Author: James Low

The M1 iMac Should Have Been USB-C Powered

The new M1 iMac is sure to be a hit, but given its lower power processor, it would have been great to make it USB-C powered, so a power supply could be shared between the iMac, MacBook, and iPad, now all running the M1 processor. USB-C supports power along with data, so the ethernet on the power supply (which is a great idea.) could still be included and made available to the MacBook and iPad. It would have also allowed USB-C wall power sockets to start becoming a standard, which could also start including the ethernet connection, wired internally in the wall. At the very least it should have done a MagSafe connector which was the same as the MacBook, which is rumored (leaked!) to be on the M1X 14″ and 16″ models, scheduled for release mid-2021, but it looks like the connector for the iMac is far too big to work on a laptop.

M1 Mac Mini Internal Storage

Was looking at the M1 Mac Mini and wondering if you could fit some extra internal storage inside all that empty space. I’d love to see someone do this:

  • Add a USB to M.2 SSD in the extra space.
  • Take slim right angle cable out through the fan vent and plug it in a USB-C port out the back.
  • For the extra brave, maybe they could desolder one of the USB sockets, and attach the cable directly to the motherboard.

Update:
I realized this was probably more trouble than it’s worth when you could just stick a tiny 512GB USB, or maybe in in an M1X Mac Mini Pro use a 1TB SD card.

Buffer With Relay Bypass

Just a quick schematic of a buffer with relay bypass. The relay bypass means that if you lose power, the relay switches back to bypass and you still get a signal like the TC Electronics Bonified Buffer.

  • Based on JHS Little Black Buffer
  • The value of R will depend on what voltage/spec relay you have
  • Most opamps are in 2 in 1 chips. The unused side is wired to prevent noise/oscillations

Train Wreck Type-2 Lar-Mar on a Victory V40

I’ve been looking at doing a post phase inverter master volume mod to my ’68 Fender Vibrolux. I was wondering about using what was on the Victory V40, since it is a American-style tube amp. It turns out they seem to use a Type-2 Lar-Mar but with a larger value pot, and smaller value safety resistors.

I think the advantage of this setup is that with the resistors in parallel, the lower resistance makes more difference when calculating the total resistance. The better tolerance of the fixed resistors keeps the total grid leak resistors more consistent between the two power tubes, as pot tolerances can be ±10% of the stated value.

Here’s a comparison:
1) 10% tolerance 250K pot in parallel with 1M resistor:
Min = 225K x 1.0M / 225K x 1.0M = 184K
Max = 275K x 1.0M / 275K x 1.0M = 216K

2) 10% tolerence 1M pot in parallel with 250K resistor:
Min = 0.9M x 250K / 0.9M + 250K = 196K
Max = 1.1M x 250K / 1.1M + 250K = 204K

As you can see, even though the pot tolerance is the same, the end result is a much smaller deviation between the 2 grid resistors with a 1M pot vs a 250K pot.

PRS Piezo Options

I’ve been looking at modding a PRS singlecut with a piezo pickup and a middle single coil. Models I’ve been looking at are:
– S2 Starla
– SE Zach Myers
– SE Tremonti
– SE Singlecut Trem

These all have a different bridge but are all a bit non-standard, so I’m documenting a little of my research as it took a little time and emailing to come across.

1) TonePros AVT2P
TonePros make a wraparound bridge that use standard tune-o-matic saddles. You can then get some piezo saddles from RMC Pickups

2) PRS Trem with RMC saddles
RMC also make some Piezo saddles to retrofit PRS tremolo bridges

3) Replace PRS Tremolo
You might be able replace the PRS tremolo with a 6 screw piezo, but the screw spacings might be slightly different, so might be hard to make it work:
– PRS seem to be 52.4mm (2-1/16″)
– LR Baggs (Vintage 6 screw) 53.98mm (2-1/8″)
– Fishman 56.38mm

4) Graphtech Wraparound
Graphtech make a complete replacement, but it’s pretty expensive and has 6 separate piezo leads that need to be fed to the cavity and joined using their circuit board.

5) Replace Tune-o-matic
If you have tune-o-matic bridge like the Starla or 245, there’s a pretty affordable bridge available on eBay, along with more expensive solutions from Fishman and LR Baggs.

6) Modify a PRS Trem
Because the tremolo block can be unscrewed from the top plate, you may be able to wedge an element between them like the video below. This might be worth experimenting with since it’s completely reversible and the elements themselves are only about $5.

7) ABM Piezo Wrap Around
AMB in germany used to make a wrap around piezo bridge, but when I contacted them said they no longer did due to low demand.

8) Q-Tuner Magnetic pickup
You may be able to add an additional Q-Tuner magnetic pickup, which has a large dynamic range and more capable of capturing an acoustic sound, especially when combined with something like the Fishman Aura Imaging DI.

Flip-Flop Loop Switcher / Dual Pedal Switcher

I have a couple of DIY overdrive pedals that I never have on at the same time. So I wanted to house them as a dual overdrive and then add Flip-Flop switching so that to go from one pedal to the other, instead of having to turn one off and the other on, you just turn on the one you want, and it automatically turns the other off. Could be used for a true bypass looper as well to switch pedals in the same manner externally.

So far I’ve done this with counter ICs. I planned to try and do it with a single dual J-K Flip-Flop with asynchronous reset, but I couldn’t get the clock debounce to work with that. Eventually, I came up with a clock circuit that works with a dual counter chip:

Schematic using dual counter chip:

Schematic using 2 counters. This uses a different debounce circuit which I’ve found to work with that chip:

I also chanced upon a debounce circuit that worked, when all the other types I found on the internet didn’t work that well with this particular IC chip. I’ve drawn out just that portion incase it’s useful to anybody else struggling with a chip clock timings. Even though both the 9V and GND should be AC ground, I found it would only work if I decoupled to both the positive and negative of the power supply:

Wampler Velvet Fuzz 4PDT Plexi Switch

I’ve been thinking about building or modding a Wampler Velvet Fuzz with a switch to access the plexi drive part of the circuit separately. You can do this with two separate toggle switches, or an additional footswitch, but I was wondering about trying to put it on a single 4PDT.

There are two different versions, one for if you use the vero layout that is around on the internet that skips out the optoswitches that are in the original pedal, and one that would work to modify a Wampler made Velvet Fuzz.

Links:

Thoughts on the Dumble tone – an honest review of the Two-Rock Jet and comparison with the Victory V40

Two Rock Jet 2x10 stack cab

Victory V40 Viscount Combo

I always wanted a Dumble style amp, having discovered Robben Ford and Larry Carlton early in to learning guitar. I tried building one, bought pedals, tried modelling software. I was also looking for a two channel amp with Fender cleans and bluesey overdrive. I recently had the change to pick up a Two-Rock Jet 22 for a really good price, and so I pulled the trigger. I took a while to get the speakers for the cab, so I had it sitting around for a while before I got to play it. When I finally did it was probably one of the most disappointing experiences in trying gear. It just wasn’t the tone I hoped to hear.

I think the primary reason for that is that the Dumble Overdrive Special tone is a very mid pushed sound, the so-called Dumble “bloom”. The Two-Rock Jet had this in spades, on both the clean and the dirty channel. I’ve primarily been a Fender amp user, and this just wasn’t the type of sound I like, which is more mid scooped. This sound really needs to be run at higher volumes to sound good, so that the mid compress into a harmonically rich tone and aren’t so pronounced. It definitely didn’t sound that good at lower volumes.

I tried to give it more of a scooped clean, with the bright switch on mids turned right down. This was closer to the Fender tone, but still didn’t sound great, and it at too negative side effects. Firstly the overdrive sound was basically unusable, sounding really thin and brittle with all the mids taken out. Secondly, pedals, which already didn’t seem to work that well with this amp, started to sound all harsh and fizzy too.

The amp also had some manufacturing issues. Firstly the Reverb tank was put in backwards, which caused it to hum really badly. After contacting Two-Rock I switched this around and it was much better. Even after that though, if you turned the Reverb up high the hum was quite noticeable, which Two-Rock said was down to the small size of the Two-Rock Jet head. However, it was probably the best sounding spring reverb I’ve ever tried. Really lush, yet not as “splashy” as the spring Reverb in Fender amps. The second issue was that the chassis still at the power supply marked as 100/110/230/240V, and had not been blanked out to only list the voltage it actually worked at. It was built during the Premier Builders Guild days, so I think standards have improved since that time.

Maybe in hindsight, I might have been happier with a Two-Rock Studio Pro, although others have said this isn’t really a Fender clean either having more mids and less high end. I think a lot of people got interested in Two-Rock after John Mayer started using them. This started the myth that the Dumble/Two-Rock clean is like his tone, which many people spout of on forums like The Gear Page. However, his signature amp (now the Two-Rock Crystal) is much more like a Fender, and probably more like the Dumble Steel String Singer, which is very different animal to the Dumble Overdrive Special, and what at least in the past was considered the Dumble tone.

On to the Victory V40

I eventually managed to trade it all in for a Victory V40 Viscount combo which ticked all the boxes for me. Fender clean, takes pedals well, low power mode for great sound at lower home volumes. Here’s a rundown of what else I considered and why I eventually chose the Victory:

Two-Rock Studio Pro
As I said before, this still doesn’t really have a Fender style clean, and needs to be louder to sound good.

Two-Rock Crystal
Maybe more along the style I’m looking for, but it’s way more expensive than either the Jet or Studio Pro, and has a Celestion Gold speaker which might mean it’s less suited to pedals.

Mesa/Boogie Recto-verb 25
Some people say the clean can be Fendery on this, others say thtat it’s still stiff like Boogies are described to be. It was interesting because of the seperate eq and reverb for the two channels, and being able to to low and high gain on the drive channel. I eventually decided it was too expensive, too heavy and probably too loud.

Fender SuperSonic 22
While still looking at two channel amps, I did look at this offering from Fender. Maybe it’s again something I should have tried, but there weren’t that many around, it was still pretty expensive, and I wasn’t that sure about the drive channel

Fender Deluxe ’65/’68 Reissues
I owned a ’65 Deluxe before but didn’t know about the bright cap mod, so never found it worked great with overdrives. The ’68 seemed to address some of these problems and having tremolo sounded nice, but I always felt that vintage Fender amps with 2 channels were overly complicated and expensive to re-valve, when these days we tend to just want a single clean channel. Again for a mass produce amps, this seemed pretty expensive, maybe to loud, and I’ve recently come to see that Deluxes don’t really have the big deep bass associated with other blackface amps like the Super Reverb or even the Princeton.

Fender Princeton ’65 Reissue
Furthering the search I starting thing about a Princeton, because it does seem to have one of the deepest and sparkliest Fender cleans. But here there started to be the opposite problem, not enough clean headroom when playing live.

Fender Princeton II
Somehow in all of this I then started stumbling across discontinued amps. The Rivera era Princeton II seems to be the perfect amp between a Princeton and a Deluxe Reverb, however, there don’t seem to be many 240V models around, so trying or buying one seem unlikely.

Fender Super 60
A friend of mine had one of these, and the clean sounded amazing, but at 60W it seems a little impracticle for home use, and he said while the clean is amazing, it really didn’t take pedals. well.

Fender Blues Jr.
I owned one of these before, and when I was initially disappointed with the Two-Rock, I wish I hadn’t sold this amp. But I have always found Blues Jr. to sound boxy and small, and mid pushed as well, even after doing the Billm mods and putting an ET-65 speaker in it.

Fender Hot Rod Deluxe
I’ve always felt ok about the Hot Rod Deluxe clean channel, but these things are loud, and just like the Princeton and Deluxe, there seemed to be the need for something between the Hot Rod Deluxe and Blues Jr.

Fender Deluxe 112 Plus
Starting to get desperate I started looking at cheap solid state amps, hearing that maybe they aren’t that bad, and maybe it would be good not to have so much money tied up in an amp. But these were that available in Australia, although I could have got one cheap before I left the UK, doh!

BOSS Katana 50/100
Wondering if I should settle on something affordable I started to look at these too. But I did something similar after selling the ’65 Deluxe, buying a Superchamp XD, and wasn’t really happy in the long run.

Victory V45 The Count Combo
Finally, before I decided on the V40 I looked at the V45 (V30 in head form), which still had two channels. But I knew I wanted reverb, and the clean channel isn’t supposed to be as vintage or Fendery as the V40, which kind of was the whole point of looking for something in the first place.

So finally I ended up with a Victory V40. I’ve always used combos, the Jet was my first head, and I think I like the all in one thing better. The clean is great, deep and sparkly, but still takes pedals well. It has vintage tone, but modern conveniences like low power mode, and a few switchable eq settings that give you something with more mids and a flatter eq response if that suits your needs at the time. I think the only thing I wish is that the reverb was either a digital or real spring reverb. The digital reverb is a plate reverb, which doesn’t splash quite as smoothly with the transients when you dig in, which means I feel like I have to keep the setting on the low side. I’m not entirely sure, but I think it also has a pre-delay, which makes it feel even drier, when players like me use the reverb to cover their sloppy chops! But having said all that it is still the best amp I’ve ever owned and the closest to the sound I would love to get. I love playing it more than any amp before, which makes me want to play more, and even my wife things it sounds better than either the Blues Jr. or Two Rock Jet!

Two Rock Footswitch Schematic

I recently was fortunate enough to acquire a Two Rock Jet 22. I wanted a footswitch that was smaller to fit on my pedalboard. Here’s the schematic I worked out and a shot of it working with the amp and how much smaller than the actual switch it is. On the Jet it switches boost and channel but may work with other Two Rocks that have a two button switch to switch boost and reverb.