mwhouston Posted May 9, 2020 Share Posted May 9, 2020 1 minute ago, planet10 said: As we well know, measured distortion does not even come close to being able to describe how a device sounds. You have to listen to them connected to real loudspeakers. And if youbelieved they were you wouldn’t be building amps & such with tubes. dave As above, not saying high distortion amps - like a lot of high power tube amps- don’t sound good they just aren’t high fidelity. But as an speaker building friend use to say; “pick the distortion profile you like and stay with it”. The fidelity “thing” never struck him me until I built my first Holton 300W amp and experienced utterly clear transparency. Once you hear it it’s hard to go back. Doesn’t stop me dropping in my 2W 6L6 SE UL power amp though for a week or so at a time. Link to comment Share on other sites More sharing options...
planet10 Posted May 9, 2020 Share Posted May 9, 2020 I have heard a number of very low distortion amplifiers, and they were all too often not very good. Each amplifier has to be considered on its own merit, driving loudspeakers — they ar e system, and one can often get lower measured distortion in compination than when measured separtly. On example is a low R[/sub]out[/sub] amp driving a speaker designed to be used with a high R[/sub]out[/sub] amplifier vrs a more suitable amp even thou the 1st can have measured distortin magnitudes lower lower than the 2nd. dave Link to comment Share on other sites More sharing options...
HdB Posted May 9, 2020 Share Posted May 9, 2020 “pick the distortion profile you like and stay with it”. That's pretty good "rule of thumb" for anyone Interesting thing - I got boards over from Tom Christianson (Neurochrome) to build his version of "ye ol' gainclone lm3886" amplifier using his exact BOM - the really surprising thing about this extraordinary low distortion version is how neutral it sounded - not flat and irritating like the old Crown and such "low distortion amplifiers", but a very nice sound indeed - not exactly my "cup of tea" into Fr drivers but never-the-less, a very pleasant surprise indeed - go figure. I have the 150W modules (NVx-200) for bass from Tassie - another low distortion amp that's excellent for bass - a tricked out F6 for mids/tops from >150Hz. (FAB, or WAW, Dave?) Glad to see your health is in the mend, Dave. 1 Link to comment Share on other sites More sharing options...
planet10 Posted May 9, 2020 Share Posted May 9, 2020 (edited) Tom brought his big 200w prototype to diyFEST one year. A really good sounding amplifier (but perhaps a touch to low an Rout to match my speakers, but skinny speaker wire should fix that. Not sure what FAB is, but the mains have been mostly our big A12pWeN/A7.3eN MTM WAWs. But there are. a few other WAW and alot of sngle (and double) driver FRs. When i get my diyAudio Store diy version of the FW B4, i’m going to swap these in (almost as good a sound, but prettier and the shape better suited to my room). This pic not my room. dave Edited May 9, 2020 by planet10 5 Link to comment Share on other sites More sharing options...
Bunno77 Posted May 9, 2020 Share Posted May 9, 2020 13 hours ago, planet10 said: I started out w Firstwatt when a friend loaned me his 1st gen ACA. I loved them. Then i got 2 newer ACA with a bit more power. Then a confluence of events allowed me to get a SIT-3 which is an incrediable amp. Curiousity has me wondering abou tthe ones i between like your F5. dave The F5 is a different beast to anything I have heard before. I understand why people say it is too bright but even with my speakers I was up until 4am listening last night so it isn't fatiguing. It is very impressive with good recordings and punishing to bad ones. In some ways it reminds me of my Halcro in detail retrieval it's not my perfect amp/sound but I am very happy with it and will tinker with it a little more and try the F6 or Aleph J when I can and swap them in If you have the itch and like the ACA and SIT-3 then go for it. It is great that many can be built in the same chassis with same PSU 1 Link to comment Share on other sites More sharing options...
pwstereo Posted May 9, 2020 Share Posted May 9, 2020 2 hours ago, planet10 said: Wow, those look like something from an aircraft factory. Beautiful form and construction. 3 Link to comment Share on other sites More sharing options...
planet10 Posted May 9, 2020 Share Posted May 9, 2020 Built by my partner Chris. After we got back together i wasn’t allowed to build cabinets, just design them :^) dave 1 Link to comment Share on other sites More sharing options...
HdB Posted May 9, 2020 Share Posted May 9, 2020 Yes Dan, the F5 has lots of good things about it - upgrading the power supply makes a big difference and also trying some of the 'audiophool' resistors in the signal path makes a big change too - you can "soften" it off a bit with a Cap Multiplier supply and the Manganin resistors and still maintain the high definition levels - maybe worth considering if you upgrade it. Sorry Dave, Full (ranger) with Assisted Bass - now knowns as WAW - I'll get there in the end! Marvelous craftsmanship, your speakers. 1 Link to comment Share on other sites More sharing options...
Bunno77 Posted May 9, 2020 Share Posted May 9, 2020 1 hour ago, HdB said: Yes Dan, the F5 has lots of good things about it - upgrading the power supply makes a big difference and also trying some of the 'audiophool' resistors in the signal path makes a big change too - you can "soften" it off a bit with a Cap Multiplier supply and the Manganin resistors and still maintain the high definition levels - maybe worth considering if you upgrade it. Good to know thank you. It is so time consuming reading through the DIY audio forums for what can be done. Do you mean just the transformer in regard to the PSU or the filter circuit too? Will look into resistors, cheers Link to comment Share on other sites More sharing options...
mwhouston Posted May 9, 2020 Share Posted May 9, 2020 4 hours ago, planet10 said: Built by my partner Chris. After we got back together i wasn’t allowed to build cabinets, just design them :^) dave Balance the hobby/job with life. Make everyone happy and you’ll be happy too. And you will be better creative. Link to comment Share on other sites More sharing options...
HdB Posted May 9, 2020 Share Posted May 9, 2020 Yeah Bunno, The F5 has been around quite a while now and many variations, yes, and much info to plow thru if you're so inclined. I found the basic F5 with Nichicon power caps and Dale resistors to be a bit bright for me so I started playing with it to change the sound to a softer sound without losing any details or transients to suit my system and ears - this may not be what you want to don't rush to make changes yet. There are currently a couple of projects about building Cap Multipliers power supplies for amps like these and these mostly drop 2 - 5 volts on each of the rails - if you have something like 24volts now (+/-24v), the drop won't make much difference to the amp's operation unless you're running inefficient speakers, a 'head-banger', etc so the existing transformer will be okay - the recommended size was 18v sec @ 300 va (for both channels) but many people have used either 2 trannies or a bigger 500va unit - if you're not using big amounts of power, stay simple for now. I found the bridge diodes did make a difference to the sound (but many people think I'm crazy - could be right too!) - I was happy with the MSRF 860s and 1560s but ended up with the low loss, low noise Shindengen Schottky bridges - only a small change. Resistors - I'd better mention now that some of these fancy resistors are a crazy price - the "U-beaut' naked Vishays (TC2575) are somewhere around $18 each and the Manganin ones I mentioned used to be around $6ea - you don't need many for this amp but it quickly adds up. It's something to maybe consider later or if you've built a Jim's Audio kit with Nova power caps, for example. 2 Link to comment Share on other sites More sharing options...
mwhouston Posted May 9, 2020 Share Posted May 9, 2020 After building a way over specced F5 for another in a 5U I would go for the two massive PSs and double (300VA) trannies but maybe cheap Rs. I also liked the thermistors on the 250V both active and neutral for surge protection. 1 Link to comment Share on other sites More sharing options...
THOMO Posted May 9, 2020 Share Posted May 9, 2020 (edited) Got a compactish full horn system up and running. I bought the bass horns which come from a Wireless World published design from 1970 .They are a folded horn which I am guessing were designed to be used in corners.These sat in my shed for a few months.Frankly I was not expecting much from them .I got around to replacing the 12 inch woofers with some Fostex FW305 s which I had already and which have been described as good in horns.The Edgar 500Hz tractrix midrange loaded with Dynaudio dome midranges and bullet tweeters I have had for over 20 years. What has surprised me is how low the bass goes in these.Even not in corners. I am measuring good bass down to at least 40Hz I was not expecting much below 100hz .And it is really good tight clean bass .[See in room response].Yes it needs some tidying up but the bass extension is surprising. Edited May 9, 2020 by THOMO 3 Link to comment Share on other sites More sharing options...
Bunno77 Posted May 9, 2020 Share Posted May 9, 2020 @HdB@mwhouston Thank you both. That is great info and made my research a lot easier. I have a 360VA Noratel and a 500VA Sedlbauer. The 500VA is going to be a tight squeeze to use current vertical mount so will probably need a layout change. Also have the Vishay bridge rectifiers so they are definitely going in soon. Yeah that is crazy prices for resistors but still relatively cheap compared to buying retail amps/upgrades so might be worth a try? Doubt my mismatched trannys is a good idea though. The F5 turbo would be something else. What are the insulators you used? The keratherm ones? This is my thermistor setup though not done by me 1 Link to comment Share on other sites More sharing options...
tuyen Posted May 9, 2020 Share Posted May 9, 2020 2-way multiple entry horn on top. Bipolar bass bottoms. A cowanaudio prototype. 8 Link to comment Share on other sites More sharing options...
mwhouston Posted May 9, 2020 Share Posted May 9, 2020 2 hours ago, tuyen said: 2-way multiple entry horn on top. Bipolar bass bottoms. A cowanaudio prototype. ? Link to comment Share on other sites More sharing options...
mwhouston Posted May 9, 2020 Share Posted May 9, 2020 3 hours ago, Bunno77 said: @HdB@mwhouston Thank you both. That is great info and made my research a lot easier. I have a 360VA Noratel and a 500VA Sedlbauer. The 500VA is going to be a tight squeeze to use current vertical mount so will probably need a layout change. Also have the Vishay bridge rectifiers so they are definitely going in soon. Yeah that is crazy prices for resistors but still relatively cheap compared to buying retail amps/upgrades so might be worth a try? Doubt my mismatched trannys is a good idea though. The F5 turbo would be something else. What are the insulators you used? The keratherm ones? This is my thermistor setup though not done by me Just bought a bunch of them myself. Link to comment Share on other sites More sharing options...
HdB Posted May 9, 2020 Share Posted May 9, 2020 Our Mr Cowan came up with some gems, eh - he did some really excellent amps too I'd suggest you stay with the single trannie if you can fit it - there's vertical brackets available or just get one of those heavy duty timber building brackets and knock the barb down - works like a charm. About those mains wires/thermistor connector, I'd suggest adding an insulating patch underneath - can't be too careful - also, those thermistor sometimes get really hot and you might need a ceramic connector - Jaycar keep them. The one resistor I'd suggest you play with is the 220R gate stoppers - if you can, get some Kao metal films for a slightly softer sound, or maybe Beyschlaggs (the Roe 'resista' ones) if you can find them - I've got some here if you want some. I have the keratherms but for some reason I still like using the messy 'goo' or those grey pads for temporary setup. Something else I've never managed well is the mounting bolts/washers for the power fets, plus, often changing the boards out, so I use those dual transistor clips (RS number 504-0609) and cut in half - the ridgid ones that work okay too. Link to comment Share on other sites More sharing options...
SumonKabir Posted May 10, 2020 Share Posted May 10, 2020 My first DHT preamp 3 Link to comment Share on other sites More sharing options...
mwhouston Posted May 10, 2020 Share Posted May 10, 2020 1 hour ago, SumonKabir said: My first DHT preamp Got a link for the kit? Link to comment Share on other sites More sharing options...
SumonKabir Posted May 10, 2020 Share Posted May 10, 2020 (edited) 23 minutes ago, mwhouston said: Got a link for the kit? https://simplepleasuretubeamps.wordpress.com/products/ Shiny Eyes 4p1L I have same power supply already. Edited May 10, 2020 by SumonKabir 1 Link to comment Share on other sites More sharing options...
kranky Posted May 11, 2020 Share Posted May 11, 2020 13 hours ago, SumonKabir said: https://simplepleasuretubeamps.wordpress.com/products/ Shiny Eyes 4p1L I have same power supply already. Another option for kit's using the 4P1L tube can be found at K&K Audio. Link to comment Share on other sites More sharing options...
SumonKabir Posted May 13, 2020 Share Posted May 13, 2020 Chasis in progress 3 Link to comment Share on other sites More sharing options...
Red MacKay Posted May 13, 2020 Share Posted May 13, 2020 Any pics of that 4P1L pre in action? Link to comment Share on other sites More sharing options...
SumonKabir Posted May 13, 2020 Share Posted May 13, 2020 19 minutes ago, Red MacKay said: Any pics of that 4P1L pre in action? Nope. This is 6SN7 pre with power supply in same chasis. 4p1L pre will need two Larger separate chasis. I am thinking supratek style two chasis. 1 Link to comment Share on other sites More sharing options...
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