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Paul Spencer

DIY audio: what are you building?

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Hey upfront going the TD mids down to around 50ish, haven’t landed the exact f3 but somewhere around that In ported setup and crossing over to subs for the low end.

It’s going to be fully active setup, still working out the cross to tweeter but somewhere between 1100 and 1300 looks good from initial modelling without sacrificing to much SPL.
Looking forward to this one!

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4 hours ago, hyper said:


Hey upfront going the TD mids down to around 50ish, haven’t landed the exact f3 but somewhere around that In ported setup and crossing over to subs for the low end.

IMVHO if you have subs, then put the TD10(M?) in a sealed box.

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IMVHO if you have subs, then put the TD10(M?) in a sealed box.


Hey Dave,

Definitely makes sense and I did consider that (and still might change my mind) however I did want the flexibility to use them in their own right without support of sub, if I wanted to use them with my recording rig as monitors .. but take your point!

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I've just never had any fun getting a ported box right, that's all  [emoji6]


Ha it certainly ain’t as forgiving [emoji4]

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The enclosure mates have arrived. Pics don’t do them justice amazingly well built drivers can’t wait to get some initial measurements done..

 

 

IMG_9370.JPGIMG_9371.JPG

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From everything I have read...a great speaker...

Now if only the hook up wire connector was copper...sigh...

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Putting together a two stage tube preamp for another SNA member to drive his Holton power amp. I've used a turrent brd. and employed my birds nest wiring techniques. Makes for short a signal path but a nightmare to fault trace. The second stage is a cathode follower which will drive into 10K easy.  

 

The front end can accept any 12A?? tube but the back end should stay 12AU7 for drive capabilities. I've selected  JJ 12AX7 up front for preamplification and a Psvane 12AU7 top of the range "T" series MKII gold pin for the driver tube. What I like about both tubes is tiny plates. Tiny plates = low microphonics. 

 

The inter-stage cap and output cap are Russian military PIO. These have always given a clean and balanced performance and aren't expensive. Resistors are metal film. All silver soldered.  Sockets are ceramic with gold plated pins. 

 

 

image.jpeg

image.jpeg

Edited by mwhouston

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Thanks for sharing this.

Fantastic this preamp is coming together, it sounds like it’s going to be (and sound like) a work of art. 

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The enclosure mates have arrived. Pics don’t do them justice amazingly well built drivers can’t wait to get some initial measurements done..
 
 
IMG_9370.thumb.JPG.877eff86bf1f29e4a6160bd292a193cc.JPGIMG_9371.thumb.JPG.27a94cf23079c74404b9296eca1a7059.JPG
Will be interesting to see what you do with them mate.

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Guest Muon N'
1 hour ago, mwhouston said:

Putting together a two stage tube preamp for another SNA member to drive his Holton power amp. I've used a turrent brd. and employed my birds nest wiring techniques. Makes for short a signal path but a nightmare to fault trace. The second stage is a cathode follower which will drive into 10K easy.  

 

The front end can accept any 12A?? tube but the back end should stay 12AU7 for drive capabilities. I've selected  JJ 12AX7 up front for preamplification and a Psvane 12AU7 top of the range "T" series MKII gold pin for the driver tube. What I like about both tubes is tiny plates. Tiny plates = low microphonics. 

 

The inter-stage cap and output cap are Russian military PIO. These have always given a clean and balanced performance and aren't expensive. Resistors are metal film. All silver soldered.  Sockets are ceramic with gold plated pins. 

 

 

image.jpeg

image.jpeg

I can't see fault tracing being at all difficult there, nice work :thumb:

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5 hours ago, Muon N' said:

I can't see fault tracing being at all difficult there, nice work :thumb:

I agree this one is better opened up than some others I've done. Generally point to point is all parts on a tag board and wire for the brd. I try to solder parts directly to the tube sockets. In some tube power amps this results in a real birds nest. With the turrent brds you can open it up a little more.

 

I have a pair of two stage preamp modules I put together with no hookup wire at all. What I call component-2-component wiring. I'll put up an image. 

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This is not what I was thinking of to post but when it comes to short signal path a Pass BoZ built on itself is about a short a signal path as you can get. The build does include part of the PS. 

 

I was working a lot with early Linux at this stage both at work and at home. Linux was bragging how it was recursive, using and re-using code within itself. I thought why not build a preamp on itself. So here it is The two big brown polies are 10uf output caps. The low ESR caps on the back ensure a good steady voltage right at the amp. The jFets are super glued on the output caps. The heavy wire at the low ESR caps is 99.9% 0.7mm pure silver. 

 

A Melbourne Audio Club member heard the resulting preamp and bought it to drive one of my KT88 SE UL amps. 

 

http://mongreldogaudio.blogspot.com/2010/12/boz-on-cap-bozoac.html

 

Edited by mwhouston

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Hey Mark, where do you get the PIO caps?

 

Cheers,

 

Alberto

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1 hour ago, betocool said:

Hey Mark, where do you get the PIO caps?

 

Cheers,

 

Alberto

Generally just ebay. They usually are not expensive. I've always bought boxes of them at a time figuring it will save on postage. I actually have way too many so if you are just after a few lets know the values and I could post them too you. Some are vey big as you can see others small. Depends on capacity and voltage rating.

 

I used 4uf large PIOs in my Beyma speakers Xover (1st order) for the tweeter section. Xover frequ. was 1100hz. I heard an instant jump in clarity. Also I used low voltage 4uf in one of my Mimic phono stages as the output caps. Extremely good sounding. 

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The start of a pair of carbon fibre/paper machè composite horns.... 90b55818cd5d85167d9f36200f1b6537.jpg&key=c7eaddf98651e79d1c491d7549cd2b337724c1f10292eb705646b32f07e6e8be

 

aafa732fef561861178d4d934e8a3f69.jpg&key=7632a941cf2791f6b4286d12f3ed1e19fa05ee01344965b08f7e660c8420bb77

 

 

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26 minutes ago, Upfront said:

The start of a pair of carbon fibre/paper machè composite horns.... 90b55818cd5d85167d9f36200f1b6537.jpg&key=c7eaddf98651e79d1c491d7549cd2b337724c1f10292eb705646b32f07e6e8be

 

aafa732fef561861178d4d934e8a3f69.jpg&key=7632a941cf2791f6b4286d12f3ed1e19fa05ee01344965b08f7e660c8420bb77

 

 

Someone knows what they are doing. 

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Someone knows what they are doing. 
Haha! I will soon.

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The start of a pair of carbon fibre/paper machè composite horns.... 90b55818cd5d85167d9f36200f1b6537.jpg&key=c7eaddf98651e79d1c491d7549cd2b337724c1f10292eb705646b32f07e6e8be
 
aafa732fef561861178d4d934e8a3f69.jpg&key=7632a941cf2791f6b4286d12f3ed1e19fa05ee01344965b08f7e660c8420bb77
 
 


Impressive mate, did you make the molds?

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Will be interesting to see what you do with them mate.

 

I’m up to my least favourite bit designing enclosures, dam I hate cad programs. I’ve started on the subs which will test my patience a little less [emoji4] once I get the enclosure design done things will hopefully move abit quicker!!

 

IMG_9400.thumb.JPG.0b854f4ea4c78e809f36ad56b8b706a4.JPG

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Impressive mate, did you make the molds?
Yep. Molded directly from one of Martins 550hz Azurahorns. It's been a long running event. I have a purely paper horn with a pair of Radian 950 drivers running with a pair of peerless 8" Nomex cone drivers and thinking of using something larger. Hence the interest in your project.

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Yep. Molded directly from one of Martins 550hz Azurahorns. It's been a long running event. I have a purely paper horn with a pair of Radian 950 drivers running with a pair of peerless 8" Nomex cone drivers and thinking of using something larger. Hence the interest in your project.


Nice work!! azurahorns, that’s the guy over in Perth right? What do you think of the radian comp drivers? Never tried em, always wanted to

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Nice work!! azurahorns, that’s the guy over in Perth right? What do you think of the radian comp drivers? Never tried em, always wanted to
Thanks mate. Yes Martin in Perth. Very nice guy. Very clever. Very nice horns too!
Love the Radians. Lots of detail. Couldn't be happier. So much so, I have a couple more horns in the works for them.

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