DIY talk

I ended up buying this headphone protector PWB
Its also sold by xrk971, but its designed for headphones. SSR is a lower voltage device, I thought the speaker module was overkill for my application.

Its a PWB, so I need to buy the parts and assemble, but will save some money. It doesn't look too bad to assemble, but there are some little SM parts to deal with.

Seems like a nice little board for smallish diy amps, if they don't have built in protection circuits.

I also decided to use an "ideal bridge"
Already have the PWBs, but need to buy the parts. Uses Mosfets and a special controller chip instead of a diode bridge to rectify I'm going to use a mosfet with rdson of 5 milliohms, so much less heat and voltage drop then a diode. The Schottky diodes I was looking at would be equivalent to 100 milliohms.

Randy

 

@dBel84
Hi
Saw in the How to Pass a little time thread that you have a mini aleph
I strongly considering building one, in addition to the sissysit. I bought most of the materials for it long ago, but never finished it. Pretty sure I can now build finish it now with maybe $50 in caps. It would be ugly since I don't have a real case for it, but hopefully would work.

Worth finishing?

Randy

 

yes, I use it daily in my office and it is like old faithful - just gets things right and always a pleasure to listen to.

 

Great, thanks. The board I started is the surface mount one that Brian designed, I don't think there are many of them out there. I also have a set of through hole. Planning to go ahead and finish the SM. SM only supports one pair of output devices, but I think it will be fine, at least I hope so.

Randy

 

I have not seen an SMD version - I built mine with a single output pair

 

I think only a few were sold, and then Brian vanished. I just posted some plots I found on my PC at diyaudio
Layouts and traces for the TH and SM boards that Brian used to sell.
This was from 2006, so only 16 years ago.

I just looked at the datasheet for the 240, I don't see any problem running an amp or two through one device. Three pairs for a mini seems like serious overkill.

Randy

 

I have the through hole PCBs for the Aleph mini and I also had no idea that there was ever and SMD version. It must have been a small group buy.

 

I'm considering cloning a speaker, problem is I don't have the crossover details or enough knowledge to design my own. I do have the picture below and the following details:

• Two way speaker
• Tweeter is a RAAL 140-15D, http://www.raalribbon.com/products_flatfoil_140-15.htm
• Mid woofer is a Scanspeak Revelator 18W/8531G, https://www.madisoundspeakerstore.c...ak-revelator-18w/8531g-00-7-mid-woofer-8-ohm/
• Crossover uses Goertz copper foil inductors, Mundorf resistors and a combination of ClarityCap PX and ESA capacitors

Given all that can anyone identify this design or point me to a relevant schematic?

 

3 coils and 3 caps. Without knowing how they're all connected, it's hard to say. Either 18db (3rd order) networks or 12db (2nd order) with a zobel. Or baffle step compensation...too many possibilities.

Do you own/have access to this speaker? Can you trace how the different components connect to each other? The caps and resistors should have their values printed on them but the coils probably don't and would need to be measured.

Is this a DIY speaker?

 

No access to the speaker. Yes, DIY. Designer had quite a bit of experience though so he might have gone his own way.

 

No access to the designer to ask him? Is there a blog somewhere or some resource or pictures about this speaker?

 

Are they MTM speakers?

https://solen.ca/wp-content/uploads/ananyakit_new.pdf

 

Close but no. I'd already come upon that design, prob through the same DIY thread. This design is single tweeter, single mid.

This was an almost successful attempt at going from DIY to Pro so no tech details were published. A few units were made and sounded fantastic but they didn't sell at the very premium asking price. The designer still has some hopes so isn't releasing info but he's not taking orders either.

I thought I'd take a whack at building a pair for myself but having to trial and error the crossover is a deal breaker, too many other good designs are available. And its not like I'm not already overloaded with projects.

 

Ah this makes sense. This is why he's only posted limited pics that don't give away anything relevant.

 

I just found out about this now but Rick Craig of Selah Audio died some time last year

https://www.diyaudio.com/community/threads/rip-rick-craig-of-selah-audio.376162/

I never got to listen to his designs but they had a very high reputation

 

Oh wow, that's incredibly sad. I just checked and his webpage is expired now too. It seems no one has access to update the facebook page either.

 

The last I looked there was some interest on AudioCircle (i think?) to create site dedicated to his prior designs. I had the pleasure of working with him on one occasion and he was wonderful to work with. RIP, indeed. There are a large number of speakers out there that weren't sold by Craig, but have his finger prints all over them.

 

Anyone here do any distortion measurements?

I just saw this post by Mr Pass at Diyaudio
H2 vs H3
Not sure it this is just for THF-51S's, or if it applies to any of his designs?

Since I'm using these amps for a HE6 at 50 ohms impedance, and maybe at different currents, maybe the H2 vs H3 ratio is different too?

So I might spend part of the weekend playing with REW.
Long diyaudio thread on the subject
I think I have a suitable external sound card to make measurements with, and hopefully the rest of the parts in my junk drawer to build a simple circuit to load an amp and also to lower the amp's output to feed into the sound card.

Or I might do nothing. Throwing it out there in case it was interesting to anyone.

Randy

 

When he says "These are the blessings and curses that come with Triode-like character" my understanding is he's talking about working with SITs (& maybe Triodes) specifically. I could be wrong though.

 

That's what I was thinking too.

Well a SissySit with the THF-51S is in my plans, so would want to be able to make these measurements for it.
And I expect once I put a fixture together and figure out how to do it, will be fairly easy to repeat.

Randy