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1 minute ago, aussievintage said:

Reminds of the very first radio sets, built back when there were not so many passive components readily available.  Circuits tended to be mostly transformers and DH valves.    

 

Supposedly trannies produce less distortion compared to caps. It you can use an inter-stage tranni instead of a cap in a power amp to connect the driver to the power tube, its meant to be better. Not tried it yet. 

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Stereo Subs & Two Way Monitor Build   It’s been slow going on my two way monitor with stereo sub build but I’ve finally finished finished one of the two subs!!!   The subs are 10inch CSS drive

Finally finished my 6sn7 preamp. 😀 not a bad outcome considering 50% material was recycled. Thanks a lot mwhouston for schematics.

Thanks Pete Sure! Pretty much just used common spray acrylics (cans) for the whole job. Not shy of using 2k but just trying to save on costs.  After the cabs where routed i gave th

2 minutes ago, mwhouston said:

Supposedly trannies produce less distortion compared to caps. It you can use an inter-stage tranni instead of a cap in a power amp to connect the driver to the power tube, its meant to be better. Not tried it yet. 

 

Personally I don't believe that.  Transformers were an evil we fought to not have to use.  Early transistor push-pull amps used them, and we all praised the newer ones that did away with the interstage tranny, then even better when the output transformer wasn't needed.  Benefits  expected  were such as improved linearity and frequency response.

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Pros & cons IME.

ITs have limitations & need to be v well designed & implemented in order to minimise these drawbacks.

OTOH passive components, like caps impart audible 'flavours' too - at least at 'hi-fi' levels of 'discernment.

Don't you think?

 

There's always trade-offs it seems in this game ;)

 

Cheers, Owen

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

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20 minutes ago, aussievintage said:

 

Personally I don't believe that.  Transformers were an evil we fought to not have to use.  Early transistor push-pull amps used them, and we all praised the newer ones that did away with the interstage tranny, then even better when the output transformer wasn't needed.  Benefits  expected  were such as improved linearity and frequency response.

I was referring to inter-stage trannies. Yes trade offs, the Hammond inter-stage only go to 15K. In the power amp above they ring also due to the tank cct. . A 47K resistor across the secondary stops that. 
 

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1 minute ago, mwhouston said:

I was referring to inter-stage trannies. Yes trade offs, the Hammond inter-stage only go to 15K. In the power amp above they ring also due to the tank cct. . A 47K resistor across the secondary stops that. 
 

Yes so was I, as well as outputs.

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I just realised the schematic above has the wrong input Tranni.. The Hammonds have a 400ohm primary and a CTed secondary. My schematic is a redraw of the original where he used microphone trannies. I used the Nickel core Hammonds. 

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On ‎26‎/‎05‎/‎2020 at 1:08 PM, aussievintage said:

Hey, check this out - cheap device (can be had for less than $10)  that measures diodes, transistors, resistance, capacitance, inductance etc etc, and even sorts out the pinouts and displays the results graphically.

 

Google LCR-T4

 

 

 

616EUuSuk2L._AC_SL1010_.jpg

I have had one for a couple of years. Added  some leads to test bits that would not fit.

 

1426313737_DSC06599e.jpg.ecb089b278f7f02de50955a5c01319d0.jpg

Edited by btd
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32 minutes ago, mwhouston said:

Something I stumbled on in FB.

 

Some may find it useful. It may be the opinion of one person in one system.

DA1393FB-3C61-4974-B6D1-38A6E8FEBEE5.jpeg

Oh that’s great. Could use something like this for more tube types

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Well thats VERY annoying, I stuffed up my calculation for the number of turns I needed and when I did the first test I had 244v not 150v!!!!!!!!!!!!!

 

No idea where I went wrong, so I had to remove 220 of the turns that I so carefully put on.

 

The first photo shows the plump and great looking 244v version and the second is the final voltage test, at least that parts done. Oh may aching back :)

Tren  244v.jpg

Tren 150v.jpg

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Arrived today.  Only $10 even from Amazon au.     I love the fact that I get an email that it is arriving today, I check the tracking website on auspost and it tells me it has been delivered, so I go out to the letterbox, and there it is  !!!!

 

 

HiLetgo® LCR-T4 Transistor Tester LCD Display Diode Triode Capacitance ESR Meter Mos PNP NPN SCR Inductance DIY 9V 12864 LCD

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23 hours ago, mwhouston said:

Finished inside just the XLR plug to go on the power cord to feed HT, Vf and grounds to the preamp. 

913FBA81-E4CF-43D7-86E8-E07B4ED38D9F.jpeg

 

I love how you can pick up little tricks.  I like how you use a couple of zip ties to stop the 240v cable pulling back through the grommet.

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Recently I started (and now finished) an Elekit 8340. I went all out with the options:

- Takman resistors

- Mundorf Supreme EVO Silver Gold Capacitors

- Alps potentiometer

- Lundahl output transformers

- EH KT88 and preamps tubes

 

Really fun to build, took me a big part of the week-end and a couple of evenings. And I finally plugged it in Monday evening, and I was very disappointed...! I was sure something was wrong so did all the checks (you have 46 different voltage checks on the PCV), and everything was fine. It was not that bad, but the little brother Elekit 8200 was doing everything better. Everything was blurry, bass were out of control (so boomy!), I felt like I was listening to a kids' end-of-the year show...

 

Then, I spent some time online to read reviews and found this one: https://wallofsound.ca/audioreviews/speakers/elekit-tu-8340vk-follow-up-reviewed-with-lundahl-transformers-and-triangle-speakers/. The reviewer is talking about a pretty long breaking in period for the transformers. And let's be honest, I'm not really into the "break in" periods (then again I was not into cables until I tried Mike Lenehan's foliflex. - Still not into digital cables, different story) but damn I wish I knew how much the sound was going to change so I could have set a couple of really sensitive mics in front of the speakers right then and now to compare. The 8200 sounded very good right "out of the box" (I had the stock transformers though). The sound slowly but surely got better with the 8340. The sound stage image got more precise, the violins don't make my ears bleed anymore, voices are really smooth and "present". Really precise yet relaxed sound. I'm really impressed now and I'd say this is an excellent amp, and brilliant value for the money! The bass are much better too, but still a bit boomy, I'll keep you updated in a week or so.

 

Have you ever experienced changes that big during breaking in period? I'd be keen to hear your thoughts. I might be crazy.

 

 

 

(Tracks used for critical listening sessions, I used tracks I know very well, and tried to keep the playlist short:
- The greatest video game music by London Philharmonic Orchestra: Super Mario Bros Theme

- The greatest video game music by London Philharmonic Orchestra: Tetris Theme (These two tracks are brilliant for bass tightness test)

- The Eagles - Hell freezes over: Hotel California 

-  Bach - Chaconne, Partita No. 2 BWV 1004  by Hilary Hahn

-  Florence and the Machine - MTV Unplugged: Dogs days are over)

 

 

 

 

 

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Edited by JulesOz
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Dang!

 

I ordered an Oatley RIAA Tube Kit the other day (http://oatleyelectronics.com//product_info.php?products_id=936) and as luck would have it, they weren't able to deliver it and refunded me. I believe @mwhouston you built one of them? That's what the Internet says anyway.

 

Now I'm in between should I wait for them to be in stock (should be a few weeks) or do I get Rod Elliot's P06?

 

Cheers,

 

Alberto

 

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1 hour ago, betocool said:

Dang!

 

I ordered an Oatley RIAA Tube Kit the other day (http://oatleyelectronics.com//product_info.php?products_id=936) and as luck would have it, they weren't able to deliver it and refunded me. I believe @mwhouston you built one of them? That's what the Internet says anyway.

 

Now I'm in between should I wait for them to be in stock (should be a few weeks) or do I get Rod Elliot's P06?

 

Cheers,

 

Alberto

 

Never built this one. A few others but not this one. The others got good reviews. 

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On 27/05/2020 at 11:25 AM, Batty said:

I'm looking for tips on how to paint MDF speakers, atm I am sanding them to level all the joints, then I assume I need to prime them before painting, I'm thinking of a satin finish.

But as I have not done much serion painting I was looking for advise on how many coats and how far to sand back between coats, even how long to allow the paint tod dry before sanding back.

 

TIA for any help.

Hey Batty, have ya got a compressor and spray gun?

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1 hour ago, Lazz said:

Hey Batty, have ya got a compressor and spray gun?

No Lazz

 

I will be doing it the worst way with spray cans.

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56 minutes ago, Batty said:

No Lazz

 

I will be doing it the worst way with spray cans.


eesh. Do you have a workshop nearby that you can take it to that does 2 pac? A cabinet maker or panel beater or something like that? There’ll be a cost and it’s not strictly diy but it’s real hard to get a clean finish on mdf and especially with a spray can. Hardest part is the glue joins take the colour differently to the rest. It’d be a shame to end up with a speaker that you love to listen to but hate to look at :) 

 

Maybe you’re awesome with a spray can but I would have real strong reservations about doing it that way

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I'm not a looker, I am listening to them now and they are awesome,

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First puzzle solved in my new Holton build. Purchased the solid state relays but unfortunately the mounting holes and position doesn't work with my terminals or case so have instead decided to mount directly to the amplifier boards instead by soldering a spade (that I had flared out on the pad side) to the amp input on the protection module and using some old  solid core inductor wiring to the negitive side onf the amp. module.

 

20200606_134936.thumb.jpg.ba0507c21723af0602d63c85bbd8211b.jpg

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After building a pin F5 and Holton amp for others I’ve gong to build one of each for myself. I have most of the parts for the F5 and what I dont have has been ordered.

 

Here is the mourning for the rectification and smothering. Yet to soldered to a bus bar underneath. 80,000uf of 40V caps and 10A bridge. F5 brds have been populated. Waiting HS. 

9D9E16AC-40DA-4E8A-AF25-EC3A63E5BF6D.jpeg

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3 hours ago, betocool said:

Isn't this your handiwork?

https://diyaudioprojects.com/Tubes/6418-Tube-Phono-Preamp-Kit/

 

Cheers,

 

Alberto

Yes this one is the first of the phono stage they came up with. It use a SMPS on board. I’m pretty sure the latest one is different or is it a different SMPS. 

 

Also see the second one where I used a linear PS. This preamp got some good reviews from a few. 

Edited by mwhouston
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Doug,   you could use those transistor mounting clips (or actually the bar version from Jaycar, etc) with the hole in the middle - you only need 4 holes per heatsink then for the 8 fets - it's a simpler way to mount the single bridge diodes on heatsinks too.

There's also some specific spring clips from Mouser, RS, etc that apply a more constant pressure on the transistor case/device - these also come in dual clips (can easily cut them apart) but do need 1 hole per transistor for accurate control of spring clip's tension

 

These save worrying about drilling/tapping accurate vertical holes for the retaining screws, which can be a real PIA!

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8 minutes ago, HdB said:

Doug,   you could use those transistor mounting clips (or actually the bar version from Jaycar, etc) with the hole in the middle - you only need 4 holes per heatsink then for the 8 fets - it's a simpler way to mount the single bridge diodes on heatsinks too.

There's also some specific spring clips from Mouser, RS, etc that apply a more constant pressure on the transistor case/device - these also come in dual clips (can easily cut them apart) but do need 1 hole per transistor for accurate control of spring clip's tension

 

These save worrying about drilling/tapping accurate vertical holes for the retaining screws, which can be a real PIA!

 

Yeah been thinking about this very thing as those low pressure clamps and silpad certainly make life a little easier.

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I managed to get the resin done today, but as always seems to happen with expoxey resin it manage to find a way out, hence the yellow tape to stop the leaking. I had a silicone seal where the clear plastic met the sewer pipe cap but it got through anyway. I coated the inside with mould release  but now the resin has got between the clear plastic and the cap it looks like I'll be cutting it out.

20200607_121034.jpg

20200607_130713.jpg

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made some aluminium plates for the binding posts I got from @andyr

 

they need a final finish but I’m pretty happy with how they turned out. My 60L seas FA22 full-ranges are more or less in the finishing stages now so I’m going to hold off posting more pics until they’re done then I’ll give them their own thread. Shouldn’t be more than a few weeks but I’ve never veneered on this scale before so I’m going to prioritise care over speed

 

happy to hear any home-veneering tips anyone has wrt glue, clamping, etc. Surfaces are approx 300 x 600mm and 300 x 500mm so not huge but not tiny either
 

5F87D2D3-9825-499B-BECA-C395CA3CE74C.thumb.jpeg.e7e5b4e2ecca5411106b88bfcdb76935.jpeg509E8FD3-06A3-45FE-9C75-927CAC9ABE2C.thumb.jpeg.7c794b4259231e8f827e291dc51d81ab.jpeg

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42 minutes ago, RankStranger said:

made some aluminium plates for the binding posts I got from @andyr

 

 

509E8FD3-06A3-45FE-9C75-927CAC9ABE2C.thumb.jpeg.7c794b4259231e8f827e291dc51d81ab.jpeg

 

Very cool, Simon!  :thumb:

 

Can you tell me what drill size you used for the main barrels?

 

Also, how did you make the notch in the side of the hole?

 

 

Thanks,

Andy

 

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31 minutes ago, andyr said:

 

Very cool, Simon!  :thumb:

 

Can you tell me what drill size you used for the main barrels?

 

Also, how did you make the notch in the side of the hole?

 

 

Thanks,

Andy

 

It’s 11.5mm just made with an 11.5mm drill bit. I started with 11 per the specs but it wasn’t quite big enough. I did the notch with a small jeweller’s file

Edited by RankStranger
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1 minute ago, RankStranger said:

It’s 11.5mm just made with an 11.5mm drill bit. I started with 11 per the specs but it wasn’t quite big enough. I did the notch with a small jeweller’s file

 

Thanks, Simon.  :)  Rather than all that filing ... I'm thinking I'll try drilling a second, small hole on the circumference of the big hole.

 

Andy

 

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20 minutes ago, andyr said:

 

Thanks, Simon.  :)  Rather than all that filing ... I'm thinking I'll try drilling a second, small hole on the circumference of the big hole.

 

Andy

 

Be careful because there’s not much between making a round hole big enough to take the square nub and being visible outside the circumference of the washer

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That's how they make those 4mm non-metal connectors out of Teflon - they first drill a 1mm hole (on the perimeter of a 4mm circle) then drill the 4mm hole for the insertion of a 4mm plug - gets a direct surface connection between the plug and a 1mm dia wire - can do with 2 or more wires of different diameters.

 

I tried this awhile ago but not sure if it made any difference in practice - more of an academic exercise about different metals, solders, bare wire, corrosion, contact coatings,  etc

Still quite keen on the 4mm BFA-Z plugs (beryllium copper) and sockets - a bit hard to find the plastic 'jackets' for them these days

 

 

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