New Dynaco Forum Hooray

[draftingmonkey]

Vern and all you other Dynaco folks,

This is great to see. Later today, after I finish my New Large Advent refoam project, I will try to post my Dynacos to the forum. What would be great is to assemble as many photos of Dynaco speakers as we can, especially the various A-25 renditions.

A question to all: should this be a Dynaco speaker page or will it include Dynaco electronics as well. In order to stick with the theme of the Classic Speaker Pages I would think speakers only other than a mention of what we drive our Dynacos with. Something to think about.

Congrats to all, especially Vern for his devotion to get this forum up.

James

[administrator]

Hi James,

As far as I'm concerned, this forum is anything goes - as long as the topic has to do with Dynaco products, of course.

Mark

[Guest denmarkdrivers]

wooo hooo a dynaco forum !!! who Designed the drivers for the dynaco A-25s ? time after time the drivers look brand new on a 1969 pair of dynaco A 25s, can any other company of its time match the quality of thoose drivers ? because i havent found one , even new .

[draftingmonkey]

Mark,

Thanks for the clarification. This is going to be a great forum, I do believe.

James

[dynaco_dan]

>wooo hooo a dynaco forum !!! who Designed the drivers for

>the dynaco A-25s ? time after time the drivers look brand new

>on a 1969 pair of dynaco A 25s, can any other company of its

>time match the quality of thoose drivers ? because i havent

>found one , even new .

Hi there;

There is an excellent complimentary website at

http://home.indy.net/~gregdunn/dynaco/history.html

that has a beautifully laid out presentation similar to Dynaco's original brochures.

There is no updating or forum, there is a few tips regarding servicing and links.

In the speaker section, at that site, it gives credit to the original designer.

The original prototype was 4 ohms, not 8 ohms impedance.

It also credits the Dynaco man who specified the 8 ohm system.

As some may remember, Dynaco and most other equipment, of that day, was capable of it's best power output, into 8 ohms, not 4 ohms.

Scan was the earliest speaker provider, with the vent above the tweeter.

At the local Dynaco warantee depot, I saw too many Scan woofers blown, but only Seas woofers, were ever provided as a warantee replacement.

There was also some which had defective bonding of the voice coil to the voice coil cardbord form.

When it became loose, the woofers started buzzing.

Also if the bonding agent was overheatd, it started creating very small bubbles on it's surface, which caused a faint buzzing, if you listened real close to the woofer.

They can be easily identified by the Scan woofers having a round aluminum casting perimeter.

The Seas have, what I call, a horn casting projection, at each screw opening in the cast aluminum housing perimeter.

When a Scan woofer was replaced, we had to chisel a notch for the horns, in the cabinet to allow the woofers to rest in it's trough.

I do not have any memory or information, as to whether there was suppose to be any difference or not between them.

I don't remember anyone returning or questioning about the differences in woofers.

I also only remember receiving Seas repalcement tweeters, but that wasn't a signifcant problem as tweeters rarely went.

The same tweeters were used in A-10, A-25, A-35 and A-50 cabinets.

A smaller woofer was used in the A-10, using the same magnet structure as the 10" woofers.

I never saw more than, Made in Denmark or 8 ohms, stamped on the back, of the A-10's, never a label.

A-25 and A-35 used the same 10" - 8 ohm woofers, also no label, but Made in Denmark stamped on the speaker terminal plate, along with a small sticker with usually 2 numbers followed by about 8 more.

The first two are the Dynaco series number, followed by year, a single digit and week 2 digits and other numbers.

The Dynaco series numbers are listed on Greg Dunn's site.

The A-50 used 2 - 10" - 16 ohm woofers.

I never heard which version J. Gordon Holt went wild over in Stereophile Magazine decades ago, Seas or Scan.

This information was never published in any magazines articles that I ever read, and I think Dynaco would have preferred that.

If my memory serves me right, I only remember seeing Seas versions in test magazine reviews, if they removed the grill cloths.

I have seen mirror image examples on ebay where the tweeters are offset off center left and right of center.

More rambles at a later date.

[dynaco_dan]

>

>This information was never published in any magazines articles

>that I ever read, and I think Dynaco would have preferred

>that.

If different versions of the same model was visible, then some people would be leary of which version they had bought, and if it was better or worse than the other, maybe.

AR used the same old woofer in their AR-3A literature for a year or two after they had changed woofer models.

Same with AR-2AX with their tweeter and woofer change.

It was probably allowing time for stores to clear old stock as well.

The rubber or neoprene surround is a bonus, for sure.

My understanding was that Europeans did not like anything, but rubber or cloth surrounds.

No exposed driver wires, which would have deleted the AR-3, probably less so with the posts, and AR-3A, moreso with the black tape and black paint.

The A-25 is a very thirsty speaker, comparable in thirst to the AR-3A, it need lots of power to really open them up.

A simple capacitor for a crossover and a repeatable 5 position switch for the tweeter attenuation.

Not a perfect speaker, but, darn good value for the money.

Dry sounding, but if you live with it for 3 months, very enjoyable.

I haven't listened to, "Double Dynas", yet.

I also have a mismatched pair of, Scan and Seas A-25's, I bought from a regular ebay seller, that I do like and trust.

I will put these to the sound test in the near future.

I have numerous original Dynaco literature booklets, that show several different versions of, Dynaco 400 amplifiers and different A-50 baffle board locations.

I can't comment on the A-35 speaker system, but the A-50 also had different drivers, I believe Scan as well as the more usual Seas.

The tweeters by Seas used a black metal wire screen for its dome cover and Scan used a perforated or expanded black metal dome cover.

I have never compared a Seas or Scan woofer or tweeter for sound comparison.

I will assume that Dynaco would have chosen a very, very similar sounding choice to not differentiate between manufacturers in identifying at least the A-25's.

The flecked beige linen was a fairly neutral speaker cloth in its day, I have seen nothing else like it available.

In a discussion with a close friend here, dynaco sent their engineers out to the warantee depots, once a year, to show that Dynaco was supporting them.

He reminded me that, Dynaco, as well as, AR, were the very best at warantee depot support.

He remembers, Dynaco's, Ed Laurent, visiting him many years ago when he was doing the Dynaco warantee work.

This should be an easy speaker line to change caps in, heh?

Enough rambles for one day.

[dynaco_dan]

Hi there;

More rambles.

I forgot something very important when shopping for used drivers.

B&O for one other company, used Seas drivers also, but they were sometimes 3 ohms not Dynaco's 4 - 8 ohms, as per magnet stickers.

If you were to use 3 ohm tweeters, they would be a db or two higher in volume, than the stock Dynaco 8 ohm tweeters.

[Guest denmarkdrivers]

thanks for the info dan, and yes removing the covers on the A 25's is a must.... hehe covers in 1969 hated sound i guess

[Guest denmarkdrivers]

hey vern, nice discription of the A25's

I have heard dynaco's dueled and wow, only problem is you need a very big room or they will crash and not sound good at all.

My old place was very big, for years i never tried dynaco's dueled then one day i did it , amazing, in some ways it felt like i was cheating, efficiancy went away as far as being a problem, or atleast it simulated that sensation of transparency the dynacos sometimes lack at lower volume levels, sounded good low and loud when dueled in big room.

It was probally not technically great but the sound it gave was better then i have personally had any other place, then again the BW's sounded better there as well.

It's kinda funny as far as my friends go they all liked the dueled dynacos more on that set up in that room then the b&ws alone, except one of my best friends who really likes the b&w's,(630i).

Biggest drawback was it did not make the dynacos great LP speakers, at least not with my amp, even if i replaced the caps in the dynacos i dont think they would be good lp speakers with my amp because of the efficiancy in the highs.

A25s have nice warm great mids resolute highs and powerfull sound on digital when dueled in big room. Great bass when dueled in big room, no need for a sub, i own one but not a big fan of subs , my sub is cheap and slow i guess.

I guess its kinda amazing how the room itself can change the sound.

i only wish i could still afford that place haha , It ended up being sold, this place is much smaller, dueled dynacos would never work in here.

One pair sounds better here then one pair at the old place is my guess, But i havent hooked them up yet, i have the bws up.

Vern if you ever get a chance, Duel dynacos in a big room with a mid power tube like solid state amp and woo hooo mids and resolute highs, thats why its like cheating you feel like youre getting more range then you are.

If you want to know more about my observations with this kinda set up let me know because, i was quite suprized when i did it , dueling speakers isent something i would normally do at all, i even thought before doing it," this is stupid but im going to try it " in a big enough room it can work,May be technically incorrect the sales people wouldent want too many people to hear it

[Guest daveshel]

Hey guys. I somehow missed the debut of this section, but I sure am glad to see it.

I am a Dynaco nut: I built my first when I was 14, an SCA-80. When Dynaco first went out of business, I built a PAT5 Bi-fet and a Black box 410 from Stereo Cost Cutters. They served me well for years.

In the last few years I have acquired numerous Dynaco units on ebay, and have had Van Alstine rebuilds done on an ST-120, a PAT5 and recently an ST70.

[dynaco_dan]

>Hey guys. I somehow missed the debut of this section, but I

>sure am glad to see it.

>

>I am a Dynaco nut: I built my first when I was 14, an SCA-80.

>When Dynaco first went out of business, I built a PAT5 Bi-fet

>and a Black box 410 from Stereo Cost Cutters. They served me

>well for years.

>

>In the last few years I have acquired numerous Dynaco units on

>ebay, and have had Van Alstine rebuilds done on an ST-120, a

>PAT5 and recently an ST70.

Hi Dave;

Welcome aboard this very recent forum.

The Dynaco SCA-80 and Q version were extremely popular for the price, great value.

Dynaco did for audiophiles, what Ford did with cars, made products for the, masses and affordable.

Mark, must have realized there was a need and created this forum, thank you, Mark.

Stereo Cost Cutters, extended the death of some classic Dynaco products.

I have never seen any of their products or prices, I understand they bought all the leftover parts from Dynaco and continued using them until they ran out in the early '90's.

Frank Van Alstine's, avahifi.com, Audio Basic's, back issues, are a real pleasure to read.

I certainly get a good feeling about the quality of work they do there.

I have almost all back issues of, The Audio Amatuer magazine.

There is oodles and oodles of Dynaco and other brand modifications.

I sent an email to, Edward T Dell, several weeks ago, the Publisher of The Audio Amatuer Corporation.

I have not received an acknowlegement, or a replay, yet.

I was requesting permission, to freely be able to quote from back issues, at no charge, but with due credit.

I will do again soon.

I am aware of copyright laws, they may or may not be applicable now.

I cannot scan and download to this site until approval is given.

I will not allow any laws to be broken for the sake of a hobby.

There is also, for those interested, oodles and oodles of both tube and solid state Dynaco equipment mods on the internet.

Along with my hifi museum of speakers and electronics, I have some original manuals and copies for some equipment.

I am presently hoarding some of the following, The Audio Amatuer, Glass Audio, a mismatch of past magazine issues, various magazine reviews, various manufacturers literature and Italian Cizek literature.

Paolo, kindly mailed me a copy of the Cizek speakers, from Italy, and I in turn burnt and sent a copy to, Mark, for downloading to the site.

Should anything happen to the original paper documents, there is at least 2 other copies in the world at the present time.

Better brush up on your Italian though. lol

In progress is, Wally's, stack of 100's of assorted literature being scanned and burned to cd's for the site library.

There is some information not valid for this site at this time, but there is always the future and what forums it holds.

I will be burning a copy for, Wally, and for, Mark, for the library, as well.

A friend was recently given a PAS-3X pre-amp, for free, and now uses it, and a Stereo 120 with his AR-3A's.

I am always willing to adopt older classic equipment for my hifi museum.

I do not have a WAF to worry about. lol

I will be adding small mods to this forum as my time permits.

[Guest kfarrand]

Vern, Mark and other afficianados of Dynaco,

Thanks for putting this section up, really appreciate having a forum. Fine with me to discuss Dynaco electronics!

My first Dyna was a SCA-35 kit circa 1968 in college and then added a Stereo 120. Also had A-25s, AR-3as, AR-5s (Cherry), AR-4xs - KLH 17s. I'm now looking for a way to supress the relatively low-level hum in my Stereo 70 with a restoration project. Probably want someone to give me a diagnosis and do the work - any suggestions for a tech who is a real Dynaco devotee - especially if they are within driving distance (Georgia, North Florida, South Carolina).

I may try 'dueling Dynas' and would appreciate any suggestions (Hooked up in series? @4 Ohms).

Kevin.Manson@Gmail.com

2 Pair AR-3as - 2 Pair Dynaco A-25s - Magnepan MMGs -Nakamichi Tri Tracer 700 - Revox A-77 - Dynaco Stereo 70 + 2 PAS 3's - Harman Kardon AVR 520 Receiver - KLH Model Eleven - H. H. Scott LK-72 - G5 iPod - Apple 12" G4 Powerbook - Sony 400 Disk DVD SACD Jukebox

[dynaco_dan]

>Vern, Mark and other afficianados of Dynaco,

>

>Thanks for putting this section up, really appreciate having a

>forum. Fine with me to discuss Dynaco electronics!

>

>My first Dyna was a SCA-35 kit circa 1968 in college and then

>added a Stereo 120. Also had A-25s, AR-3as, AR-5s (Cherry),

>AR-4xs - KLH 17s. I'm now looking for a way to supress the

>relatively low-level hum in my Stereo 70 with a restoration

>project. Probably want someone to give me a diagnosis and do

>the work - any suggestions for a tech who is a real Dynaco

>devotee - especially if they are within driving distance

>(Georgia, North Florida, South Carolina).

>

>I may try 'dueling Dynas' and would appreciate any suggestions

>(Hooked up in series? @4 Ohms).

>

>

>Kevin.Manson@Gmail.com

>2 Pair AR-3as - 2 Pair Dynaco A-25s - Magnepan MMGs -Nakamichi

>Tri Tracer 700 - Revox A-77 - Dynaco Stereo 70 + 2 PAS 3's -

>Harman Kardon AVR 520 Receiver - KLH Model Eleven - H. H.

>Scott LK-72 - G5 iPod - Apple 12" G4 Powerbook - Sony 400

>Disk DVD SACD Jukebox

Hi Kevin;

Before you connect up your A-25's in parallel, check out your power amplifier for it's 4 ohm power rating 20 - 20,000 hz.

See also if the impedance can dip into the less than the 4 ohm zone as well.

If you are listening at lower to moderate levels, perhaps 25 watts minimum per channel at 4 ohms should be sufficient.

I will suggest fusing your individual speakers with a 1 amp fast blow fuse.

Other advice to follow, including low hum issues and others.

Good luck.

[Guest kfarrand]

Thanks for the post. I just added a nice McIntosh MC 2505 Amp (50 WPC) to my system. It should handle the 4 ohm loads w/o any problems given its conservative design with the autoformers. I'm waiting for my Dynaco Stereo 416 to arrive (200 WPC with 16 output transistors + protection circuitry) It should have no problems with this load :-) Always glad to hear from other forum members re their suggestions and experiences.

Kevin.Manson@Gmail.com

2 Pair AR-3as - 2 Pair Dynaco A-25s - Nakamichi Tri Tracer 700 - Revox A-77 - Dynaco Stereo 70 + 2 PAS 3's - Harman Kardon AVR 520 Receiver - KLH Model Eleven - H. H. Scott LK-72 - Sony DVP CX985 V DVD/SACD 400 Disk Jukebox - G5 iP

[Guest vintfan]

Hi Dan et al,

I just got myself two magnificent pairs of A-25's from the same person at a great price. The first pair is SEAS AlNiCo with drivers and cabinet in superb original shape but grills have been redone. They sound really good and musical. The second pair is the first version ScanSpeak drivers but with a twist; the variovent is at the bottom! Cabinet and grills are in great shape but drivers less so. They're sound is less involving and musical but still good. I'll post pics later on another thread...

My question is: Now that I have more than one pair, I'd like to hook them up in a dual/quad two channel setup. My amp is an integrated Yamaha CA-1010 operating at 90W p/c. How do you hook'em up?

Rgds

[dynaco_dan]

>Hi Dan et al,

>

...

>

>My question is: Now that I have more than one pair, I'd like

>to hook them up in a dual/quad two channel setup. My amp is

>an integrated Yamaha CA-1010 operating at 90W p/c. How do you

>hook'em up?

>

>Rgds

Hi there;

What exactly do you mean by a, "dual/quad two channel setup"?

Do you mean two pairs connected to a stereo amp, such as stacking?

The lower cabinet is woofer down and the upper cabinet has the woofer above the tweeter.

This way the tweeters are closest together.

The lower tweeter should be about ear height when you are sitting in a listening position.

If so, connect a pair of leads from one speaker to the one above it, instead of running all the way from the amp with 4 wires.

Red to red and black to black.

This will put them in parallel and the amp now sees about 4 ohms per side.

Be sure to fuse them.

[Guest vintfan]

Hello Vern,

Yep, that's it, two on each side stacked and hooked to the same amp. Will try this and report back. What about fusing them, how? Is it necessary? Thanks.

Cheers!

[dynaco_dan]

Hi Sylvain;

Fusing speakers is like wearing a seatbelt in a car.

Eventually you are going to need them.

Blown speakers is always an un-intended accident, never intended.

Dynaco recommended 1 amp fast blow fuses for their A-25 speakers.

They are pretty cheap and you should always keeps some spares on hand.

You would solder or screw inline, a fuseblock, either at the rear of the amp or speakers, whichever is more convenient to get at when needed.

James, did an excellent job of installing his, check out his photos as an examlple of a solid and careful installation.

Due to the possibility of stepping on, pinching or shorting wires under carpeting, etc, installing them at the amp may be safer.