Pete B
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Posts posted by Pete B
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Hi Robert,
Those look very nice, I've never seen the rubber edged version in real life and I wonder if there is
any difference in the sound. And thank you for the nice comments.
Pete B.
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I've been listening to them all afternoon today and I never owned a pair, never saw an input impedance plot,
my guess was that they'd have an Fc of 60-70 Hz - what a surprise with the Fc at 49 ish Hz. They really have
nice bass depth and impact, not as good as Large Advents but very close. They sound very smooth and
balanced with the L-pad straight up (about 3 ohms in series with the tweeter). Nice detail provided by the
extended response of the tweeter. I'm really enjoying these.
They are placed high in the room, on top of LAs that are also on low stands and they sound like they could
use a dB or two of baffle step but this might also be fixed by placing them on a low stand closer to the wall.
My younger son commented that they sound a bit, just slightly flat (as in depth), and this indicates not enough
baffle step. Overall he liked them very much.
I've said before that these are one of the best sounding American made vintage speakers period I wish that
they did not need a sub and the Genesis 2 is the answer to that issue providing response into the low 28-30s.
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It is interesting that these are rated as 4 ohm DC and 8 ohms nominal which is stretching
the truth a bit. They certainly are 4 ohms DC and then dip to below 5 ohms in the bass and
about 6 ohms in the mid treble.
The woofer Thiele and Small parameters are now posted in the woofer repair thread and it is
clear that these are true acoustic suspension woofers. I was very curious to measure the woofers
in the closed box system. Here are the results:
Rdc = 3.95 3.94 ohms
Fc = 48.4 49.5 Hz
Qtc = .90 .96
I was surprised to find a low Fc of just below 50 Hz and with Qtc being .9 ish they should be
down about 1 dB at 50 Hz, nearly flat. I'd guess that the 45 Hz rating is -3dB.
Here is the input impedance for system PLB-1:
And Zin for system PLB-2:
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I'm keeping these in my collection.
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T&S measurements, posting a picture because the forum strips spaces and makes it difficult to format a table:
Note the very low Fs and large Vas indicating that the filled fillet foam has very high compliance as it should:
Parameters pass a sanity check and pair matching is good:
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I solder directly to the threads of the binding posts in order to provide a gas tight connection to the posts.
The woofer (black) and tweeter (yellow) grounds are soldered to the negative post, an extra black wire is
also soldered to go to the ground terminal of the L-pad. A 10 uF 1% Dayton poly cap connects from the
positive post to the input of the L-pad, the woofer positive (red) also goes to the positive input post. The
cap is glued down with E6000. Tweeter positive (red) is wired to the center terminal of the L-pad. The
picture is blurry and while the solder joints look cold they are actually well done. All connection are hook
type for mechanical strength, then soldered:
Used the stock wire, but soldered the wires to the slip on terminals. Clean the brass first with a nail file or
sand paper. This shows bare wire past the crimp bent back over and soldered:
Other times there is some bare wire right below the crimp where it can be soldered:
I might use these for testing drivers but, obviously, one could snip off the slip on connectors and solder directly to
the drivers. Give the slip on's a shot of DeOxit for long term stability.
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This is what the stock, cheap binding posts look like:
I gripped the plastic push terminals with pliers and twisted about half a turn back and forth about 10 times,
then just twisted hard until they broke off. You can't be sure if this will work so don't do it unless you are
okay with replacing the entire terminal. There are 3 slots that held in the old posts and the outermost
ones are at exactly .75" spacing which is correct for dual binding posts. I drilled them out for a tight fit
to the Big Post (from Madisound) hex binding posts:
The terminal board is very thin at about 1/16" and the masonite is only 1/8" so I decided to back it
up with a 4X5" piece of 1/4" MDF. The crossover board was not glued in with much glue so I ran
a bead of carpenters glue over it. Drilled the Lpad hole through both boards and glued the 1/4" backing
MDF to the now cleaned off and blank crossover board. I also filled the empty hole around the back
of the binding posts with epoxy wood filler, had the type that you slice off and knead handy to fill
the two remaining slots and give the new posts a more solid base:
And with the Lpad to clamp the boards together:
Finished close up, knobs are not needed but Radio Shack 274-0403 1/2" blue look nice and are still available on ebay:
Put the knob on so that full up is at 3 o'clock, then up should have the right tonal balance for most people, full off is
never used and 9 to 3 o'clock is the useful range.
Dual binding posts fit perfectly:
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I've always wanted a pair of EPI 100's in real wood veneer and a pair came up locally in nice
outside condition. When I pulled the grills one woofer had the cone popped out about .5" or more.The amp had gone DC and that completely tore the spider to VC former glue joint. I covered
repair of the good woofer and a replacement in this thread:I tested some of the older masonite faced EPI tweeters here and found temperature dependent
behavior: https://audiokarma.org/forums/index.php?threads/epi-inverted-dome-tweeter-issues.824827/
These tweeters tested without problems and I'll add the results to that page when I have a chance.
This is essentially a stock restoration with a lot of attention to detail. These match the below pair pictured on this page
but with foam edge woofers rather than the rubber ones shown. Also note that the early EPI-100 had a level control on
the tweeter, these do not have them but I am adding 50W Lpads (from PE) because I know that they sound better with
some tweeter attenuation. Two schematics are shown here, one with just the standard 10 uF cap and another with the
cap and the 5 ohm rheostat. Note that the drivers are wired in phase:
http://www.humanspeakers.com/e/epi100.htm
Everyone wants pictures so here are a few of the finished speakers:
Front, note the correct filled fillet foam on the woofers:
Back, I didn't bother to clean the old glue residue but I did add a 50W L-pad and upgraded gold binding posts:
Front, the grilles are near perfect but I'd prefer white Irish linen from 123 Stitch, perhaps someday:
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Where are you located?
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I've always wanted a pair of EPI 100's in real wood veneer and a pair came up locally in nice
outside condition. When I pulled the grills one woofer had the cone popped out about .5" or more.
The amp had gone DC and that completely tore the spider to VC former glue joint. Desoldered the
lead in wires from the terminal strip and that allowed me to completely remove the moving parts
from the woofer. Interesting to note that the VC former is paper rather than a thermally conductive
metal. I've been informed that the Genesis version of this woofer has an aluminum former and I'll
be looking for those woofers. More discussion here:
https://audiokarma.org/forums/index.php?threads/epi-100w-foam-popped-woofer.633766/
Obtained another EPI 100 woofer and refoamed it with filled fillet foam, looks good at first:
On further inspection I noticed that very slight pressure on the spider moved it at the glue joint to the
former. This picture shows the normal gap where about 1/16" of VC former paper can be seen:
Next picture shows the gap at about 1/8" with slight pressure from my finger indicating that
the joint needs to be reglued:
Note also, that the Original Advent woofer and many others often require this type of repair if
they are to be used at full output:
I use JB Weld 2 part epoxy for this type of joint for the strength, ability to withstand
high temps, and availability locally. A shish kabob wooden skewer is just the right shape to
apply the glue without it getting on the spider. I apply it in small amounts working it into the
spider and cone at the joint:
Once the epoxy was applied the wide 1/8" gap did not want to close up. I had to put the woofer
face up on a table and put a weight on the cone to force it down and close up the gap - left it
overnight to dry. I hated to do this since it caused the spider to sag, but the alternative is to scrap the woofer.
Some might try to rebuild it with a new spider but most replacements are often not compliant enough:
The glue is very slow drying and I had to leave it over night. The spider rest position was lower than normal
after sitting for so long. I use rolled up shopping bags pushed between the frame and cone to push it out
and leave it overnight to restore the correct rest position:
Note how the cone is at the full out position with the bags in place:
Completed job, note how the spider is flat again. The spider should always be checked for flatness in
case any previous handling might have caused spider sag:
I had epoxy glue left over and used it to apply a layer on the magnet over the original glue, not pretty but it should help:
Some like to apply damping material on woofer frames and commonly available U-Seal is cheap and
easy to apply:
I'll measure these some time soon.
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That is great to know, are those also 4 ohm?
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We had a turnout of about 40 people, we almost always have excellent turnouts.
I had a fairly bad coughing cold that day and only dropped off my speakers.
We welcome guests to any meeting and to sample in case you're interested in joining.
The dues are not much, IIRC $35 annually, and you certainly get more than enough
food for the price. The cookout and Holiday party have great cooked meals, all the
others are cold cuts but lunch is always served. More info in case anyone is interested in joining:
http://cas.ctaudio.org/Welcome/frequently-asked-questions
We have one guy from upstate NY who might be willing to carpool.
Tom Fine who is the son of the husband and wife team that produced Mercury Living Presence
recordings is a fairly new member and has been giving excellent presentations on the history
of recording.
We usually have a member presentation or reps from industry give presentations at meetings.
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I'm fairly sure that Carl (RIP) tested them and they the most important parameter Fc
in system was way off. Get OLA or NLA woofers from ebay.
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@jkent would you like to bring your AR-3a s to an audio cook out and show them off?
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They'd like you to bring your 3 's if you are still interested, bring a friend or two
if you'd like. We have excellent turnouts, I expect 30 to 40 people. I'll PM you
if you are interested.
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How far is it for you?
They really want 3a s.
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The Connecticut Audio Society (CAS) is having their annual cookout and the Audio theme is
to listen to about 10 of the most popular vintage speakers. We need a restored pair of AR-3a's
and if anyone has a pair in good restored working order and would like to show them off and
attend please message me - we would all appreciate it very much.
The event is on Saturday June 1 in Westport CT.
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Great info, thanks very much! How about that they are still in business.
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Thanks for the info Tom, do you know any more details about how spiders are made?
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It is always good to hear that a person is getting so much enjoyment from their
system, that is what it is all about.
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I've been wondering lately if this EPI/Genesis woofer replacement would work well
as a replacement for the AR 8" woofer:
http://www.humanspeakers.com/e/parts/001.htm
I also wonder how close they are to the original woofers from EPI.
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Amazing work and pictures by the way!
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Jim on AK posted:
The next event will be at the same location on SATURDAY OCTOBER 19th.
Since historically the Fall event doesn't get as many participants we'll be fine as far as crowding and tableavailability is concerned. As mentioned, we'll be instituting a one table per participant policy.
Frankenfest is an audio fest/swap meet that has been going on for many years originally hosted by Frank (RIP) in Clinton MA.
It is organized by people on AudioKarma but we need more people so I am posting here also.
These are the general rules, $5 fee for main person rest of the family is no charge:
We have once again secured the American Legion Lodge in Sutton, MA for Saturday October 19th, 2019.
We have the room for 12 noon until 5 PM though "organizers" can show up early to help "setup".
The location is just off of route 146 south of the Mass Pike (I90) - so this should be a little bit closer for most of us versus Clinton.
Dudley-Gendron American Legion
156 Boston Rd
Sutton, MA 01590
Here's a link to a map:
https://www.google.com/maps/place/A...24bd01d4435f98!8m2!3d42.1598864!4d-71.7401907
There will be an Audiokarma "Barter Town" thread listing gear that people plan to bring but you have tosubscribe to have access to it. It is usually created a few months before the date.
For sellers:
As we saw last time there are tables available.
We should bring extension cords and power strips.
They have an ATM in the bar (could be dangerous, I know).
EPI 100 Restoration
in EPI
Posted
Found some newer (to me) Playing for Change tunes and made a playlist here that I've been listening to: