The All Purpose Advice Thread - Part 2

Resistance is easy to measure because it is a static value. Yes, you just switch to the ohm symbol and touch the two ends of the probe next to the object that you want to measure. Note that if the object is part of a circuit, then you wind up measuring the resistance of the entire circuit which may bugger up you rmeasurement.

Impedance is not easy to measure because it changes with frequency. Also how to get there depends on what you're measuring. If you're only just starting to figure out a DMM, we'd best leave this lesson for a later day.

 

A bit of a weird one, but: I'm looking to compile a list of amps--could be pre and power or integrated--featuring switchable voltage. Anything come to mind?

 

My Bel Canto amp was multivoltage, not sure about their integrateds or pres.

 

My Meier Audio Jazz FF has switchable voltage. Not sure if you’re looking for headphone amps, though?

 

I was looking at moving to Europe for a bit a few years ago ... I seem to remember Benchmark, Rotel, and Emotiva amps were either universal or switchable (maybe with a jumper?)

In terms of direct experience, the NAD M10 v1 I owned was universal voltage, and same with a Parasound pre I had -- forgive me I don't remember the model. My NuForce STA200 (Goldmund design, based on the JOB 225) is switchable.

 

I got an MCTH the other day with an incompatible power supply. MassDrip cannot help, anyone know what I need in terms of barrel size and any other funkyness in relation to specs? What I read in the MCTH thread makes me think that it is a split rail supply which is all Greek to me.

 

Incompatible, how? It doesn't power it up?

The required PS for the MCTH is 28V and at least 1.5A. @atomicbob found the stock supply has a some sort of soft-start mechanism that limits the inrush current on startup, so although it's fine at its specified 1.25A. Others, though, might not be, especially if you're doing some tube rolling (which, with this amp, should be limited to 6DJ8/6922 types; others have used other types with success but the designer has recommended against it).

The barrel connector is 5.5x2.1mm. 2.5 will fit but might give an intermittent connection.

The split rail design means that the power supply -ve must float, ie must not be connected directly to ground. See here for details. The barrel connector takes care of that.

For something cheap just to get you going, this would work. 28V, 2A, with a barrel connector that has the internal spring grips so should be fine into a 2.1 or 2.5 jack. But as many of us have found, a better PS does have benefits with this amp. Have a look through the thread to see what others are using, and maybe go for one of those cheap Ebay linear units. 28V, and at least 1.5A (so more than 40W).

 

It is just the all wrong PS, 12v. Thanks for the link, I have been reading through that thread, will make it all the way through, but got the split rail comment and thought it better to ask!!!!

 

Seriously, some arsehole sold you a MCTH with a 12V power supply?? Strong negative feedback required!!

 

And a pro-ject carbon dc and tube box s2 without PS... Had a bit of hassle with that. Oh and the 2M red was bent. But he is a good kid. I will get it back someway!

 

If the sale was via a public forum, please do provide feedback. I, and I'm sure a lot of others, would rather not deal with a "good kid" like that.

 

No, he is a college kid who needed money badly. I'm a bit miffed about the PS's but I will get money back from him! No need to worry about that. It was outside of any forum.

 

@SofaSamuraiX , for the MCTH if you don't mind a little bit of DIY - that is, wiring a mains socket (ideally fused), a barrel plug, and putting it in a case - you could try one of these at what seems a pretty good price:

https://www.antekinc.com/50w-linear-power-supply/

Select the 28Vdc 1.8A version.

 

I didn't mind! Thanks for that!

 

I've had problems with cables and switch ports that show similar problems. I'd try changing switch ports and then also confirming the wiring is up to spec. I've had to re-terminate Ethernet jacks that electricians installed because they didn't keep the leads (?) short enough which caused signal problems.