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Paul Spencer

DIY audio: what are you building?

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38 minutes ago, RankStranger said:

I’m very pleased for you that, in your world, the difference between $35 and $200 is immaterial.

I agree. My new L/R enclosures will be 1960 x 650 x 450 hwd and braced every 150mm or so, so the difference between $A255/sheet for 13 ply BB and mdf at ~$A35/sheet is significant. I did enough testing before that I know my construction methods are fine. As for humidity affecting it, thin out some resin and brush/spray it on the inside. Problem solved. My kitchen and laundry cabinets are mdf, are in a very humid section of my place (airflow not the best) and they're over 30 years old.

 

13 hours ago, RankStranger said:

matrix.thumb.jpg.e742215be565843cabab2b26fafe65fb.jpg

 

@A9X I think I feel better about this one. 12mm MDF matrix design

 

Thoughts?

Very similar to how I build, but I'd also have side/side bracing in each section parallel to the baffle to complete it 3d wise, if the cabinet depth requires it, My new surrounds are very shallow, so they don't have it as the enclosure for the coax (15"+ 8" coax) braces the upper section quite well already. I'll probably add some smaller corner-ish bits around the 15 section, just to be OCD. And I'll use offcuts, so they're free, less sweat equity.

 

Another tip is, to keep your stuffing away from the rear of the driver, staple/glue some cheap cotton fabric to the braces around where the driver is, after you've added the filling. Fluffy stuff does settle a bit over the years.

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This set of bookshelf speakers is made from old cabinets and spare drivers that I have lying around. The woofers are scanspeak 8545 and should go to 35hz at low volumes in these cabinets while the tweeter is a chinese unit that Kenrick sound has used in a couple of their restorations, this one has blue baffles and is sort of inspired by the JBL 4301

IMG_20191129_212552_HHT.jpg

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13 hours ago, oohms said:

This set of bookshelf speakers is made from old cabinets and spare drivers that I have lying around. The woofers are scanspeak 8545 and should go to 35hz at low volumes in these cabinets while the tweeter is a chinese unit that Kenrick sound has used in a couple of their restorations, this one has blue baffles and is sort of inspired by the JBL 4301

IMG_20191129_212552_HHT.jpg

Simple and nice. I like it. 

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I built a 150W SS amp for a friend who bought two pairs of Holton Precision amp modules ten years ago. So impressed was I with the sound I bought a pair of the 300W amp modules. These remained Idle until a few weeks back. 
 

I finally built the amp which I was extremely impressed with and which sold within a week. But I hade built a huge PS for the amp which wouldn’t fit in the enclosure, I had to make a smaller one to complete the amp. Wanting  to use this big PS I bought more Holton 300W modules ( 

HOLTONPRECISIONAUDIO.COM

The NXV500L is designed as a very high performance, high end audio amplifier in the Recording Studio's, Audiophile Amplifier's, Home Theatre and Sub-Woofer Amplifier'sThe NXV500L R5 has...

) to make another amp. That is now complete and sounding excellent but now I have heat issues because I couldn’t get the heatsinks I wanted. Now I’m turning this amp into a 150W amp and turning the new 300W amp into monoblocks to better control the heat.

 

Im extremely impressed with the sound of these amps and compared to other amps I have heard in other’s system it is yet to be beaten. Even a friends new finished 100W Krell Class A monoblocks didn’t top it’s performance. Bass is astounding. 
 

more to come. 

A32CF0A2-5A2D-455C-BF72-512CAC135149.jpeg

7245A948-7B84-40A4-9F6A-7A257366A3F0.jpeg

0FEC6894-00C4-42F4-B108-0FC62C7C346D.jpeg

Edited by mwhouston

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The PS has a 625VAC Tranni with 80,000uf of 100V caps and sits on a sub-chassis. I now need to make a second to move this amp to monoblocks. 

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31 minutes ago, mwhouston said:

I built a 150W SS amp for a friend who bought two pairs of Holton Precision amp modules ten years ago. So impressed was I with the sound I bought a pair of the 300W amp modules. These remained Idle until a few weeks back. 
 

I finally built the amp which I was extremely impressed with and which sold within a week. But I hade built a huge PS for the amp which wouldn’t fit in the enclosure, I had to make a smaller one to complete the amp. Wanting  to use this big PS I bought more Holton 300W modules ( 

HOLTONPRECISIONAUDIO.COM

The NXV500L is designed as a very high performance, high end audio amplifier in the Recording Studio's, Audiophile Amplifier's, Home Theatre and Sub-Woofer Amplifier'sThe NXV500L R5 has...

) to make another amp. That is now complete and sounding excellent but now I have heat issues because I couldn’t get the heatsinks I wanted. Now I’m turning this amp into a 150W amp and turning the new 300W amp into monoblocks to better control the heat.

 

Im extremely impressed with the sound of these amps and compared to other amps I have heard in other’s system it is yet to be beaten. Even a friends new finished 100W Krell Class A monoblocks didn’t top it’s performance. Bass is astounding. 
 

more to come. 

A32CF0A2-5A2D-455C-BF72-512CAC135149.jpeg

7245A948-7B84-40A4-9F6A-7A257366A3F0.jpeg

0FEC6894-00C4-42F4-B108-0FC62C7C346D.jpeg

Now that is one amp I'd like to hear! 

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Does anyone know of a 30-50 Wpc class AB module or kit that would be good for a basic integrated amplifier in the mold of a rotel ra01 or a Naim Nait or rega brio something of that nature?

 

To make an integrated, do I just choose a power amp and a preamp module and throw them in a case together (I know I don’t)? There are lots of kits and modules for class a and class d and valve power amps and pre amps and super high powered stuff as above but I don’t seem to be able to find a basic integrated amp diy thing as a basis for making an integrated like something that a manufacturer would retail in the $500-1500 range. Am I missing something or is this just not done for some reason?

Edited by RankStranger

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2 hours ago, RankStranger said:

Does anyone know of a 30-50 Wpc class AB module or kit that would be good for a basic integrated amplifier in the mold of a rotel ra01 or a Naim Nait or rega brio something of that nature?

 

To make an integrated, do I just choose a power amp and a preamp module and throw them in a case together (I know I don’t)? There are lots of kits and modules for class a and class d and valve power amps and pre amps and super high powered stuff as above but I don’t seem to be able to find a basic integrated amp diy thing as a basis for making an integrated like something that a manufacturer would retail in the $500-1500 range. Am I missing something or is this just not done for some reason?

If it was me, I'd go for any of the Tripath Class D modules, or if your budget allows, I'd love to try some of the Hypex modules.

 

You need a DC power supply, the class D module, a volume pot, and power switches and connectors. Oh, yes, and case. As simple as it get:. On - volume - off.

 

But, you'd have to do your own input selector switch and/or preamp. @mwhouston, where do you usually get your Tripaths from?

 

I once built a no-name IRF chip class D module into a case as described above, and was very pleased with the results on my main speakers. Nothing to shy away from a Marantz amp.

 

My 2c worth.

 

Cheers,

 

Alberto

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Latest project, Pass Noir headphone amp from DIY Audio.

IMG_0001.thumb.JPG.ed7e03959b52140d9b4e286e986d453e.JPG

 

IMG_0002.thumb.JPG.dd724e3d4916402962a5df0dd9feae73.JPG

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21 minutes ago, betocool said:

If it was me, I'd go for any of the Tripath Class D modules, or if your budget allows, I'd love to try some of the Hypex modules.

 

You need a DC power supply, the class D module, a volume pot, and power switches and connectors. Oh, yes, and case. As simple as it get:. On - volume - off.

 

But, you'd have to do your own input selector switch and/or preamp. @mwhouston, where do you usually get your Tripaths from?

 

I once built a no-name IRF chip class D module into a case as described above, and was very pleased with the results on my main speakers. Nothing to shy away from a Marantz amp.

 

My 2c worth.

 

Cheers,

 

Alberto

Hypex looks lovely but a bit over budget. I’m planning to do an Amp Camp Amp at some point but I was looking for something a bit less... exotic? I’ll have a look into the tripath class d ones. Thanks :) 

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5 hours ago, evil c said:

Now that is one amp I'd like to hear! 

Gorgeous work Mark.

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4 hours ago, Ozcall said:

Gorgeous work Mark.

I do my best under trying conditions. Lol. 

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9 hours ago, evil c said:

Now that is one amp I'd like to hear! 

Come down tomorrow. Have a drink and listening. 
 

PM me.

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5 hours ago, betocool said:

If it was me, I'd go for any of the Tripath Class D modules, or if your budget allows, I'd love to try some of the Hypex modules.

 

You need a DC power supply, the class D module, a volume pot, and power switches and connectors. Oh, yes, and case. As simple as it get:. On - volume - off.

 

But, you'd have to do your own input selector switch and/or preamp. @mwhouston, where do you usually get your Tripaths from?

 

I once built a no-name IRF chip class D module into a case as described above, and was very pleased with the results on my main speakers. Nothing to shy away from a Marantz amp.

 

My 2c worth.

 

Cheers,

 

Alberto

Hifimediy. 

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Here is a link to the advanced power output devices Holton uses in his amps. ECW20N20s - 200V at 16A! Specificity for high-end audio not just power FETs. 
 

WWW.EXICON.INFO

EXICON Mosfets have been designed specifically for high power linear use.

 

Edited by mwhouston

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Though now starting on my fifth Holton amp (Built two 150Wers ten years ago for a friend) here are some pictures of a more recent one built with some earlier 300W modules. A SNA member snapped it up within a week of completion. Sort of miss it had a solid revealing sound. 

B2C616ED-9008-4369-BCD2-32885779B000.jpeg

C14B5FAB-FF60-435C-A4B3-5E2F3A251557.jpeg

7E8E4907-9607-4AAE-A55C-C240D4FEB9E6.jpeg

EABD29F9-9545-4D49-9D63-2D7421B91CC6.jpeg

6B22DB6C-25BE-4265-AF62-CE6C4A4E1456.jpeg

160ACE5B-8A8E-46B3-990F-605869B5AA0C.jpeg

85CD9EF0-ACD5-4B3D-8A8B-86D91E79592D.jpeg

16D60B54-B669-417B-9113-EF2D1232AE1A.jpeg

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Playing around with a relay operated input switch box for my single input pre amp.

Up to 6 inputs, but only going for 4 atm as that was the selector I had in my bits box.

I'll build it with 6 pairs of inputs and maybe get around to buying another selector one day.

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Yet another PS completed for the 150W Holton inspired amp to come. With only 80,000uf of 100V filter cap it is not over the top. I wonder sometimes if you can have too much filter capacitance when measures like ESR and inductance come into play. I also wonder if some of the big amp companies have listened for what is the right balance. Is too much too much or is it open ended. I’m not saying 80,000if of cheap filter caps is the right amount I am limited by space. Even if not space critical I would probably only go to 100,000uf anyhow. 
 

This is a lower differential voltage PS. Do caps working well under their voltage rating work and sound better than those running closer to the peak rating! Has anyone found the optimum balance of filtration size and sound. Also I have gone to X2 snubbers here. A little more rugged. And I WBT silver soldered the who’re PS. Usually I would just you a cheaper solder on the PS and save the WBT for the audio cct. If others have purchased this solder lately you know how expensive it is. I bought a whole roll but I’ve seen it sold by the meter on eBay. Hard to see but the 10A diode bridge is soldered directly to the first cap to ensure faster and better current flow. 

59ED878B-07A9-491A-9474-4962102CC506.jpeg

Edited by mwhouston

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38 minutes ago, mwhouston said:

Yet another PS completed for the 150W Holton inspired amp to come. With only 80,000uf of 100V filter cap it is not over the top. I wonder sometimes if you can have too much filter capacitance when measures like ESR and inductance come into play. I also wonder if some of the big amp companies have listened for what is the right balance. Is too much too much or is it open ended. I’m not saying 80,000if of cheap filter caps is the right amount I am limited by space. Even if not space critical I would probably only go to 100,000uf anyhow. 

I was going to ask how you calculated how much capacitance.  Actual calc, or just experience?

 

39 minutes ago, mwhouston said:

This is a lower differential voltage PS. Do caps working well under their voltage rating work and sound better than those running closer to the peak rating!

I would not imagine so.  If the dielectric doesn't break down, then all else remains equal.

 

40 minutes ago, mwhouston said:

Also I have gone to X2 snubbers here. A little more rugged.

It also occurred to me looking at previous pictures, to ask about cap type.  These caps are in the signal path, unless bypassed by a regulator and further caps, but even so then.  So,  does the same criteria apply as for coupling caps? i.e. polyester vs polyprop vs polystyrene vs etc. etc

45 minutes ago, mwhouston said:

And I WBT silver soldered the who’re PS.  . Usually I would just you a cheaper solder on the PS and save the WBT for the audio cct. If others have purchased this solder lately you know how expensive it is.

I hope it was worth it.  I would have had doubts I must admit :)

 

46 minutes ago, mwhouston said:

Hard to see but the 10A diode bridge is soldered directly to the first cap to ensure faster and better current flow. 

Good idea, unless it runs hot.  Clamping it to the chassis would make it run cooler.

 

 

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42 minutes ago, aussievintage said:

I was going to ask how you calculated how much capacitance.  Actual calc, or just experience?

 

I would not imagine so.  If the dielectric doesn't break down, then all else remains equal.

 

It also occurred to me looking at previous pictures, to ask about cap type.  These caps are in the signal path, unless bypassed by a regulator and further caps, but even so then.  So,  does the same criteria apply as for coupling caps? i.e. polyester vs polyprop vs polystyrene vs etc. etc

I hope it was worth it.  I would have had doubts I must admit :)

 

Good idea, unless it runs hot.  Clamping it to the chassis would make it run cooler.

 

 

Yes there is calculations for ripple current etc. which can be applied to cap size. I think it may be a minimum required calc. than this size and no bigger. Others may be able to provide more info here.

 

rule of thumb for cap voltage is no more than 75% of cap rating. For my 100Vers I’m well under that. In the past I have run caps to their rated voltage. Never had a problem.

 

caps directly in the sig. path I would only use a proper audio cap. Polypropylene is a good start. The X2 are for removing noise from the big filter caps. Even on Mundorf Audio grade caps I use snubbers. Easy to do, cheap and why not. 
 

the bridge in both former builds runs cool to slightly warm. Especially in this amp there should no problems with diode current handling. 

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Mark - I don't know the currents involved, but in amps (& preamps) I always go for big chunky bus wires, eg. 1mm or 1.6mm solid copper.

 

You can model your PSU on PSUD if you want. for ripple & step load behaviour.

Keeping ripple say 80dB (0.0001%) below last stage voltage.

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

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