitance or resistance is the same: both increase the roll-off freq of the filter. Consider that resistance has also an effect on the low-pass filter, so to control the bass roll-off it's easier to tweak the coupling cap only. The cathode bypass caps work a...

Hi Michael How many 6V6 are you planning 2 or 4? 372JX is huge, you can go with something smaller even with four 6V6, you can try 372FX or the newer 372HX. Voltage is ok because 372JX-HX-FX gives you 425-430 at idle. Switching 4/8/16 requires a multi-pole rotary switch, Hammonds don't have 3 separat...

Are you sure you scale the resistor based on total amp output?? I am not completely sure about the right value to scale the 100w -> 50w, I have to redo my calculations and simulations, I'll post asap. (This subject is somehow explained in O'Connor TUT3: how to make a 50w Plexi sound like a 100w) Re...

..It made me wonder how the wierd OD injput network works.. Are you referring to the 70s network? The coupling-cap/resistor/trimmer/grid-resistor network doesn't look weird to me at all. Basically it's a bandpass filter that is also used to reduce the signal, there isn't a notch, you need a combina...

..that there was something unique about the implementation and that he had never seen the technique used in guitar amps before.. I know that site but it seems to me it has been that way ever since, at least last 3-4 years, and it's not my original (lost) source. BTW I think the author is barely ref...

Thank you Scott now it's a lot clearer to me! ..the grail sounding speciman had 25uf caps on V1a and V1b. .05/.01/.005 couplers. And importantly, the skyliner stack in combination with no post OD stack.. Can't remember how and when, but I have always known this although I own a different opinion on ...

groovtubin wrote:..wondering if the DEGOOPED pix..

Hi Jim

Do you really mean DEGOOPED instead of NOTGOOPED?

I never saw a DEGOOPED Dumble, Have you? Is it so different?

Teo

Pedro

try www.tubes.it and www.banzaieffects.com, both are EU based, they carry lot of stuff.

Teo

It should be 4.7k on 4ohm tap but this is for the 100w version, so I prefer 3k-3.3k on 4ohm for my 50w.

Usually Dumbles use a 4 conductor connector to switch OD and PAB plus having a separate supply to the pedal's leds.

...due to the much lower Miller Capacitance... I just can't follow you completely here... I guess you mean that the source impedance "into" the Miller Capacitance of v2b is higher and this obviuosly lowers the rolloff freq. Miller Capacitance is given only by grid-plate capacitance of v2b (approx 3...

Not sure if there are any merits to mellowing out the high end more in the eairlyer stage vs the later, guess I should try it. (?) or is this just splitting hairs? It makes difference! Rolling off highs in the earlier stages gives more of a fuzz sound, think when you roll off with the tone pot on t...

Celestion G12H80s are very nice sounding speakers with this kind of amp but they have a somehow rolled-off high response. If you want sparkling highs you have to try some other speaker.

glasman wrote:
Part of HAD's secret sauce were those junk shop parts....

Gary

Think about those x5r mounted directly to the tube socket... terrible temp coeff and very hot environ, a genius!

Teo

Hi Bob

I see your method is very effective doing black graphics on clear background. Because I do white on black I am using the same method as Gary (more or less), but I would like to try also some real screen printing.

Have you already tried screen printing?

Teo