Matched and lovin it

[Enochrome]

I took an inventory of the tubes. There are:
1 = 12ax7,
4 = 6BA6
4 = 6BMB (which i believe is for the amp),
1 = big 5AR4 (power output?)
2 = 6BE6 ( part of the phone section?),
2 = 6A9(?)8

The 12AX7, 1 6BE6, and 1 6BA6 are not lighting up. One of the 6BMB looks like it is running hotter than the others.

Are the 12AX7 and the two 6BE6 part of the phono section? By the way, is it dangerous to mess with these tubes?

[poppachubby]

Not sure. What's the amps model number again? Are you a member of Audiokarma? Might be a good idea to join there or at the Tube/Vintage Asylum. Both have great forums with knowledgable members.

I'm not familiar with some of those tubes, therefore the topology is baffling to me. Give me the model number and we'll find something.

What do you mean by mess with them? Taking them out is no problem at all. In fact, you will want to clean the pins on any you plan to use. Use that Deoxit you love so much.

[Enochrome]

Pioneer SMB-200A. I could not find much online. I found info on most of the tubes except the 6BE6. I read online a couple of times that you should be cautious when handling tubes because of the voltage.

[Enochrome]

I tried running it through the tape outs and it worked, but it did not have any warmth to it or much power, which I think is due to the absence of the 12AX7. I still get sound, while the 12AX7 is not lighting up, so I assume that some of the other tubes are doing the work. It sounded very clinical and flat.

[poppachubby]

Eno, you should pay a tech for a diagnosis at the very least. Well worth it.

[Enochrome]

Good advice. I think I am going to over to Brooks Brendan, and have them take a look, they are building a hi-fi museum, so they should know.

Do tubes generally give you a more flat tone with a little warmth or a completely warm and smooth sound? Maybe I am not use to the sound, since I have never heard hi-fi tube audio, besides guitar amps.

[poppachubby]

Generally really smooth and warm mids. Depends on topology, and I'm not familiar with yours. For example my Golden Tube is very detailed with exceptional mids. This extends to the upper bass and lower highs, it rolls off in the extreme dynamics. I have heard some Eicos and Dynacos which fall short on detail compared to the SE40.

Take it in and get the run down. You need to know what each tube is doing in the circuit. Most definitely find out which pre tubes are driving the low gain output. Those are the ones you'll want to replace with something nice.