The Amp Garage

Here is a paraphase I use, it is old school but I like it. The NFB can be switched in or out. With the INV cathode bypassed it has a nice aggressive sound. With the INV cathode unbypassed and no NFB it sounds warm. With NFB switched it cleans the amp up. The 100n cap on the NFB is optional as presen...

I am building a Supro inspired amp. I have an original 1600 Supreme, a rats nest chock full of ceramic disks. I have never used ceramics in a build other than small ones in tone stacks, bright caps and so on. I remember seeing a scope trace showing quite a bit of hysteresis with ceramics. Any recome...

I really like the idea, the minimal loss but useful bass and treble are nice. I have been scheming on something similar thing based on a Supro, with its paraphase, 6973s and quirks. Looking at the schem, I am wondering if the volume pot in the circuit feeding the OD will be too interactive. A change...

The small cap across the PI plates in either a LTP or Cathodyne is there to stabilize the negative feedback loop to not oscillate, or “slug the pole”. Output transformers have a -3db point or pole (high frequency knee) at around 60 kHz, and can have a near 2nd order response and a phase shift of wel...

In the 90s, I modded a BF Showman with dedicated clean and OD as you suggest, pre-TW and Dumble days. Short answer is it resembles a BM with stack lift PAB. OTOH, with this OD you’re not concerned with how it sounds clean or how it sounds with a pre-OD stack, so your tweaking may go new places. My n...

I looked at Marshall Silver Jubilee schematic because Joe Bonamassa likes them. Not a D amp at all, diode clipping OD. But, the post pre-amp tone stack is sort of a mutant skyliner. Here's my take on it. The mid leg is a100k slope with a .01uf-100k to ground, skyline-esque. But there's a 470pf from ...

I hacked in a change yesterday and played it at rehearsal last night. I saw this thread and it fits right in. I have flopped between HRM and non-HRM several times; it always seems the choice is ratty or muddy, clean is thin when OD is just right, especially with more than 1 guitar/pickup. My hack is...

Steve's Tube Pages have scope traces of different capacitor types. All of them have some sort of curve, and definitely hysteresis in some. Ceramics have a lot going on, almost like an active device, and there is a big difference between high and low voltage. You ears are still the guide, but it is a...

For testing, I placed the switch on a push pull pot for the bass, all I could find was a A1M, the taper is a little off, but no great difference. It could have been the volume as well, so A1M would be right. The test mule board wasn't originally done as a D-style and has become a Frankenstein, so ac...

At the risk of creating another penile measurement contest, does anybody think HAD could clone one or more of his own highly regarded builds, if he wanted to? I am really interested in the opinions of builders with several builds under their belt and new production parts. From my more limited experi...

The drawing is of my main stack between V1a and V1B, and it does have the 47k as shown. I haven't experimented with the tap point, my initial go was more of a mimic of the BM stack. I thought about reversing the 100k and 47k and using a 22n or 47n bass cap, more like a Wreck. I felt that might not b...

These are done with Marshall, impedance adjusted for no CF. There are 3 shots with treble at 0, one with treble at 10, mid at 0. With treble 0, mid at 10, cut goes from 5 db at 80 hz (~E2) to about 11 db at 200-300 hz (~A3) on, with a hump in the bass. The dimed mid has relegated the treble to boost...

What I play the most is a so-what 90s LP with Fralin unbuckers. Coil tap for SC is wired and is useful, but played mostly as HB. Also use a reissue 57 Strat and an early 70s Tele with Lollar special PUs. That covers a lot of ground. The Strat has been by far the hardest to get a good OD sound with. ...

While I like the Skyliner Tone Stack, it is just too thick for my taste on some things. I tried the 10n/22n/47n switch on the mid-cap, but it didn’t quite do what I wanted. Here is what I ended up with, the ‘trick’ being the split slope resistor. I’ve been playing about a month with it, happy so far...

It should be feasible to use a BMP in place of the HRM tone stack. IMHO, the Marshall stack in a D style provides a) a treble bleed, b) limits component tweaking often needed with non-HRM and c) has a sound we all know. HRM adjustment is far from obvious though. The Duncan tone stack calculator show...