[sam]

hi guys
would a 7b7 be the same as 7r7 ? looks same if not any thing close to it?
thanks sam

[morzh]

Sam

Why don't you simply punch both tubes in the search and see the datasheets?

And no, they are not the same, one is a double diode-pentode and another is a pentode.

[Eric Adams]

Try this: http://www.google.com/url?sa=t&rct=j&q=&...7100,d.cGE

I keep it on my desktop.

[klondike98]

Thanks for the reference Eric, had not seen that before.

[sam]

thanks eric

[Eric Adams]

Glad I could help.

[TA Forbes]

Something I recommend every collector have at their disposal is a Tube Substitution Guide. They are plentiful and cheap. You would be suprised at how many valid substitutions there are.

Also good to have are Receiving Tube Manuals. Personally, I use an RC-17 (1954) and an RC-30 (1960s).

The RC 17 covers the earlier tube well while the RC-30 covers all the newer stuff.

[exray]

You won't find a tube substitution manual in my shack. Quigs either!

Brand new 7R7 is 3 bucks at Bob Dobush www.findatube.com Why introduce unknown parameters?

Its not WWII anymore, guys, and we have access to more parts and tubes than the guys in the 40s-50s ever did. No justification to do hack repairs.

[Eric Adams]

Ease up exray , I don't have every tube that I need at hand and If I'm in the middle of a restoration and in need of a tube, I'll go with a substitute. At least until I can order the correct one. Also, I don't like to wait 2 to 3 weeks for a tube, so Bob is not on the top of my list. Try AES.

[sam]

hey guys
I`m with eric on this one I contacted bob for knob and tube after several em`s finally got price sent payment then he asked me for a pic of knob, hmm if I had knob I wouldn`t be buy one ? hopefully I will get right one
but some times to finish or just test a sub is great or if one falls off table and breaks (things happen ok)
sam8)

[exray]

Sorry, I didn't mean to sound so harsh. But fact is that tube subs can often lead you down the path of more head-scratching problems.

[Ron Ramirez]

Bob sells knobs??? I thought his main stock in trade was tubes...

If you want to give AES more money for the same tubes, good luck to you. I'd rather save my hard earned $$ and buy from Bob. As I get older, I am (slowly) learning that patience really is a virtue.

[Eric Adams]

Not only is Bob slow, last year I was looking to get a signal generator repaired. It was transistorized so I was lost. Bob told me to send it to him and he would take a look at it. Months went by and after countless emails and many excuses from Bob (it's ready to go, I just have to test it one more time. I've been busy. I'll get to it soon, etc). I told him to send it back. After talking to some people who know transistors, I was able to repair it myself.
So, patience may be a virtue, I have no use for Bob. I'll stick with AES. After all, in this case you get what you pay for.

BTW, I found another reliable source for tubes: http://www.radiotubesupply.com/index.html His name is Roy. He's fast and has a good stock. You may want to give him a try.

[Ron Ramirez]

Okay, so he tried to do you a favor but found that he had more on his plate than he could handle. This is why I no longer do radio repair, and have more recently quit rewinding coils. Bob probably should not have taken on the signal gen, especially since he does not advertise such services.

Next time I suggest finding someone who repairs/restores test equipment. And if the person is very good at what they do...you won't get it back in a couple days. The better repair people usually have a several month backlog.

[marty]

Hi All;
I get my Tubes from Vacuum Tubes Inc and Jim has been good to me and I get them in a timely manner.. I don't know How His prices compare to the others that have been listed.. But, I am satisfied with His Service and Delivery..
THANK YOU Marty