Dynaco Dynamax Speaker Stacking Manual :)

[Dynacophil]

Dynaco Dynamax Speaker Stacking Manual

Dynamax_small.pdf

[Dynacophil]

Dynaco Dynamax Speaker Stacking Manual

if anybody wants a a higher Quality.pdf (3-4mb) pm

[mr.b]

Thank-you for posting this but I need some clarification. If I wish to wire pair of speakers, do I use the example provided on pg.2? If so, what is the significance of the 4ohm notation by that image? The A25's and A35's I want to pair up are all 8ohm speakers. Does hooking them up in the fashion suggested change the effective ohm rating of that pair? Pardon me if the questions are elementary. Hope you or someone else can assist.

[dynaco_dan]

Thank-you for posting this but I need some clarification. If I wish to wire pair of speakers, do I use the example provided on pg.2? If so, what is the significance of the 4ohm notation by that image? The A25's and A35's I want to pair up are all 8ohm speakers. Does hooking them up in the fashion suggested change the effective ohm rating of that pair? Pardon me if the questions are elementary. Hope you or someone else can assist.

Hi there;

Don't worry if your questions are elementary or not, they're really good questions.

Each of the Dynaco classic speakers, A-10, A-25, A-35 and the A-50 are individually factory rated 8 ohm systems.

The impedance swing, high to low, of each of these speakers, is much less than the typical acoustic suspension or bass reflex designed speaker system.

In other words, a fairly ruler flat impedance curve, compared to any other type speaker system.

The impedance is pretty close to 8 ohms, from the lowest to highest reproduced notes and is a good match for an 8 ohm output amplifier.

Dynaco felt it was not an issue to parallel a pair of their speakers to give a safe 4 ohm load.

If you have a pair of speakers in parallel now and your amplifier has a 4 ohm tapping, this is the best one to use.

An AR-3A speaker, for one example, goes from one extreme to another, less than 2 ohms to over 35 ohms, stressing out the capabilities of the very best of amplifiers.

Those two added sheets make adding more sound output from Dynaco speakers from a much more safe, factory approved schematic, rather than us just guessing.

Vern

[dynaco_dan]

Hi there;

Don't worry if your questions are elementary or not, they're really good questions.

Each of the Dynaco classic speakers, A-10, A-25, A-35 and the A-50 are individually factory rated 8 ohm systems.

The impedance swing, high to low, of each of these speakers, is much less than the typical acoustic suspension or bass reflex designed speaker system.

In other words, a fairly ruler flat impedance curve, compared to any other type speaker system.

The impedance is pretty close to 8 ohms, from the lowest to highest reproduced notes and is a good match for an 8 ohm output amplifier.

Dynaco felt it was not an issue to parallel a pair of their speakers to give a safe 4 ohm load.

If you have a pair of speakers in parallel now and your amplifier has a 4 ohm tapping, this is the best one to use.

An AR-3A speaker, for one example, goes from one extreme to another, less than 2 ohms to over 35 ohms, stressing out the capabilities of the very best of amplifiers.

Those two added sheets make adding more sound output from Dynaco speakers from a much more safe, factory approved schematic, rather than us just guessing.

Vern

Hi again;

I looked at those two sheets again and thought of something else.

Dynaco mentioned how compatible all of those speakers are with those connections and power handling capacity if using a Dynaco 400 power amplifier.

Almost indestructible speakers?

What are the fuse size suggestions in this case, with a Dyna 400?

Remembering that the drivers are not available direct from Dynaco anymore.

Fusing each speaker separately?

Fusing each complete channel of speakers?

What if you only have a Dynaco Stereo 120 amplifier or something even smaller and not a Dynaco Stereo 400?

I can just see a Dynaco SCA-80Q integrated amplifier, or equal, running out of steam and clipping with loud music passages.

This is where it would be nice to have some of the Dynaco inter-office memos, technical notes or engineered drawings.

[dynaco_dan]

Dynaco Dynamax Speaker Stacking Manual

Hi there

I just came across a printout of this article today in my literature collection.

After all this time has passed I could not remember where my copy came from.

I went to the web and typed the full article heading line in and up popped, "Audio.Asylum.com" and additional letters and numbers, path.

I went there to look at it again.

I did type it in as per listed address and I hit a deadend.

I did several searches there and had only been able to find 200+ prospective hits.

Never did find this particular article though.

When I came back here, to CSP, to the Dynaco section, I did a search for, "Dynamax" only and here we are.

I did a search here just for the heck of it, I was not expecting it to be from here, what a nice surprise for today.

After all this time, I wish to again thank you very much for posting it here.

Actually this article should be posted in the library under, misc or ?, as it is archival information, it's not going to be

changed, uodated or amended by Dynaco.

It is also applicable to more than just Dynaco 8 ohm speakers IMO.

Is a higher resolution photo available by chance?

[dynaco_dan]

if anybody wants a a higher Quality.pdf (3-4mb) pm

Hi there

I would appreciate a higher resolution copy, thank you.

[thechatterboxman]

Hello--

I realize this is an old thread, but I would love to have a better copy of this literature if it is still possible to get a copy. I knew Dynaco sanctioned stacking their speakers, but I didn't know they had a design to keep the impedances from dropping so drastically.

Any response would be appreciated.

Randy

[dynaco_dan]

Hello--

I realize this is an old thread, but I would love to have a better copy of this literature if it is still possible to get a copy. I knew Dynaco sanctioned stacking their speakers, but I didn't know they had a design to keep the impedances from dropping so drastically.

Any response would be appreciated.

Randy

Hi there

The original Dynaco A-25 was designed to have a more linear woofer impedance using the patented Aperiodic system.

There was lot's of Dynaco literature clearly explaining this design.

The woofer did not go appreciably below the 8 ohm speaker impedance rating, compared to acoustic suspension or bass reflex speaker systems.

The theoretical use of a pair paralleled should be a relatively safe 4 ohms or there abouts.

I don't remember reading of another manufacturer making a similar claim.

Anyone using another brand of 8 ohm speaker is taking a chance that the impedance will be suitable.

As usual, about fusing, individual speaker fusing is all the information we have to use at this time.

The A-10, A-35 and A-50 may or may not have as smooth a load for the amplifiers, or mismatching these models

even.

I will soon be posting an old A-25XL, a very confusing review, which states that the tweeter used in it will

have too low an impedance for recommended paralleling.

[craig]

Wow amazing post. It reminds me of a old huge apartment i had. I used 4 channel dynaco A25's and due to the room being so large they just enhanced each other even in the bass, I didn't even need a sub woofer the highs and mids were also amazing, overall it was the best sound set up i ever owned or heard, sounds great in my new place as well but i only use 2 channel sound here , the lay out and live nature of the room, sound pretty good with just one pair. In the correct room A25 4 channel sound can be quite a mind blowing experience. I noticed in the post they suggest some pretty powerful amps, i use a rotel 125 wpc amp, how much can A25's handle power wise ?

[dynaco_dan]

Hi there

The amplifier to use with the Dynaco A-25 is as follows.

Rated at 8 ohms continous is best.

Dynaco gave the A-25 a 60 watt rating of sorts.

Reading the following should give you more insight, I hope.

For casual background up to moderate loudness usage maybe 25+ watts per channel.

Using up to 100 watts per channel is about the safest ceiling level.

Obviously the type of music, speech or frequency testing will determine it's extreme usage.

Using a Dynaco recommended 1 amp glass fast blow fuse, per speaker, with an open style fuseholder, offers the safest usage.

I am certain some have been used with 10 watt or smaller amps and even Phase Linear 700's without damage.

The likelihood of damage is greater with accidents than anything unless terribly overdriven.

Disconnecting low or high level cables while using is likely the most common failure, with exception to high level rock music.

A long drawn out signal such as, a partial poor ground cable connection, a signal generator signal too loud and too long in duration, etc.

Without fuses or other safety device installed,the over load heats up the cable from the amp to the speaker voice coil.

The voice coil insulation can heat up causing bubbling of the coil wire insulation, thereby bubbles get larger and eventually start rubbing in the voice coil gap.

The voice coil form starts to discolour and char and eventualy becomes toast.

Distortion or a small buzz is audible and if left as is will become worse, until just silence.

This is not exclusive to Dynaco drivers but I have seen far too many A-25 woofers and the damage is cumulative and non repairable.

With my comments you should understand that there is no, carved in stone, amplifier suitable rating.