AR3a restoration.

[SatinMill]

14 CT seems a bit too open a weave. Most AR restorers get the 18 CT Wachelt. You may find you can see some of the shiny bits behind the grille with 14 CT and have to resort to adding a layer of fine black scrim like that done commercially with vintage Advent grilles that had 16 CT linen.

Checking my receipt it was 18 count, apologies my memory slipped!

 

[speakerdoctor]

Youe pics are a bit fuzzy. What tweeter did you install?

 

[SatinMill]

They say "Hi-Vi Research" on them.

I got them from Larry along with my mids, I imagine they're the same as those he's selling on ebay currently.

ACOUSTIC RESEARCH AR-3A TWEETER REPLACEMENT-REAR TERMINAL CONFIGURATION | eBay

I like them, though I've never heard an original 3a tweeter to compare to, only a 2ax

 

[Leakstereo20]

Sorry I've not got around to posting some pictures of them till now, funny how life gets in the way.

Since replacing the drivers I've not done anything except remove some velcro pads the previous owner nailed into the corners, I just got the last of the nails out and you can see the holes in the images below. I'm thinking of filling them up with some dark filler then seeing how they look and assessing how to disguise the blemishes from there.

I didn't receive any original grilles for them, the pads added were for larger grilles that I've discarded. I bought some hardboard today for making new grilles as shown in the third picture but I've yet to find measurements for cutting out the inner section.

I can obviously take an approximation from looking at pictures of the originals but if anyone has measurements or a technical drawing that would be much appreciated.

I ordered (edit) 18 count Wichelt linen which has yet to arrive, I'm hoping I can get the hardboard in shape by the time it does.

Finally, the only other question I have is does anyone know where I could get replacement crossover caps cheaply in the UK? Everywhere I've looked is hella expensive.

Thanks!

http://i.imgur.com/iDktO9e.jpg
http://i.imgur.com/BBgENE3.jpg
http://i.imgur.com/KcVzFh7.jpg

This is a picture taken today of AR3a front cover. Note that the outer dimensions as the height and width includes the thickness of the fabric front. Hobe this can help you.
Check the inner dimension on your AR3a before cutting the fiberboard.
I don't know where to find cheap bipolar capacitors.....but Jensen bipolars are fine substitutes for the original Sprague.

Kim
Ps.You can find some AR3a info on my amateur site

 

[Leakstereo20]

Well, leakstereo, please do share pictures of your cabinets after you have finished applying the Palisander to your cabinets! Would love to see them and thanks for sharing the Rosewood information.

Well....a bit late but here they are...AR3a ready:

A new project... AR10pi......totally damaged cabinets ready for new walnut veneer and update drawing of the AR10pi crossover including transformer connections:

New copy of the amateur site (under construction).....for vintage hi-fi people : https://sites.google.com/site/httpstubeamp/

...more at Picasaweb.....

old link: TUBEAMP closes at the end of 2014.

 

[Leakstereo20]

AR10pi capacitor 2500uF

Anyone who knows where to buy 2 pcs. of 2500uF non-polar (NP) capacitors of good quality?....best with a high voltage range.....

I know Sprague NP Capacitors was used in Acoustic Research speakers, but as far as I know, the AR10pi was the only speaker with a crossover construction, where the entire audible frequency range passes through a 2500uF NP capacitor.

It is quite expensive for someone in Europe to buy units and electronic parts in US because of EU tax and shipping.....any suggestions?

 

[Gudmund]

New DIY site available

Anyone who knows where to buy 2 pcs. of 2500uF non-polar (NP) capacitors of good quality?....best with a high voltage range.....

I know Sprague NP Capacitors was used in Acoustic Research speakers, but as far as I know, the AR10pi was the only speaker with a crossover construction, where the entire audible frequency range passes through a 2500uF NP capacitor.

It is quite expensive for someone in Europe to buy units and electronic parts in US because of EU tax and shipping.....any suggestions?

Unfortunately LS20 has closed the account, but another site is available with repair suggestions to the Acoustic Research AR3a and AR10pi speakers:

https://sites.google.com/site/httpstubeamp/home/ar3a/ar3a-rebuilt

gudmund