Killing the hash PO

[Structo]

They also have this bench top model that is 10Mhz for only $200.

http://mcmelectronics.com/product/TENMA ... 0-/72-6800

[Structo]

Is it advisable to use a dummy load when looking at the wave forms on a scope?

What would I use for a 50 watt amp? Just a 50 watt 8 ohm resistor?

[Bob-I]

Is it advisable to use a dummy load when looking at the wave forms on a scope?

What would I use for a 50 watt amp? Just a 50 watt 8 ohm resistor?

I'd double that to a 100 watt 8 ohm resistor. If you want to be very safe use an attenuator before the dummy load.

[Structo]

Should this resistor be non-inductive and is it necessary to mount these onto a heat sink or enclosure for heat dissipation?

[M Fowler]

Mount on a piece of wood and leave open. Use the same kind of resistors that are used in the airbrake at 4 ohm, 8 ohm and 16 ohm 100-150watt rating. You can use three jacks labelled for each ohm.

Mark

[Structo]

How about something like this?
It's actually cheaper than the gold anodised wirewound resistors at Mouser.

http://www.parts-express.com/pe/showdet ... nd=4622316


[img:400:188]http://www.parts-express.com/images/ite ... -020_L.jpg[/img]

[butwhatif]

Is it advisable to use a dummy load when looking at the wave forms on a scope?

What would I use for a 50 watt amp? Just a 50 watt 8 ohm resistor?

Yes it's advisable--unless you want to exercise your ears with test signals--
Also advisable to get a large wattage load resistor--somewhere along the line u may want to work on a more powerful amp-- most solid state amps are way more output, and will heat up a load rather quickly. Also nice to have an
8 ohm, 4 ohm, and 16 ohm load--- best to have a large air cooled one, rather than a heat sinked one---

[heisthl]

If you dont want to mess with heatsinks just save your used motor oil in a 5 gallon bucket - solder the resistor to a speaker cord and drop it in the bucket. You can run your amp all night and not get the oil very hot.

[butwhatif]

Know any electricians? Big wound rotor motors take resistor banks for starting--
these can be had cheap--surplus, and can usually be adjusted or cut for value---that's what I have---

[Tonegeek]

If you dont want to mess with heatsinks just save your used motor oil in a 5 gallon bucket - solder the resistor to a speaker cord and drop it in the bucket. You can run your amp all night and not get the oil very hot.

I would be a little worried about using used motor oil because there could be unburned gas mixed in with it - and if you had a spark...
Also, I imagine the fumes are not too healthy either. If you could seal the whole bucket with no airspaces, you might be ok on both accounts. I AM NO EXPERT just good at visualizing bad scenarios, however unlikely

[heisthl]

If your worried about explosions throw a match in it when its still in your driveway. The match will go out, as to the fumes - it smells like the race track

[Structo]

A couple of weeks or so ago I did some research on dual opamps.
I am using the Ironsounds FX loop in my D'Lite and it uses the TL072 dual opamp.
I contacted Ironsounds and asked if anybody has ever complained about their loop creating distortion.
They wrote back and said, nope, you are the first.
Just my luck.

I know, a Dumbleator would work much better but for right now it is what it is.

I seemed to notice more fizz/hash when the loop is in circuit so I am going to mess with that.

In researching the dual opamps there are much higher fidelity chips than the TL072 IC.
The TL072 has gotten a little long in the tooth as far as modern opamps go.
It seems the faster the slew rate and lower distortion of the newer chips should help me out if in fact it is the FX Loop that is causing me trouble.
So I ordered three or four different dual opamps from Mouser.
I then went on vacation and was gone all last week.

The 5332 gets high marks from the Hi Fi crowd and a couple others as well.
I can't remember what other opamps I ordered but I have a box sitting here from Mouser so I will try and Plug and Play later today to try the different opamps out.

[Tonegeek]

If your worried about explosions throw a match in it when its still in your driveway. The match will go out, as to the fumes - it smells like the race track

Well, that would go over real big here in N.C., the home of Lowe's Motor Speedway

[bluesfendermanblues]

A couple of weeks or so ago I did some research on dual opamps.
I am using the Ironsounds FX loop in my D'Lite and it uses the TL072 dual opamp.
I contacted Ironsounds and asked if anybody has ever complained about their loop creating distortion.
They wrote back and said, nope, you are the first.
Just my luck.

I know, a Dumbleator would work much better but for right now it is what it is.

I seemed to notice more fizz/hash when the loop is in circuit so I am going to mess with that.

In researching the dual opamps there are much higher fidelity chips than the TL072 IC.
The TL072 has gotten a little long in the tooth as far as modern opamps go.
It seems the faster the slew rate and lower distortion of the newer chips should help me out if in fact it is the FX Loop that is causing me trouble.
So I ordered three or four different dual opamps from Mouser.
I then went on vacation and was gone all last week.

The 5332 gets high marks from the Hi Fi crowd and a couple others as well.
I can't remember what other opamps I ordered but I have a box sitting here from Mouser so I will try and Plug and Play later today to try the different opamps out.

I think you a got a little OT here

I wouldn't expect a revolutionary sound improvement by changing ICs in a buffered loop. It should be transparent. Period.
However, in a tubescreemer its another story, where the right JRC4558 is important. Conslusion: Use the loop as is and build a dumblulator when time and money is avaible and plentifull

[wjdunham]

I would agree that changing the opamp would not be the first place I'd look if my loop was excessively noisy or distorting - I have the Ironsound loop in my DLite with the stock opamp. The Ironsound loop is fine, the outboard effects I'm using are far noisier than the loop. If you're getting distortion from then maybe there's an assembly problem there or something, did you buy it pre-assembled or the kit and assemble it yourself? It was a little tricky figuring out the best place to ground the power supply and the signal grounds on that thing, maybe that's causing your noise?

Bill