Ampeg B15n Rebuild

[dustinymichaels]

I'm 57 years old, have dealt and beat stage 3 colon cancer in the last 2 years and have decided to rebuild and USE all my old amps. Just finished a 58 Princeton (OMG...the tone) and now I'm working on a 1969 Ampeg B15 that I bought from a dude who never played it. It's absolutely mint which makes me nervous to take out to gigs but then I only play nice places and bigger gigs now...so questions.

I've settled on an Eminence Beat15 for the speaker but now I'm looking to see what tube set I should buy. Everything in this amp is 100% original so I want to keep all that and play updated and more reliable parts. Money isn't really an issue but at the same time, I'm married and own 35+ basses so I have to make my wife happy and so I'm trying to balance what makes sense. Also, what mic so you suggest using? I usually run 2 channels, a direct line and a mic'ed line. I have beta52, audio D6 and a few other options in my studio...just don't know what works live. Suggestions welcome.

Cancer makes you rethink everything. I've collected and held on to gear for years, now is the time to use it, but I'm not stupid, everything is very protected.

Thanks for your help and suggestions on this.

Congrats on beating the fight. I just lost a buddy in December, fellow musician, age 48. Whatever you do, keep rocking.

 

[Short4since64]

You may not have read this post. The audio files are helpful.
https://www.talkbass.com/threads/am...altec-421-jbl-d140-cts-square-magnet.1448590/

This is the schematic for a late 19860's B-15N. The external amp output gives you the option to send a post-pre-amp signal to a mixer or recorder, allowing you to keep that signature Ampeg tone.

Again, congratulations on beating cancer. And congratulations on resurrecting such a fine amplifier.

That's not the schematic for a '69. The late '60s B-15Ns were fixed bias and used a 5AR4/GZ34. For a speaker, you might want to check with Vintage Blue to see if a rebuilt original square-magnet CTS is available. The Altec 421 also works well in this cabinet and will still allow the head to flip and fit, and give you a few dB more to boot. These amps were built like Mack trucks, used quality components really do not degrade. If the primary filter capacitors are not leaking / swollen, and the amp doesn't hum it is probably working just fine. If it aint broken, don't fix it. Install a 3-wire cord, disconnect the ground switch and death cap, enjoy this fine piece of engineering. Best luck to stay cancer-free permanently.

 

[Hoochie Coochie Man]

Hort Elvison.

Take a look at the portaflex wiki here: https://www.talkbass.com/wiki/ampeg-portaflex-wiki/ for a lot of good information.

 

[Hort Elvison]

Hey @Hort Elvison, congrats on beating your cancer. I am a late stage (4a) colon cancer survivor myself ... 22 years now. I TOTALLY get your statement that survival changes everything ... and hopefully for the better. Certainly made me re-evaluate a lot of things in my life and guided me to go back to things that really mattered in life. It may be kind of an odd thing to say, but I tell people who ask, that once my survival was clear, that I felt like cancer was a gift to me as it made me rethink what really mattered in life. FWIW, music became much more important to me and remains to this day.

I got nothing on your B15 question, but good luck and good living!

Thank you. You said it better than I did - it has been a gift. My life is 1000% better, I’m more focused and the crap in my life is gone (no pun intended). Congrats on your survival…I will survive mine as well.

 

[Hort Elvison]

That's not the schematic for a '69. The late '60s B-15Ns were fixed bias and used a 5AR4/GZ34. For a speaker, you might want to check with Vintage Blue to see if a rebuilt original square-magnet CTS is available. The Altec 421 also works well in this cabinet and will still allow the head to flip and fit, and give you a few dB more to boot. These amps were built like Mack trucks, used quality components really do not degrade. If the primary filter capacitors are not leaking / swollen, and the amp doesn't hum it is probably working just fine. If it aint broken, don't fix it. Install a 3-wire cord, disconnect the ground switch and death cap, enjoy this fine piece of engineering. Best luck to stay cancer-free permanently.

Great advice. I will look into these and yeah, death cap goes. Did that on the Princeton too.

 

[Hort Elvison]

Thanks all, I didn’t expect all the responses about my cancer battle but I really, really appreciate them. Makes me feel less alone in my experiences which is nice but it also alarms me how many bass players have fought cancer. Maybe we should have picked another instrument?!?

 

[TheSpinDoctor]

That's not the schematic for a '69. The late '60s B-15Ns were fixed bias and used a 5AR4/GZ34. For a speaker, you might want to check with Vintage Blue to see if a rebuilt original square-magnet CTS is available. The Altec 421 also works well in this cabinet and will still allow the head to flip and fit, and give you a few dB more to boot. These amps were built like Mack trucks, used quality components really do not degrade. If the primary filter capacitors are not leaking / swollen, and the amp doesn't hum it is probably working just fine. If it aint broken, don't fix it. Install a 3-wire cord, disconnect the ground switch and death cap, enjoy this fine piece of engineering. Best luck to stay cancer-free permanently.

Thank you. I miss read the OP as late 60n, not late 60s. This is a better schematic.

 

[Jim C]

Congrats on your fight!
I have had the best results with a B-15 (and electric bass) with a RE20 or 2nd choice a 421. For upright I prefer a U-87 and no amp but have mic'd the amp for a slightly more modern sound too.