The Amp Garage

I went looking for one of those at the local store the other day. None to be found, but the clerk ordered one up as a "direct to customer" sale, which means it will be shipped to my house, no charge. Isn't it sort of "traditional" to have a Radio Shack relay supply tranny in your D-style amp? Part o...

As I understand it, the precision PSU is part of the later dumbles. I have a few questions about this: - I suppose two 47uF in series reacts faster than one 22uF. Is this right? - Is there a difference in performance between two 47uF in series, and two 10uF in parallel, as long as voltage rating is...

About 18 hours too late for me :^(

David, You are most welcome, and thanks for the applause. I don't have Tube Cad, but please let me know if it seems to disagree anywhere. I used available data sheets that were of good quality, since it is tedious to digitize them. The Sylvania 12AX7 sheets are a work of art. If you or anyone else w...

Hi, I've looked at getting something like this, but I haven't done any in-depth research... How does this unit compare to Tascam's DR-1? Is it maybe on sale because there is a new model coming out? Re Sweetwater, dunno what your experience has been, but I have had good service from them. Their new f...

Thanks, guys. Feedback and questions will inspire improvements! Tom, the beauty of the numbers is that you can see where your operating points are, how they move, and what will happen to the frequency response as you change the values of the R's and C's. Phil, yea, I don't think you or your clients ...

Here's something I've been working on for a while that others may find useful. This gathers up knowledge I've gained from a variety of sources including this forum and, notably, help and encouragement from the Valve Wizard. Constructive feedback of any kind is welcomed, as I'm sure it is not perfect...

Ron, Really great stuff here! I'll definitely have to take some time to read through this material. My $0.02: Skimming through I noticed that on page 46 of the build guide you have: 4. Using a DMM, Place the black negative lead onto a good chassis ground. With the red positive lead, check and adjust...

Great thread here; lots of useful stuff! ...To me it is one of two things, the OT has the wrong impedance for the voltages, or the power supply lacks the headroom needed. Both of which as pretty easily to check and if I have another one here I will check both. Can you elaborate a bit on this? Re the...

Martin, great job!! If you're doing a dead on 124 clone this looks good. However, I'd probably consider going a little more generic on the back panel, lose the square switches, adding an impedence switch. losing the auxillary outlet and doing a cutout for a din jack instead of the XLR. Thanks! I do...

Not being happy with any of the currently available D-type chassis, I decided to try to make a drawing from the #124 info. I think the attached file is pretty close now after a couple of days of nudging things around to agree with pictures and known part dimensions. Any comments?

MPM

My God, all the jack and switch mounting nuts are oriented the same!! :shock: I think someone previously observed that the nuts on the front panel toggle switches have been positioned "in phase." Another fine example of this type of obsessive behavior can be seen on a certain record-setting airplan...

Not to 'jack this thread (and you know that means I'm going to try...) What other examples of Dumble tones are out there? Steely Dan is one of my favorites, as is Joni Mitchell's Miles of Aisles (a desert island disc for sure) and I'm aware of the David Lindley and Jackson Browne associations with D...

It seems like balancing the idle currents to zero out the net current through the OT primary (the static part) would always be a good thing, and then balancing the "effective" Gm on each side with the PI trimmer (the dynamic part) would be a way to get a symmetrical output (or un-symmetrical in a co...

Not to hijack the thread, but BB is like George Burns. Those stogies should have killed Burns in his 70's, but nope. BB's been fat for decades and as big as Shamu for about a decade. Obviously, he's relatively healthy as far as his cardiovascular system goes. At 83, he's way past the biblical three...