Tube Help With Bogen Amp

[DKAudio]

Hi, My Dad has a Bogen MX30 amp. I am going to put all new tubes in it for fathers day. It has been sitting in the basement for years and we just finished a new cab and am going to use this for the head.

It has 12AX7s, 6L6GCs and one other kind but I can't remember off the top of my head. I want to order everything from thetubestore

For the 12AX7s I was thinking of the Tung-Sol

For the 6L6GC I was thinking of the Sovtek 6L6WXT+

I can't spend much more than that. Good idea or do you recommend another kind for that amp?

If anyone knows the other tube that I can't think of that would be great.

Also, when I opened up the amp I noticed 4 metal socketed devices with the notation of X1, X2, X3 and X4 printed on the amp frame. First, what are these? Secondly the X3 spot is empty and has some jumper wires soldered together out of the socket holes. It looks orignial but was wondering if this is the way it is supposed to be?

Thanks

 

[domct203]

I recommend you contact Doug Preston at www.Dougstubes.com

Shoot him an e-mail telling him the make and model of the amp, and the desired performance (tone) from it. He sells many different brands of all kinds of tubes, and has proven (to me) to know his sh*t. He'll give you some suggestions.

Dom

 

[DKAudio]

Contacted him and he suggested the Tung Sol and then the Tad 6L6SPRs. Yet to find what the 3rd type is and he had no idea what that X1-X4 component is. Still looking for an answer to that.

Thanks

 

[domct203]

I love the Tung-sol 12AX7 in V1 of my Roadster. Never tried the TAD's but I've heard good things about them.

I have SED =C= SV6L6GC in the Roadster and I like them the best so far vs. JJ & Mesa STR440 6L6's.

Good luck with the tube swapping, have fun

Dom

 

[recto-robbie]

I would highly recommend going with doug. He knows his stuff and does good business.. Those tung-sols are great. I have never tried the TAD'S you mentioned but I do own some TAD 6l6wgc's. These are really nice tubes and enjoy the sound of these more than my jj's and mesa power tubes. I would have to say from the sound of it,, doug has you going on the right path already. Good luck

 

[DKAudio]

ok, the two other tubes are a GZ34/5AR4 and a 7247.

The devices with the notation of X_ are 9 pins, pretty short and about a half dollar size round. On the top they have printing like this...

45-9305
-01

 

[Restless Rocks]

Hey DK, I don't remember any Bogen guitar amps only PA and Intercom amps. As such the nine pin sockets in question were for adding balancing transformers or impedance matching transformer modules into the input circuit. This would allow the use of either high or low impedance mics, or balanced or unbalanced line level signals. You should be able to find a schematic to the Bogen on one of the vintage amp sites. If I get time I'll hunt it up and post you a link.
John

 

[domct203]

The GZ34/5AR4 is your rectifier tube(s). This converts AC voltage to DC voltage for the power section. This tube effects the feel of the amp (sag).

The 7247, or 12DW7 is most likely the Phase Inverter tube, or the tube that drives the power section.

Hope this helps,
Dom

 

[DKAudio]

Ok, ordered through Doug, here is what I got...

(1) JJ ECC832
(1) JJ GZ34/5AR4
(2) Matching pair TAD 6L6GC-STR
(4) Tung Sol 12AX7

Total was just under $130.

Now, I need help. Is there anything I should know about replacing these? Can oils (finger prints) get on the tubes or not (like halogen lamps)? How do I bias? Biasing is only for the power tubes, 6L6, correct? Is there a tutorial? Again, I am new to tubes and want to learn and do it right so my Dad can play for years and years of trouble free service. I am getting a SAM but it is a DjVu file and I cannot open it until I get home and download a reader later tonight.

After this project I want to build a little 2-10W RMS tube amp that will have a input for a radio tuner or phono.

Restless, thanks for clarifying what those devices are. Do I need to mess with those in order to have a correct input? I hope the Schematic will tell me if the X3 spot should be missing. I noticed that they are not keyed and can do in any direction, again, hopefully the schematic will carify. There is a tap on the back for 4, 8 or 16 ohm loads (speakers I assume).

Thanks for all the help so far, I appreciate it.

 

[again with this]

Ok, ordered through Doug, here is what I got...

(1) JJ ECC832
(1) JJ GZ34/5AR4
(2) Matching pair TAD 6L6GC-STR
(4) Tung Sol 12AX7

Total was just under $130.

Now, I need help. Is there anything I should know about replacing these? Can oils (finger prints) get on the tubes or not (like halogen lamps)? How do I bias? Biasing is only for the power tubes, 6L6, correct? Is there a tutorial? Again, I am new to tubes and want to learn and do it right so my Dad can play for years and years of trouble free service. I am getting a SAM but it is a DjVu file and I cannot open it until I get home and download a reader later tonight.

After this project I want to build a little 2-10W RMS tube amp that will have a input for a radio tuner or phono.

Restless, thanks for clarifying what those devices are. Do I need to mess with those in order to have a correct input? I hope the Schematic will tell me if the X3 spot should be missing. I noticed that they are not keyed and can do in any direction, again, hopefully the schematic will carify. There is a tap on the back for 4, 8 or 16 ohm loads (speakers I assume).

Thanks for all the help so far, I appreciate it.

You are gonna be happy. Doug knows tubes. Not just for a nitche. Very knowledgable. I just loaded my 5150 with Tung Sol AX7s from doug.

 

[DKAudio]

I got the schematic in DjVu format. If you need this to help me bias then email me and I will send it to you. I don't know how to upload this type of file. Thanks

[email protected]