Vintage Bang and Olufsen Recycle build

[thehillboys]

Yep thought if I did not like the sealed, I could build a box behind the baffle and vent.
Started glueing the cabinets for the recycle project today. Cut crossover boards. Coming along slowly. Working on what to do with the tweeters. I am thinking of making another ring and then sandwich mount them. Still have the other tweeter hole to deal with. Put an eyeball or something in the hole. Not sure yet. I will keep you posted. The cabinets will be solid. Have the crossovers mapped out. They will be put on a horseshoe shaped piece of thin MDF fitting around the port. I am going to try them with the existing port and see how low they will go. They are calculating out at about 38 Hrtz I can go lower reducing the diameter, but that will take modification.

[thehillboys]

Modified cabinets

[thehillboys]

Cabinets with one coat of stain. Modified internal cabinets with two braces and 3/4 MDF lined walls. Makes the walls 1 1/2 inches plywood outers MDF inner walls. Makes them very dead. Starting work on crossovers and baffles next. I am gong to try the mid inclosed and sealed in the cardboard tube that the other mid was enclosed in. The 8" and tweeter will be in the remaining enclosure. Going to use the previous tubes. With the volume and the tube, it calculates it tunes to about 40.

[chrisn]

looks good!

[thehillboys]

Crossovers finished. Working on the baffle now. Should have something to test tomorrow.

[thehillboys]

Thanks, fun project. Should have them finished soon.

[thehillboys]

A couple of new pics. Assembled and testing. I still have to apply tru-oil to the cabinets and get black screws for the baffles. Coming along.

[thehillboys]

The tweeter is in the original mid range hole and the original tweeter hole is a dummy covered with a mdf puck covered in grill cloth and glued to the baffle. I built rings for the baffle for the 7 and 8 inch woofers to attach to. they fit pretty good in the original holes. I used the original hardware to clamp the rings down. They are heavier than the original so they are taxing the stands a bit. I also did not account for the binding posts interfering with the stand so they are leaning a bit back than normal. Fix this at a later date.

[thehillboys]

First listening impressions. I designed them to have a flat response. I can definitely hear them flat. My ears are used to hearing a baffle step and bass bump which I do not hear from these. Not that they are weak in the bass, but not what I am used to hearing from my other speakers, pushed up against the wall and muddy. My topping mx3 is running them now with virtual ease, so they are not hard to power. I did bump the bass up +5db and they sound more like what I am used to. The mid and tweet sound really good. I did use the original port which tunes the box higher than it can go with the woofer. I may experiment with a smaller diameter tube to go lower. Until I get a microphone and can measure, I am just guessing what I am hearing. Enclosing the mid makes me think I may be robbing it of a bit of its lows. Maybe not at the crossover point. In conclusion, they sound good, but are not quite there as far as the bass is concerned. May rework or just equalize the bass or add a sub. Until I measure, I do not know if their is anymore adjustments that need to be made. Thus far, they make good sound.

[thehillboys]

Dialing in the sound a bit. I was getting this lack around the lower crossover point, subjectively that is. I have yet to measure them. I did pack the mid tube quite a bit with the fill that was originally in the tube. Theory was that it was packed too dense with fill. Theory had merit. I tried half the fill and it opened the mid and lower mid up quite a bit. Brightend it per say. Sounds better. They is still not enough bass for my tastes and probably never will be. I am a bass player what can I say. Will look for adding a sub. I am playing them with my sub in my movie room at the moment and want that bass. I may try tuning the port down a bit with a tube inside the tube and see what happens. Do not know if I will ever get low enough for my tastes. It is hard to put numbers to subjective listening, but with the sub, I will give them an 8, without a 6. As good a sound as my older diy Audax system, slightly below the Zaph 5.1 diy I built for my sister. I think with a few tweaks and room improvement when I get them into a treated listening room, they will be my reference speakers until I build better. They are retro sexy by the way. A 9 on the sexy scale. Better looking than the originals with darker wood and the RS drivers.

[thehillboys]

Next step is about 5 coats of gun stock oil on the wood and find an amp to power them. Love recommendations for an integrated or Pre-amp combo sub $1000. I am going to re-cap my 1980s NAD to pair with them eventually. Thinking a DAC might work as a Pre-amp. Thinking about the Icepower or Hypex diy builds might fit the bill with a DAC. Love your thoughts.

[technodanvan]

They look really great already, I imagine five more coats will have them glistening. Are you actually treating these as a four-way?

[Mikerodrig27]

Love recommendations for an integrated or Pre-amp combo sub $1000.

Since you are into DIY, build a Firstwatt F6 clone.

https://diyaudiostore.com/collections/parts-kits-for-first-watt-clone-boards/products/f6-board-transformer-kit

https://www.ebay.com/itm/AS-4218-400VA-18V-x2-18V-0-18V-Audio-Amplifier-Power-Transformer/254682404255?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

https://diyaudiostore.com/collections/deluxe/products/deluxe-4u-amplifier-chassis-steel?variant=21140261444

https://diyaudiostore.com/collections/consumables/products/keratherm-transistor-insulators

https://diyaudiostore.com/collections/power-supplies-accessories/products/universal-psu

https://diyaudiostore.com/collections/jfets/products/linear-systems-matched-jfets

https://www.diyaudio.com/forums/pass-labs/277850-f6-illustrated-build-guide.html

You will have to order parts from Mouser or Digikey for the power supply board but this is a top tier kit designed by a top of the line amp builder Nelson Pass. 25w at 8 ohms and 50w at 4 ohms. You will be surprised how far that will get you. I went with DIYaudio's top of the line chassis and the parts cost ended upbeing $805 for everything.

[chrisn]

Looks good! You mention the mid not having enough lows ( i may be interpreting that wrong) but it looks like you have it high passed?

[thehillboys]

The top tweeter hole is a dummy piece of mdf covered with speaker grill cloth. The crossover is a 3 way so the RS180 is crossed both around 350 and 2000k. It is enclosed in its own tube recycled from the originals. I had it stuffed densely at first and have backed off to about half of the original amount of Poly. The 8" on the bottom could go a bit lower. I have it tuned using the original port tube that was 4" diameter by 10" long. With the volume estimated I think it tuned to about 39db.

[thehillboys]

I was going to enclose the tweeter and mid into their own sealed enclosure, but with the baffle it would have been difficult to get it sealed off. Why I reused the tube for the mid. It also increased the volume for the RS225-8. Crossover diagram is above.

[thehillboys]

That looks super fun and looks like a bunch of work. thanks for the idea.

[thehillboys]

They were originally a four way. The tweeter is in the 4" hole where the upper mid was originally.

[thehillboys]

I am going to recap my NAD first and see if I like working on Amps. Also have some other DIY projects in the works. May pull the trigger on an amp for the time being, leaving a DIY amp for the future.

[Mikerodrig27]

That looks super fun and looks like a bunch of work. thanks for the idea.

https://diyaudiostore.com/collections/b1-buffer-w-korg-triode-pre-amplifier/products/korg-nutube-b1?variant=29449217802274

this would be easier to build.

[thehillboys]

Those kits look like fun, but I think I will not have time for a while. Looking at integrated or a pre-amp/dac stack for around 1k if you have any suggestions.

[thehillboys]

I am stopping at 3 coats of gun stock oil. They are getting a bit shinny and look good at the moment. When they dry, I will put on a coat of wax and call it good. They are sounding better and getting a bit deeper. I think. This opens up the break in debate about woofers and caps. Maybe my ear is starting to hear them more. I still do not have them n my listening room. I did score a Hegel H70 integrated amp that I will give them a go with. I still do not have measuring equipment and want them to break in a bit more. We will see what the amp will do for them. I am running them with an old Demon 7.1 with the TV as my source. Should make a difference.

[thehillboys]

Amp came today and they sound really good. Love the look. Pretty sexy system so far if you ask my biased self. Still wanting more lows. Will try adjusting the port. Sub is probably the answer. I do not like missing my low end. I think 7.1 sub driven movie watching has ruined me as far as bass goes. I do have a sealed sub that I may mate with the system. Not quite so boomy. The speakers seem to be breaking in a bit if that is a thing? Probably more the training of the ears. I am listening to them without a sub at the moment to see just exactly where the bass hits. Without measurements who knows how low they are and where they actually drop off.

[thehillboys]

Fired up the old NAD 3240pe after a quick cleaning. Sounded great. Not as good as the Hegel, but surprisingly good for a 30 year old amp that has been sitting for 15years. Looked great inside and out also. I bought it in late 80s. I did not run it a ton before surround sound silenced it. No leaky or bulging CAPs that I could see. Other than a bit of a crackling volume knob which worked itself out. Looking forward to what it will sound like with a DAC. Not a fair comparison with a digital source from the CD player going into the Hegel day and using the CD player DAC for the NAD analog in. Probably a good candidate for a re-cap.

[Mikerodrig27]

That Hegel looks like a nice unit. I saw a nude pic of it and there is a large toroidal transformer in them. The board and layout looks nice too.

I haven't had the best luck with NAD in the past. What you mentioned reminds me of the units that I have had. Sounded good but not the best that I have heard. Do you have a turntable you can hook up to both units?

I have also noticed that in most cases, a recap would reduce noise but not provide much mileage towards clarity. However, recapping is a fun project.

Glad you are making such great progress on your project(s)! Thanks for keeping us up to date.

[thehillboys]

The Hegel was a good find, virtually new. Sounds amazing. The NAD, I am the original owner, so it has sentimental value. It still sounds pretty good. I am thinking with a clean signal from a DAC might wake it up. The Hegel does sound better and will be the go-to. I will keep an eye out for a class D amp, or build one to compare. I may use the NAD as a preamp phone stage when I get a turn table. I do have use of the B and O turntable that came with the speakers originally in the 80's. Have no idea whether it works or not. May investigate. My record collection is mainly imports and picture discs that are still sealed, so I do not have many records to play. May just get a turntable for a piece of art.

[thehillboys]

I have been investigating burn in and if it is a thing. I am noticing that the smaller speakers I built with the original tweeters are sounding better and a bit deeper. I have also been using them more. they will sound amazing when I add a small sub with them. A very nice side project to give me sound to the bedroom.