Semi doc modded arcam 2s

A place for DIY project discussions.
Ordinaryman
Posts: 475
Joined: Tue Apr 16, 2019 4:50 pm
Has thanked: 100 times
Been thanked: 77 times
Great Britain

Semi doc modded arcam 2s

Unread post by Ordinaryman »

I have had my arcam 2s for many years. Removed the stuffing long time back, stuffed the ports with straws and lined the cabinets with slate tiles. Did buy some steel but it proved to be a pig to cut and get right. Since getting the little ap30 I have been listening to them more and more. Don't get me wrong my cubetts are staying, these just seem to be better than i have ever heard them.
So to the question. I would like to try removing the crossover trouble is I know fek all about electronics and a novice when it comes soldering. Is there someone here who could tell me what resistor etc I will need and be prepared to draw/ explain where and how they fit "think small child" with this :oops:

User avatar
karatestu
Posts: 5945
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Has thanked: 1865 times
Been thanked: 1378 times
Great Britain

Re: Semi doc modded arcam 2s

Unread post by karatestu »

Apparently the xover is an 8 component affair with a second order filter on each driver crossed over at 3 KHz. Probably accessed by removing the terminal panel on the back.

These speakers were highly thought of back in the day. Are you sure you want to mess with them ? If you are hell bent on doing it then you will most likely have to dope the mid bass driver to attenuate the higher frequencies and remove any nasty cone break up modes. There aren't many drivers that can be left to their own devices with no low pass electrical filter.

You will still need a capacitor in series with the tweeter and a padding resistor. 12 ohms was the value of resistor most often used but you may have to tweak that value as it will depend on how much dope you add. 3.3uf was the most often used value of capacitor but i would say it could need tweaking as well either way (2.2uf or 4.7uf).

You don't know until you give it a go. If just the area where the two drivers cross over is too loud then you need to decrease the cap value. If all of the frequencies above the crossover are too loud then you need to increase the resistor value. Your xover frequency will increase from the stock 3 kHz to something around 6 KHz if you use a 3.3uf cap (assuming the mid bass is 8 ohms nominal impedance). This means the mid bass will be beaming more as it is outputting a higher frequency relative to it's diameter. Only you will know if that is a problem or not. With the cube designs the beaming doesn't matter so much as the mid bass is pointing at the ceiling. Getting the xover out of the critical range where the ear is most sensitive is a good thing however.

I don't want to put you off but do you realise what you are getting in to here ? :think:
These users thanked the author karatestu for the post:
Ordinaryman (Wed Nov 25, 2020 6:58 pm)
DIY FREE ZONE

Ordinaryman
Posts: 475
Joined: Tue Apr 16, 2019 4:50 pm
Has thanked: 100 times
Been thanked: 77 times
Great Britain

Re: Semi doc modded arcam 2s

Unread post by Ordinaryman »

Thanks, don't think I realized at all. Removing wadding, filling the ports with straws and lining the cabinets with slate made a BIG difference (easy to do) even before I got my first nva amp. With it they sound even better. Maybe the best thing to do (for me) is just enjoy what I have.

Daniel Quinn
Posts: 8586
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 24 times
Been thanked: 399 times

Re: Semi doc modded arcam 2s

Unread post by Daniel Quinn »

Firstly disconnect the bass driver crossover and play. You should find enough about the driver and sound to know if your going to like it.
These users thanked the author Daniel Quinn for the post:
Ordinaryman (Wed Nov 25, 2020 7:29 pm)

User avatar
Fretless
Posts: 9290
Joined: Wed Nov 12, 2014 12:15 pm
Location: Somewhere in Holland
Has thanked: 1487 times
Been thanked: 2280 times
Netherlands

Re: Semi doc modded arcam 2s

Unread post by Fretless »

I did similar with my Arcam One's; removed the wadding and partially covered the port with Duct Tape (about 2/3). On opening them up, the casework is so solid with heavy-duty internal bracing that I felt steel lining to be superfluous. One thing I did do was remove the connection plates for the bi-wire link to the tweeters and replaced them with 2.5mm solid copper mains wire. Left the crossovers alone but enjoy the lovely smooth sound of these speakers on an almost daily basis.

Upstairs:
Vinyl
Pro-Ject 1.2 + Grado Sig Jr + Cambridge Alva Duo
DigiVolumio PC + Kiss DP-500 + Sabaj A20d
NVA: P50sa - Cube2 - SSP - LS6+ Sabaj A10a (x2)
Downstairs:
Vinyl
Logic DM101 + Syrinx LE1 + Grado Sig MCX
DigiDenafrips Ares II + Volumio PC + Cambridge CXC
NVA: P50 - BMU+ Aiyima A07 MAX (x2) + Arcam One
HP: HifiBerry Digi+ PRO + Sabaj A10d
Office:
Allo DigiOne SIG + SMSL M300se + Douk G4 (x2)
Mission 760 + Monolith THX AAA 887
Headphones: German Maestro & AudioQuest

Ordinaryman
Posts: 475
Joined: Tue Apr 16, 2019 4:50 pm
Has thanked: 100 times
Been thanked: 77 times
Great Britain

Re: Semi doc modded arcam 2s

Unread post by Ordinaryman »

+1 don't like the ports completely blocked, hence straws. Mine are not bi wire? Very lucid underrated speaker imo so much so I just purchased a second set , just in case :grin:

User avatar
Fretless
Posts: 9290
Joined: Wed Nov 12, 2014 12:15 pm
Location: Somewhere in Holland
Has thanked: 1487 times
Been thanked: 2280 times
Netherlands

Re: Semi doc modded arcam 2s

Unread post by Fretless »

The original Arcam One series could be bi-amped.

Image

Upstairs:
Vinyl
Pro-Ject 1.2 + Grado Sig Jr + Cambridge Alva Duo
DigiVolumio PC + Kiss DP-500 + Sabaj A20d
NVA: P50sa - Cube2 - SSP - LS6+ Sabaj A10a (x2)
Downstairs:
Vinyl
Logic DM101 + Syrinx LE1 + Grado Sig MCX
DigiDenafrips Ares II + Volumio PC + Cambridge CXC
NVA: P50 - BMU+ Aiyima A07 MAX (x2) + Arcam One
HP: HifiBerry Digi+ PRO + Sabaj A10d
Office:
Allo DigiOne SIG + SMSL M300se + Douk G4 (x2)
Mission 760 + Monolith THX AAA 887
Headphones: German Maestro & AudioQuest

Post Reply