** 1970 B15N **

jbshowah · #1 08-27-2011, 04:30 PM

Do I even have to say it? What is the best way?
1 Daisy chain channels one and two.
2 Use 8 ohm external speaker out & connect another b15 cab.
3 Use external amp out and run my Rocket B100R alongside.
4 Have my tech install an xlr output on the back of the cab so the soundman can take my signal in the house (post tube, pre-eq if possible) to avoid bringing a direct box.
5 any combination of the above.
6 none of the above, rock it as is and turn all the switches and knobs up.
Appreciate any feedback from yall!
Justin

JimmyM · #2 08-27-2011, 04:43 PM

1. Try it and see if you like it. I don't do it but some people really dig it.

2. I LOVE having an identical extension cab with my 64 B-15N.

3. I know people who do similar, and it can work, but IMHO not as good as #2.

4. NEVER!!! If you absolutely have to DI a B-15N (as everyone knows, micing it with a quality mic is by far the way to go), use a separate DI that runs at speaker level, and put it in between your cab and the speaker out in your head. Countryman and Radial both make great DI's for this purpose. Never cut into your B-15 for any reason unless it's a safety hazard or it isn't working.

5. Experiment around and see what you think.

6. That's as good a way as any to play a B-15.

Congratulations for joining the elite!

Alex1984 · #3 08-27-2011, 11:52 PM

Join the Portaflex Club while you're at it!

coreyfyfe · #4 08-28-2011, 06:41 AM

If you have an "extension amplifier" jack on there in addition to the extension speaker you could always plug that into a DI to go FOH. That signal is meant to go into the ext amp jack or input of another amp or be used as a DI for mixing so it should be the appropriate level (meaning it's not speaker level) but I think it's post EQ.

77PBass · #5 08-28-2011, 06:59 AM

Quote:

Originally Posted by jbshowah

4 Have my tech install an xlr output on the back of the cab so the soundman can take my signal in the house (post tube, pre-eq if possible) to avoid bringing a direct box.

Not advisable...it will destroy the value of the amp and is unnecessary. Use a Countryman DI if you must...the best thing to do is like Jimmy says, buy a quality mic and use that.

jbshowah · #6 08-28-2011, 07:04 AM

Thanks for the advice! There is a good condition identical extension cab (without the amp) on ebay right now, so I think I will look at it. What do yall think is a reasonable price to pay for the cab?

Mic'ing the amp is ideal, but knowing about the direct signal will give the soundman more ability to blend the 2 signals. It makes good sense to put it in between the amp and the cab .. had not thought of that. Also, good to know that the external amp out provides another option for that purpose.

It helps the volume when I prop the amp up on a wood block. Has anyone ever found a good kickstand substitute to put behind the amp since this model does not have a place for the ampeg kickstand?

coreyfyfe · #7 08-28-2011, 07:28 AM

Not sure on the going price of an original cab, but the repros from fliptops run around $4-500 unloaded. I think the vintage blue repro double baffle cabs are around $750 so I guess keep that in mind.

77PBass · #8 08-28-2011, 10:37 AM

Quote:

Originally Posted by jbshowah

Also, good to know that the external amp out provides another option for that purpose.

It may be your only option for a pre amp out for DI. I am not sure but the 1970 model may still have the OT protection circuit that uses the XLR looking, hard wired speaker wire from the head to the cab. If that is the case, you can't put a DI capable of speaker loads between the amp and the speaker without alteration.

coreyfyfe · #9 08-28-2011, 02:36 PM

Quote:

Originally Posted by 77PBass

It may be your only option for a pre amp out for DI. I am not sure but the 1970 model may still have the OT protection circuit that uses the XLR looking, hard wired speaker wire from the head to the cab. If that is the case, you can't put a DI capable of speaker loads between the amp and the speaker without alteration.

You can do it with the older models if you use the 4-pin/1/4" connectors, but it does add an element of bulkiness to the whole operation.

jbshowah · #10 08-28-2011, 10:57 PM

Man, you guys answer my questions before I ask them .. I was going to say it is a 1969 or 1970 model and has an XLR output going to the cab. So, not sure how to hook up my direct box. BUT .. there is also a 1/4" female output beside the XLR one. My tech said this 1/4" output does not appear on the schematic I provided (1969 B15N from fliptops.net) and he thinks someone added it later. I'm still not sure which way to go with it .. could I use both 4-pin and 1/4" at the same time (one for cab, one for direct box), and if so, could I use a regular ol passive direct box that won't break me if it breaks on a gig or somebody steps on it or spills a beer on it?

JimmyM · #11 08-29-2011, 12:11 AM

You can buy 4 pin XLR to 1/4" adapters from Welcome to Fliptops -- Parts for Ampeg and other Vintage Amp Lovers . And as long as it says you can use it for a speaker out DI, then you can use it. Just remember it does not take the place of a cab, and you still have to have a cab plugged in to keep your output transformer from blowing.

As for a kickstand substitute, I used to take the dolly off and put a piece of wood under it. But that is a giant PITA, so I'd say get a heavy duty amp stand instead. Or just buy that extension cab on Ebay and stack them.

coreyfyfe · #12 08-29-2011, 05:58 AM

Quote:

Originally Posted by jbshowah

Man, you guys answer my questions before I ask them .. I was going to say it is a 1969 or 1970 model and has an XLR output going to the cab. So, not sure how to hook up my direct box. BUT .. there is also a 1/4" female output beside the XLR one. My tech said this 1/4" output does not appear on the schematic I provided (1969 B15N from fliptops.net) and he thinks someone added it later. I'm still not sure which way to go with it .. could I use both 4-pin and 1/4" at the same time (one for cab, one for direct box), and if so, could I use a regular ol passive direct box that won't break me if it breaks on a gig or somebody steps on it or spills a beer on it?

If it's labeled extension speaker then it's stock and you shouldn't plug into that unless it's connected to a speaker load. These amps, as with the V4, SVT, etc used special jacks that tripped the different windings on the output transformers depending on which was plugged in. You have to use the main out for 8 ohm, plugging anything into the second jack will switch you over to the 16 ohm tap. If you look at this schematic, it's the one labeled ext. spkr.

If you're going to plug it into a standard passive direct box, use the "ext. amp" jack only. If you're using a speaker level direct box, use it in-line with the 4-pin plug (with adapters) unless you get the second cab, then you could just go inline with the second cab.

Edit - found the technical info regarding what I was saying from one of our resident tech experts:

Quote:

Originally Posted by beans-on-toast

To use just the EXT SPEAKER jack alone, you need to have a dummy plug (a 1/4" plug with nothing connected it to) inserted into the SPEAKER jack.

It is a good thing to have what is called a shorting jack installed inside the amp for the SPEAKER output. It protects the amp in case it is turned on without a speaker cable and cab connected. Some SVT's do not have a shorting jack for the SPEAKER out. These don't need the dummy plug. On SVT's that have a shorting jack, you need to insert the dummy plug. Otherwise just plugging into the EXT SPEAKER will put a short across your speaker cabinet and make the tubes upset. Since you can't tell what type of jack you have installed, best to always use the dummy plug.

I know my SVT and V4 were this way, and as far as I know, the B-15s of the same era were done the same way.

jbshowah · #13 08-29-2011, 10:20 AM

This 1/4" output is beside the XLR line and it is unlabeled. It is separate from the external amp and external speaker out. Is this stock?

77PBass · #14 08-29-2011, 10:25 AM

Quote:

Originally Posted by JimmyM

You can buy 4 pin XLR to 1/4" adapters from Welcome to Fliptops -- Parts for Ampeg and other Vintage Amp Lovers . And as long as it says you can use it for a speaker out DI, then you can use it. Just remember it does not take the place of a cab, and you still have to have a cab plugged in to keep your output transformer from blowing.

That's a $50 + proposition.....maybe better, cheaper solution below...

Quote:

Originally Posted by coreyfyfe

If you're going to plug it into a standard passive direct box, use the "ext. amp" jack only.

If you use a Countryman (every bassist should have this in his bag 'o tricks) you can use it for either line level or speaker level load. While there are better (re: more expensive) DI's, the Countryman is kind of a de facto standard. I whip one out (i like to use my own since I know the battery will be fresh) and invariably the sound tech says "cool." The Countryman is kind of like a Leatherman multi-tool for musicians.

=

JimmyM · #15 08-29-2011, 10:28 AM

The ext jack out is only the preamp, and not the power section and output transformer. It should still sound great, but through the speaker out will sound even better IMHO.

77PBass · #16 08-29-2011, 10:38 AM

Quote:

Originally Posted by JimmyM

The ext jack out is only the preamp, and not the power section and output transformer. It should still sound great, but through the speaker out will sound even better IMHO.

Absolutely. IMHO and the opinion expressed in the "Ampeg Story" book is that the magic of Ampeg owes a lot to the power section of its bass amplifiers.

Many on TB have praised the SVT 7 Pro, with its class D power section for achieving a close facsimile of the classic sound. I want to get to GC and hear one. I recently got a used WAS because I felt it had that "output tube compression" sound I love in my V4B.

coreyfyfe · #17 08-29-2011, 10:55 AM

Quote:

Originally Posted by jbshowah

This 1/4" output is beside the XLR line and it is unlabeled. It is separate from the external amp and external speaker out. Is this stock?

That doesn't sound like it's stock. I'd look into the wiring on that then. I know some people have modded these amps over the years to get rid of the stock 4-pin so maybe a parallel connection to the 8 ohm OT tap was made, defeating the standby circuit in the 4-pin system. Definitely worth having a tech check out.

Quote:

Originally Posted by 77PBass

If you use a Countryman (every bassist should have this in his bag 'o tricks) you can use it for either line level or speaker level load. While there are better (re: more expensive) DI's, the Countryman is kind of a de facto standard.

+1 on the the country man. I usually bring mine with me on most gigs and get the "well someone came prepared" type comments as well.

JimmyM · #18 08-29-2011, 10:59 AM

When I was using a speaker out DI (I tried to make peace with it, I really did), I used to get the same comments from bringing the Countryman. I also got the occasional ball buster who tried to make me go straight in from the bass. I would politely refuse, and one time not so politely. It just sounds so much better from the speaker out to me.

coreyfyfe · #19 08-29-2011, 11:23 AM

Quote:

Originally Posted by JimmyM

When I was using a speaker out DI (I tried to make peace with it, I really did), I used to get the same comments from bringing the Countryman. I also got the occasional ball buster who tried to make me go straight in from the bass. I would politely refuse, and one time not so politely. It just sounds so much better from the speaker out to me.

I think the most ball busting I got was a gig where I brought my PR40 and had it set up and ready to go and the sound guy said "oh I guess we're mic'ing the bass". The first time I played that room I brought the SVT (to a few wiskey-tango-foxtrot looks) since I didn't know what to expect and I don't think I had the volume above 9 o'clock all night. I come back with the B-15 ready to play nice and go through the FOH and that's the attitude I get in return.

77PBass · #20 08-29-2011, 11:24 AM

Let's face it, DI with a separate speaker DI or cab mic is the preference.

I recently did a gig and the sound guy was happy to see the DI on my BT500. I said let's not use that and use the CM instead. I wanted to put it between the amp and the speaker but in my rush and absentmindedness, I went into the instrument input (we were the opener and the headliner was an insane female jazz trumpeter who ragged on the sound guys and thought soundcheck meant rehearsal).

Anywho, I played direct from my '65 JB to the board...which they recorded and darn it, they did a fantastic job. It certainly sounded different than on stage but they did a pro job and I thanked 'em for it.