Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: jimmybjj on April 09, 2010, 10:04:26 am
-
I'm still new to all this and purchasing tesing equipment. my wife has approved the funds for the purchase so I've go to jump on it while she is still saying yes :) my requirments are; it has to be new. and I has to be basic. I know there is alot of advocates of purchasing used but I am not one. I have had many occasions where things didn't work purchasing used electronics and want to avoid that. For he second requirment, I want basic. I don't want alot of funtions that I will never using outside of working on tubes amps. the extra funtions usally cost more and they make the instrument more difficult to use. thanks for any advise and information.
-
The cheapest BK precision you can get will be more than adequate for tube amps, and have everything you will need. $600 though. Dual trace/Dual channel is a very handy feature. A nice big screen is nice too.
I am sure you can get cheaper, but I am not familiar with other brands. You may also want to consider a PC based scope, if you already have a PC in your shop.
I presume you already have a signal generator?
-
> I'm still new to all this
Flip a coin. A 'scope is not an essential tool for audio amps.
I know I learned a LOT by having a real junky 'scope when I was starting.
OTOH, some very fine fixers, builders, and designers never use a 'scope.
There are low-price CRT 'scopes around $299. AFAIK, these are imitations of the good Leader 'scope I got in the 1970s for something like $600 (beer was still 50 cents), and more than good enough for our uses. Really "too good", but they don't make anything less anymore.
I kinda like my LCD Velleman, was $280 but the newer model is less. I do HATE having to thumb-pad settings that were intuitive on a bunch of knobs, but the knob-board on a "real" 'scope is bigger than the whole Velleman. Another point: any CRT 'scope is BIG. Takes half my bench, or really forces a larger bench (or clever shelving which was not my thing). Domestic partners are sensitive to how much space your "stuff" takes up. The LCD 'scope is roughly the size of an iPad (am I the first to make that comparison?); small on the bench (but it falls down), EZ to stick in a drawer.
-
LCD Velleman... cool...
-
> I'm still new to all this
Flip a coin. A 'scope is not an essential tool for audio amps.
The voltmeter is your friend. Scopes are great, but you can tell a lot about what is happening during initial troubleshooting by just looking for voltages that aren't in spec. I actually still use my RCA VTVM occasionally when I really want to go "old school". :wink:
-
As others have stated, any ol scope is good enough for audio but dual trace is a huge plus. It's nice to be able to look at input and output simultaneously so you can actually compare phasing and gain etc. I wish my scope had a larger screen but truth be told, I don't really use it all that much as compared to my trio of DMM's. My Hickok VTVM is older than I am by a lot.
-
I know there is alot of advocates of purchasing used but I am not one.
It would be nice if you had someone to pre-check a used scope for you, and verify proper operation. I paid about $200 for a Tektronix 475 DM44 scope, which sold new in 1982 for $4500-5000. It has much higher bandwidth than I'll probably ever use, but functions flawlessly and is better (and probably easier for me to use) than perhaps anything else I could have found at that price.
But I'm willing to buy used if I can either fix any potential flaw, or when I know upfront that there are no issues. In my case, I got lucky with a scope with no issues.
-
thanks for all of the replies. I think I am going with a bk 2120b, any opinions?
-
That'll certainly work just fine for tube amp purposes. Make sure to get switchable 10x probes so you can measure large signals.
-
well I ordered the 2120b they called me back and said it was out of stock. they said they would give me the instek gos-635g for the same price, is this one any good? thanks
-
No clue about the brand, but it has enough features to get the job done.
-
One feature I have on my Tek 2246 which I find very useful is a voltmeter and a frequency measurement - right on the scope. I use it all the time. I wonder if you can get a new scope with these features. PC based scope all have this type of feature.
I know you are not a fan of used scopes. However, I purchased both of my used Tek 2246 scopes for less than you will purchase one of your B&K/Instek scopes. If you reconsider used, peruse ebay for Tek scopes, and post the candidates here. We will be more than happy to see if they are good enough.
Here is a pic of a oscillation riding a 60Hz hum.