The Amp Garage

Don, you are much more adventurous than I. My plan is to do an ODS with a few minor layout changes and a modernized back panel. This really needs to go into a CAD program so it can be modified as needed and handed to a fab shop when the time comes. I'll likely get to that in the next few weeks. mlp-...

Well, I drew this in Powerpoint so I don't think that will be of much additional help to you. I'm looking at getting some quotes from local fabricators once I get everything dialed in for the compopnents and mounting hardware I'm using. I'll have to put it into a real CAD program for that, but it mi...

I made a little update on this. A forum member suggested that it might be nice to have some extra slots and buttons for additional tube types available, so this version has that feature. No bugs reported so far in the original version. Cheers, MPM Edit: attachment removed. See latest version posted ...

all of the coax i have, can be attracted by a magnet, rg59, 162, and i can't say that about any of the audio cables i have. I can't offer an explanation why, but i have had issues with use of it in amps. The explanation is simply that there is some ferrous material in it. That is definitely not the...

All coaxial cables, including those used for audio, will have a characteristic impedance (i.e. the 50-Ohm or 75-Ohm value you see listed). For cables that are to be used at audio frequencies, though, it is of no consequence and so it is not specified. Magnetic? My snake oil sense is tingling... The ...

...Even given the vagaries of this simple analysis, I don't think there is anything to worry about using 30pf/ft cable, is there? MPM Hard to tell because of the preceding tone stack, I guess your analysis assumes the output impedance of the TS is 0, which is not actually the case. Also, you analys...

Exhuming an old thread here... A quick analysis (-3 dB corner points) of the six runs typically seen in an ODS-type amp shows that the one most susceptible to signal loss in the AF range is the volume wiper to V1b, where the signal path sees the top of the pot to the wiper as a series resistance fol...

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...