The Vintage Altec Codex

[junker]

Definitely keeps posted on the tube amp kits. I've looked at doing to Steromour II w/ all the options or Kaiju before. I forget one which ones but you can wire up for 16 ohms too...

[grantray]

The Stereomour transformers can be wired for 16ohms. The goal is to get comfortable enough to build one of Isamu Asano's amps with Western Electric tubes, and then the N-800F crossovers from scratch for the 846As.

At some point, I'd love to hear a good 604 field coils, too, just to get the curiosity out of my system. Since you have a pair of 604 cabinets and the Flamenco's, can you talk about the differences you're hearing between the two setups?

Originally Posted by junker

Definitely keeps posted on the tube amp kits. I've looked at doing to Steromour II w/ all the options or Kaiju before. I forget one which ones but you can wire up for 16 ohms too...

[junker]

Originally Posted by grantray

At some point, I'd love to hear a good 604 field coils, too, just to get the curiosity out of my system. Since you have a pair of 604 cabinets and the Flamenco's, can you talk about the differences you're hearing between the two setups?

Unfortunately, I can't say too much about a direct comparison. I used my Flamenco's exclusively in Orange County, and briefly on the floor at my new place in the Bay Area. Always very enjoyable and well-rounded. The smaller 5-6 cubic foot cabinet volume will ultimately preclude bass extension much below 60 Hz. Replacing the crossover IMO is a hard requirement unless you are primarily interested in keeping them stock. Same circuit just done right. You would be appalled if you looked at the crossover that is potted in the sealed can. I would be doing this as soon as possible. On the floor they had tremendous bass in the new unit.

The 604's main difference is they are quite a bit more efficient. I now run my digital source at -12 dBFS...and the volume on the 15w Shindo Apetite is near the bottom. My 604D have the 604C rolled paper surround, not the pleated-type found on the Flamenco and later 604e. In a big cabinet the bass is all I need from this type of system. Keep in mind that the 604 has the big Alnico magnets found in the 515 LF and 802 HF driver - bigger than the magnets in the Flamenco / Valencia drivers so their efficiency is coming from this. Probably better for very low power designs. The crossover for the 604 should be a series type - either the stock N-1500 2nd HF / 1st order LF w/ or w/o the HF Markwart EQ, or a 1st/1st for lower power application. This is what I'm doing... I'm not sure I see the need for field coil electromagnets. I want to say they seem about 6 dB more efficient than the Flamencos. And probably a better idea for close listening within about 3-4m.

[junker]

Here are a few pics of the insulation that I was trying out. I like the way the inside is done... just leaving the felt in place... maybe good for damping. I kind of want to glue it but not sure I am that committed. Same with the back but I just did a roll up the center. I think it is fine without being over insulated and have coverage all the way down the back. The outsides are pretty good but at the right angles you can see a little hide glue residue that can reflect light a little bit differently. Eventually I might get a small sanders and clean up the edges slightly and the glue residue. Last real open item is to black stain the port edge and cover in black grill cloth from the inside, but first I have to decide if I want to run the Duelund wire through the port or drill another small hole for it...

Room

Inside

Back

[grantray]

Originally Posted by junker

The smaller 5-6 cubic foot cabinet volume will ultimately preclude bass extension much below 60 Hz. Replacing the crossover IMO is a hard requirement unless you are primarily interested in keeping them stock. Same circuit just done right.

Speakers are officially mounted on the stands and placed. The detail retrieval, dynamics, and vibrancy I'm getting now is simply mind boggling. I just found what looks to be a promising DIY series on YT for making crossovers, which is definitely high priority, but i'm sitting here listening to records on the Garrard, and I think a light bulb went on over the head about the 864A cabinet design.

I'm ordering a copy of the Badmaieff's How To Build Speaker Cabinets right now, and I recall you saying the volume for the 864A LF driver is too small. Junker, is there any chance you sourced that info from the Lansing Heritage site's published pages of Speaker Enclosure Their Design and Use? I'll be crawling through that shortly. Which reminds me, does anyone know if there are any programs out there to help with testing designs?

Needless to say, DIY amps may be taking a back seat to speaker cabinet building for the Altecs

[junker]

I can help provide some information to help you get started on the crossover, if you are interested in that. And yes you can get early and late 60's loudspeaker guides. Both are full of great info...

I think there are some programs for the PC, but there are some low tech ways too using a AAA battery for testing phase, and you could use a frequency generator phone app, and an SPL meter. I'm sure it can be done, and be fun if you have the time to iterate. That book shows a way to port tune using a frequency generator (app), o-scope, and a resistor.

I optimized my Flamenco x-overs over a 2 or 3 year period. Mostly layout, upgrading certain components... yes they can sounds very very different, and HF level using various R values and types. I think there was an app that could generate noise and do a Fourier transformation... as an in-app purchase. Crazy... haha

The biggest reason to optimize later on was those padding resistors for the horn... I would strongly recommend getting real 16 ohm L-Pads from Parts Express for level setting... and you could also buy Mast Mutters auto former al la carte to do this instead but they cost $200-300. L-Pad would be a good first pass.

But first some coffee and packing for Japan on Tu.

Check out the blue Hakko soldering station kit on Amazon. Consider an extra tip to cover different applications. A solder sucker to help remove solder. And some solder... I had a small roll of Cardas from Parts Connexion, but some good old school leaded Kester would be great too.

[junker]

Yah you could make a lower speaker extension instead of table if you brace and adjust the porting. I've never seen anyone try it.

Originally Posted by grantray

Speakers are officially mounted on the stands and placed. The detail retrieval, dynamics, and vibrancy I'm getting now is simply mind boggling. I just found what looks to be a promising DIY series on YT for making crossovers, which is definitely high priority, but i'm sitting hearing listening to records on the Garrard, and I think a light bulb went on over the head about the 864A cabinet design.

I'm ordering a copy of the Badmaieff's How To Build Speaker Cabinets right now, and I recall you saying the volume for the 864A LF driver is too small. Junker, is there any chance you sourced that info from the Lansing Heritage site's published pages of Speaker Enclosure Their Design and Use? I'll be crawling through that shortly. Which reminds me, does anyone know if there are any programs out there to help with testing designs?

Needless to say, DIY amps may be taking a back seat to speaker cabinet building for the Altecs

[grantray]

Originally Posted by junker

Yah you could make a lower speaker extension instead of table if you brace and adjust the porting. I've never seen anyone try it.

That's darn close to what I'm thinking Although I want to move the horn outside and mount it on top of the cabinet. (It's too beautiful to stuff in box.) The idea for the cabinet is to make it taller, with a wider baffle and narrower depth. Kind of like Maxonic's painfully gorgeous cabinets, I'd be mounting the woofer near the top of cabinet, although making sure to keep the spacial relationship between 416-Z and the horn.

Here's how the 846A looks up on the finished stand.

[grantray]

Originally Posted by junker

I can help provide some information to help you get started on the crossover, if you are interested in that.

Heck yes! Well, when you get back from Japan, that is. In the mean time, I'll be watching DIY youtube vids, and sketching out the crossover to see if I can make sense translating the schematic to actual parts wired together.

[junker]

Okay sounds good...

Main parts you'll need:

• 2 x 4 uf capacitor - if using modern cap use 3.9 otherwise you can find 4 in Russian NOS
• 2 x 10.5uf capacitor - Russian NOS can find in 10...if you get a few extra can match high. They are cheap enough.
• 2 x 16 ohm L-Pad - Parts Express
• 4 x 3.5 mH inductors - The LF one should have lowest DCR for LF. The HF one can be higher DCR (cheaper) to match stock unit. Air-core is best.
• 16 gauge wire is fine. The Duelund cotton tinned-copper is really nice for about $10/m. Don't forget wire from x-over to drivers. The Duelund and Belden 9497 are good choices.

Originally Posted by grantray

Heck yes! Well, when you get back from Japan, that is. In the mean time, I'll be watching DIY youtube vids, and sketching out the crossover to see if I can make sense translating the schematic to actual parts wired together.