Replacement 15" 16ohms speaker for 1964' Dynacord cabinet

[agedhorse]

It’s not original anymore, it has been replaced in the past by a somewhat newer model, so it’s possible that I might be able to change the output impedance from the OT. If that’s the case then it’s good news, but it’s still a compromise because I won’t be able to use the cab with all of my amps. But frankly if I have to buy a proper OT + 1 speaker, it’ll cost me more than I paid for the whole thing in the first place.

@agedhorse it depends on what you mean by mediocre performance? The cab is from 1964 and I’m pretty sure that the way it left the factory would be considered somewhat mediocre by today’s standards…The amp it came with has 3 EQ settings presets for guitar/bass/vocal microphone, that gives you an idea of what the original purpose of this amp was…
If I wanted to use the cab live playing bass, then I would probably be more careful with my choice of driver but in my case, the room is well treated and I just need a not-too-powerful speaker that sounds good with electric bass while being recorded with vintage mics and preamps.

True, everybody has a different definition of mediocre. I would hesitate spending much money on mediocre results myself...

Google mentions these (AI-search, so may be untrue in any or all ways...)

Here are the best options for a 16-ohm 15" bass speaker:

1. Eminence Delta-15B (16 Ohm)

• Best For: All-around, powerful, modern bass tone.
• Power: 400W RMS / 800W Program.
• Suitability: Excellent for both sealed and vented enclosures, and specifically noted for musical instrument systems.
• Availability: Widely available from online retailers like Adorama, Walmart, and specialty audio shops.

2. Celestion G15V-100 Fullback (16 Ohm)

• Best For: Vintage tone with added weight.
• Power: 100W RMS.
• Suitability: Designed for 15-inch combos, offering an extended low end, warmer mids, and a "contralto growl" when overdriven.
• Availability: Available through online retailers like Amazon.

3. Jensen Vintage C15N (16 Ohm)

• Best For: Vintage Fender-style warmth and definition.
• Power: 50W RMS.
• Suitability: Ideal for vintage bass amps, offering a tight low-end and clear, punchy tones, often used in classic Leslie cabinets.
• Availability: Available through retailers like Amazon and Long & McQuade.

4. Harmony Audio HA-P15LS16 (16 Ohm)

• Best For: High-power, budget-friendly replacement.
• Power: 500W RMS / 1000W Peak.
• Suitability: Designed for high-output PA or bass, featuring a 90oz magnet for deep, resonant bass.
• Availability: Available on Walmart.ca.

Summary Recommendation

• For maximum durability and punch in a modern rig, the Eminence Delta-15B is the premier choice.
• For vintage warmth and tone, the Jensen C15N is the best alternative.
• For high-powered, modern rock, the Celestion BN15-400X (though often found in 8-ohm, ensure the 16-ohm version is sourced if specific to that impedance) is a top contender.

The Delta 15B is the best compromise, but not great. Two are guitar speakers with VERY limited mechanical power handling and poor low end, the Harmony Audio is an unsuitable sub-ish type driver w/ poor mid extension and then AI randomly pulls a previously unmentioned BN15-400X out of its butt as a top contender. The two guitar speakers are poor choices, worse then mediocre.

I was thinking about an 8Ohm 100W wire-wound power resistor in series with a nice 8Ohm 15inch speaker.
It’d affect (flatten) the impedance response curve but not the frequency curve ‘shapes’ - and you’d lose 50% of the output voltage. And it’d get potentially hot. And it might sound crap.
So - my brilliant idea is: replace output transformer and go 8Ohm (boooring!!)

Terrible idea (though it gets high marks for meritorious attempt), it will change the shape of the curve a lot and completely destroy any damping that the already low damping factor tube amp has. Replacning the output transformer is probably the second best answer after trying the Dalta 15B (which is IMO better than mediocre)

 

[byacey]

Depending on the make and model of the transformer, it may already have available taps for an 8 ohm load. A transformer wound exlusively for 16 ohms seems somewhat out of the ordinary for that era.

 

[ajkula66]

Depending on the make and model of the transformer, it may already have available taps for an 8 ohm load. A transformer wound exlusively for 16 ohms seems somewhat out of the ordinary for that era.

Not for a European amp. I've got a '64 Hagstrom bass head which is 16 Ohms only, and have seen Italian stuff from the same era which also required that load.

 

[Wasnex]

Not for a European amp. I've got a '64 Hagstrom bass head which is 16 Ohms only, and have seen Italian stuff from the same era which also required that load.

Wouldn't hurt to check.

AFAIK the OP's amp is an Echo King. Non of the schematics I could find showed an output section, so no idea if the OT has one or multiple secondaries.

I found a couple of Bass King schematics as well. One version appears to be set up solely for 16 ohms, but the OT has 4 and 8 ohm taps as well. The 8 ohm tap is unterminated. The 4 ohm tap goes to the feedback loop.

The other version of the Bass King is set up for either 8 or 16 ohms, but also has a 4 ohm tap. The feedback loop is connected to the 16 ohm tap and the 4 ohm tap is unterminated.

 

[bleachboy]

@buldog5151bass that's a good point, the reason I'd like to put it back together is that right now it's just as useless to me as an empty casket

@mikewalker thank you for taking the time, as usual with AI it is pretty hit-and-miss but I did come across the Eminence Delta 15B as a possible option while reading some other threads here and it looked like the "least worst" option.

@EastDakota that's amazing, thank you very much for taking the time to do the math for me, I'll take a look at that Fane Axiom.

@yodedude2 That cracked me up quite a bit! The idea is to make use of an empty useless 15" cab that I have here lying around, not to reduce the size of my real estate even more

@agedhorse again, thank you very much for your priceless advice.

So the Delta 15B looks like the best 16Ohms compromise, for now.

Out of curiosity, in case I decide to look into the OT to see if it has 8Ohms taps available, what would be a good option for an 8Ohms driver ? My Dynacord Echo King amp has three speaker output jacks. All 16Ohms, with the third one being a switched speaker output (it bypasses the main speaker out). Ideally, if the OT permits it, I would wire an 8Ohms output from the OT to one of the alternate speaker output jacks so I could use this head with 16 or 8Ohms cabs if I want to. But that still wouldn't solve the issue of not being able to use my Defiant & Bassman heads with the 15" cab, and I'm really not up to modifying the output taps of those amps (especially the Defiant which is in absolutely mint condition). The Bassman is a 6às Italia knock-off, I'm not sure it has the available taps on the OT but I'll check.

@Wasnex here's the schematics of a Dynacord King (exact same amp, without the integrated tape echo). The only issue is that the OT is not original, it's a Hammond 1750U. However it does look like there's an unused 8Ohms tap.

 

[TheSpinDoctor]

A review of the US Speaker website turned up these speakers:

FAITAL PRO 15FH520 available in 16 ohms, for front loaded ported cabinets
BEYMA 15WR400 available in 16 ohms, no mention of sealed or ported cabinet
Jensen has the C15N and C15K 15" guitar speakers available in 16 ohms.

The Beyma 15WR400 appears to be your best option.

 

[byacey]

Using the 8 ohm tap will give you access to far more suitable drivers to choose from.

 

[OldogNewTrick]

for sealed cabinets there seems to be no alternative suitable 16Ohm 15" driver other than the aforementioned Eminence DELTA-15B 16Ω.
16 Ohm 15" drivers suitable for use in sealed cabs

Delta-15B in a sealed box 76x41x23 cm


however, if you rewire your OT to 8 Ohm, your options are much greater
8 Ohm 15" bass guitar drivers suitable for use in sealed cabs, I would be tempted to use the Celestion PULSE15 for your application.

 

[Wasnex]

it's a Hammond 1750U. However it does look like there's an unused 8Ohms tap.

? AFAIK, the label indicates 4, 8, 16 ohms with 1700 ohm primary.

From the product page:

 

[agedhorse]

A review of the US Speaker website turned up these speakers:

FAITAL PRO 15FH520 available in 16 ohms, for front loaded ported cabinets
BEYMA 15WR400 available in 16 ohms, no mention of sealed or ported cabinet
Jensen has the C15N and C15K 15" guitar speakers available in 16 ohms.

The Beyma 15WR400 appears to be your best option.

Except for the fact that the Beyma is strongly designed around a ported cabinet application.

for sealed cabinets there seems to be no alternative suitable 16Ohm 15" driver other than the aforementioned Eminence DELTA-15B 16Ω.
16 Ohm 15" drivers suitable for use in sealed cabs

Delta-15B in a sealed box 76x41x23 cm


however, if you rewire your OT to 8 Ohm, your options are much greater
8 Ohm 15" bass guitar drivers suitable for use in sealed cabs, I would be tempted to use the Celestion PULSE15 for your application.

That's pretty much my conclusion too. The Delta 15B wasn't readily available retail until recently, but now that it is, it would be the obvious choice for 16 ohm needs.

The Pulse 15 is more optimized for a ported cabinet, but will be passable in a sealed cabinet.

 

[bleachboy]

Yep, I can grab a Delta 15B for around 110€ here, sounds like a good deal (at least it's less expensive than the amp)!

 

[rickdog]

If 8 ohms is an option - what about the Eminence Legend BP1525? Your box is only a little (10%) smaller than the "Medium Sealed Bass Guitar or PA" reference design.

And it's a tube amp, it shouldn't mind a load that's a little lower than nominal, especially if it's not being driven hard.

 

[bleachboy]

For now it seems the

? AFAIK, the label indicates 4, 8, 16 ohms with 1700 ohm primary.

View attachment 7449896

From the product page:
View attachment 7449898

Sorry, wrong choice of words from my part!

For now I think I'll go with the Delta 15B, it seems like the best compromise for my use. That way I can plug all of my amps and cabs into the Kayahan 8 amps/4 speakers rackmount midi switcher and not worry about impedance mismatch. If in the future I want to try another driver in 8Ohms I'll know some good options!

 

[crobasster]

In the 90's my power trio used this amp, but we had other Dynacord speakers , two columns with 2x12' and 3xtweeters ! They were old Fender-Jensen !

 

[bleachboy]

Ooh the plot thickens ! Were they more modern speakers cabinets or were they from the 60´s ?

 

[OldogNewTrick]

The Pulse 15 is more optimized for a ported cabinet, but will be passable in a sealed cabinet.

Pulse 15 has a fS of 35.1 Hz / QES 0.47 -> EBP 74,7 => sealed and ported
LEGEND BP1525 has a fS of 32 Hz / QES 0.5 -> EBP 64 => sealed

However as a full range driver in a vintage oriented cab I prefer the higher frequency extension and tone profile of the Pulse 15.

But a moot point, since 16 Ohms is required...

 

[agedhorse]

Pulse 15 has a fS of 35.1 Hz / QES 0.47 -> EBP 74,7 => sealed and ported
LEGEND BP1525 has a fS of 32 Hz / QES 0.5 -> EBP 64 => sealed

However as a full range driver in a vintage oriented cab I prefer the higher frequency extension and tone profile of the Pulse 15.

But a moot point, since 16 Ohms is required...

Right, but they are not really great choices for sealed cabinets, they are a compromise in that they work “ok” but give up performance in either application. The Legend may work better in a sealed cabinet, but maybe not. That may be an ok tradeoff, but that’s also a judgement call.

Of course the 16 ohm requirement makes it a moot point.

 

[crobasster]

Ooh the plot thickens ! Were they more modern speakers cabinets or were they from the 60´s ?

Of course, vintage from 60's !

I will post a photo, still have them somewhere around !

 

[bleachboy]

That would be great, thanks !

 

[bleachboy]

Hi ! Since I have ordered the Delta 15b, it turns out that the speaker might take approx. 2 weeks before it's shipped and it has got me thinking...I'm planning on adding these two units to my studio setup as soon as funds permit :

ACS 8×4 - Amplifier Cabinet Switcher — KHE Audio | Amp Cab Switchers

The KHE ACS 8x4 amp switcher lets you select and play all your heads and cabs instantly, in any combination, by a single push of a button. Instant A/B testing and amp shootouts!

www.khe-audioelectronics.com

KHE ZMX - Automatic Impedance Matcher for ACS Amp/Cab Switchers — KHE Audio | Amp Cab Switchers

The ZMX is an automatic impedance matching device for the KHE ACS Amp/Cab Switchers. It is designed to eliminate impedance mismatches between the amps and cabs in the ACS system (speaker-level signals). Automatically, safely, and transparently.

www.khe-audioelectronics.com

The first one is a 8 amp > 4 cabinet switcher, the second one is an automatic impedance switcher that plugs into the loop of the aforementioned amp/cab switcher. It basically matches any amp impedance with any speaker impedance instantly. That would definitely solve a lot of my problems, I could wire the OT speaker out of my Dynacord amp to 8 ohms, buy a 8ohms driver to put in the cab so it's safe to use directly with the amp, and ultimately since everything is going to be connected to the switcher I will not run into impedance mismatch between my amps and speakers.

Therefore, I could maybe cancel my Delta 15b order and look for a 8ohms speaker instead, which all of you said would give me a wider choice for a bass cabinet. Does that make sense ? In that regard, would the Beta 15A be a better choice ?

Thanks !