itsparks Posted January 15, 2021 Share Posted January 15, 2021 3 minutes ago, mwhouston said: Agree that often there is way too much capacitance. I go for 80,000uf of 100v caps in my 300W Holtons. I can turn my power off and it will play for about 10 seconds after. I figure 80,000if is more than enough. I have been told by a professional amp builder that anything over 30,000if is useless. But funny thing is that they themselves have 250,000uf in their amps. It may just be a sales ploy I think. Also there is some evidence that having higher voltage caps than required provide better filtering/ storage. My caps are 100V for an 80V rail. My caps are dirt cheap but bass and transparency in my Holton amps is extremely good. And yes I snub all I can and add small polies (4.7 to 10uf) on the first cap and solder the bridge direct to the first cap for maximum current flow. What ever the hell I’m doing seems to work. Wait a second, you arn't using any speaker protection ? 1 Link to comment Share on other sites More sharing options...
aussievintage Posted January 15, 2021 Share Posted January 15, 2021 (edited) 11 minutes ago, mwhouston said: I have been told by a professional amp builder that anything over 30,000if is useless. Any rule of thumb is (virtually) useless. The criteria should be how much ripple you see under full load, and whether that is appropriate for the device being powered. 11 minutes ago, mwhouston said: Also there is some evidence that having higher voltage caps than required provide better filtering/ storage. Interesting. Link? Edited January 15, 2021 by aussievintage 1 Link to comment Share on other sites More sharing options...
mwhouston Posted January 15, 2021 Share Posted January 15, 2021 12 minutes ago, itsparks said: Wait a second, you arn't using any speaker protection ? No. Link to comment Share on other sites More sharing options...
mwhouston Posted January 15, 2021 Share Posted January 15, 2021 6 minutes ago, aussievintage said: Any rule of thumb is (virtually) useless. The criteria should be how much ripple you see under full load, and whether that is appropriate for the device being powered. Interesting. Link? I’ll see if I can find it. Link to comment Share on other sites More sharing options...
itsparks Posted January 15, 2021 Share Posted January 15, 2021 12 minutes ago, mwhouston said: No. I mean his amplifiers are really stable and i woulden't use a SSR either "BUT" the nice thing about his ssr is it disconnects the amplifier from the speaker when turned off so you don't get any dc into your speakers. IMO ribbon's die from these types of little dc spikes Link to comment Share on other sites More sharing options...
Batty Posted January 16, 2021 Share Posted January 16, 2021 3 hours ago, crtexcnndrm99 said: Interesting, thanks for the description. Also @Batty , is the sub for the ML-1s the new project? So many projects in that shot.. Sub is transmission line only 50 watt plate amp atm but power amp is only 25 watts so atm is enough. The standmounts are LK1 not ML1 1 Link to comment Share on other sites More sharing options...
mwhouston Posted January 19, 2021 Share Posted January 19, 2021 Hate is not a too stronger word when it comes to how I feel about tapping. The waltz I’m fine with but tapping, no way. 1 Link to comment Share on other sites More sharing options...
bob_m_54 Posted January 19, 2021 Share Posted January 19, 2021 13 hours ago, mwhouston said: Hate is not a too stronger word when it comes to how I feel about tapping. The waltz I’m fine with but tapping, no way. I can sympathise with that, when tapping aluminium (it's a bit like chewing gum). But in my last job, I'd probably tap between 20 and 50 holes a day, in stainless, and maybe that many in mild steel. Mostly between 3M and 6M threads. I found using the tap in a cordless drill on low speed, with plenty of cutting compound, was the easiest option. On harder metals (Staino or mild steel) I like Rocol, especially if using a cordless drill. For brass, copper and even aluminium I use Trefolex. And for small threads in ally, I sometimes just use WD40 or Ardrox Water Displacement Oil. 2 Link to comment Share on other sites More sharing options...
Steffen Posted January 19, 2021 Share Posted January 19, 2021 In the absence of specialised lubricants, I find that methylated spirit works well for tapping aluminium. It keeps the metal from sticking to the tool and itself. That’s what we were taught to use as apprentices some 40 years ago. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted January 19, 2021 Share Posted January 19, 2021 21 minutes ago, Steffen said: In the absence of specialised lubricants, I find that methylated spirit works well for tapping aluminium. It keeps the metal from sticking to the tool and itself. That’s what we were taught to use as apprentices some 40 years ago. After two office jobs lasting twenty years each and two retrenchment I worked in a factor for three months where we made massive industrial blinds. There I was taught turps was the preferred lube for tapping Al. I have turps but the sowing machine oil is on hand so I use it. Funny part is when this amp is complete the HSs run to near 40C and for the first few days all you can smell is the oil burning off. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted January 20, 2021 Share Posted January 20, 2021 Everyone has their preference and over the last three Holton builds (this is my seventh) I have used sticky silly pads. I know some like mica insulators etc. but after a very successful module to HS assembly I’m staying with the stickies. I spent a lot of time and extreme care marking, drilling and tapping the HS to ensure best FET to HS alignment for easy assembly. A new 2.5mm drill helped with tapping holes. By placing the stickies over the fasting bolt and adhering them to the back of the FET first. Then carefully bring them up to the HS and mounting the modules it was the very easiest and best I’ve ever ever done. Must remember this for next time. What an eighth Holton amp??.? I’d like to know who mounts thier modules high up, in the middle on the HS or low down and why? Any preference? 1 Link to comment Share on other sites More sharing options...
mwhouston Posted January 20, 2021 Share Posted January 20, 2021 Some assembly required. Cuppla days, doesn’t matter! 2 Link to comment Share on other sites More sharing options...
Batty Posted January 20, 2021 Share Posted January 20, 2021 In The centre, coz that is where the tapped holes were. 2 Link to comment Share on other sites More sharing options...
mwhouston Posted January 20, 2021 Share Posted January 20, 2021 5 hours ago, Batty said: In The centre, coz that is where the tapped holes were. So true. If some other idiot has gone to all the trouble to drill and tap I’d be using those holes to. Anyone who thinks electronics is a hot iron and cold beer has never made anything substantial. You have to get down and get dirty with drill presses, hacksaws, tin snips, sanders paint cans etc. Then the magic appears. 1 Link to comment Share on other sites More sharing options...
RankStranger Posted January 20, 2021 Share Posted January 20, 2021 41 minutes ago, mwhouston said: So true. If some other idiot has gone to all the trouble to drill and tap I’d be using those holes to. Anyone who thinks electronics is a hot iron and cold beer has never made anything substantial. You have to get down and get dirty with drill presses, hacksaws, tin snips, sanders paint cans etc. Then the magic appears. oh, man. I can solder to get me by but all that other stuff is what keeps me coming back 1 Link to comment Share on other sites More sharing options...
RoHo Posted January 22, 2021 Share Posted January 22, 2021 New miniDSP 2x4 HD with DIY valves. I like it both ways. 2 1 Link to comment Share on other sites More sharing options...
Batty Posted January 22, 2021 Share Posted January 22, 2021 DV676? DVD player or close. I have the same player in the shed, great little unit. Getting there..... 1 Link to comment Share on other sites More sharing options...
RoHo Posted January 22, 2021 Share Posted January 22, 2021 6 minutes ago, Batty said: DV676? DVD player or close. I have the same player in the shed, great little unit. Getting there..... Yep, the Toslink output is coming in very handy. Link to comment Share on other sites More sharing options...
Batty Posted January 22, 2021 Share Posted January 22, 2021 nice little cheapo transport Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted January 22, 2021 Share Posted January 22, 2021 19 minutes ago, RoHo said: New miniDSP 2x4 HD with DIY valves. I like it both ways. What’s the component in the middle.? Think I see a tamura transformer and el84s Link to comment Share on other sites More sharing options...
RoHo Posted January 22, 2021 Share Posted January 22, 2021 23 minutes ago, crtexcnndrm99 said: What’s the component in the middle.? Think I see a tamura transformer and el84s It’s a Pre-amp, Allen Wright’s FVP5A circuit. Valves are Russian 6n6p. The transformer is a James from Taiwan. Sadly they closed down a few years ago. Good quality and much more affordable than the classy Japanese trafos like Tango and Tamara 1 1 Link to comment Share on other sites More sharing options...
Red MacKay Posted January 22, 2021 Share Posted January 22, 2021 (edited) James Trannies no more? That's a shame. What are the tubes in your amp? Edited January 22, 2021 by Red MacKay Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted January 22, 2021 Share Posted January 22, 2021 13 minutes ago, RoHo said: It’s a Pre-amp, Allen Wright’s FVP5A circuit. Valves are Russian 6n6p. The transformer is a James from Taiwan. Sadly they closed down a few years ago. Good quality and much more affordable than the classy Japanese trafos like Tango and Tamara Ah interesting, cheers Link to comment Share on other sites More sharing options...
RoHo Posted January 22, 2021 Share Posted January 22, 2021 26 minutes ago, Red MacKay said: James Trannies no more? That's a shame. What are the tubes in your amp? The power amp uses 6cb5a, cheap TV tubes. I found out about them from Thomas Mayer’s Vinyl Savor blog. He wired them as triodes, traced the curves and reckoned they were as linear as a 300B. At 10 bucks each....shut up and take my money!! The input stage is another Allen Wright design, from his PP2C power amp and uses 6H30 tubes 2 Link to comment Share on other sites More sharing options...
Red MacKay Posted January 22, 2021 Share Posted January 22, 2021 1 hour ago, RoHo said: The power amp uses 6cb5a, cheap TV tubes. I found out about them from Thomas Mayer’s Vinyl Savor blog. He wired them as triodes, traced the curves and reckoned they were as linear as a 300B. At 10 bucks each....shut up and take my money!! Nice..... I love seeing whacky tubes being used. Well Done! 1 Link to comment Share on other sites More sharing options...
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