Search found 514 matches

by RhythMick
Sat Aug 24, 2019 4:07 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1094
Views: 104055

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

I just finished 6 of the boards. All test well except 1, which produces the right voltages but behaves differently. By which I mean it goes directly to the set voltage without the slow start, and adjusting the trimmer pot gives an immediate reaction where the others move more slowly. I can check sol...
by RhythMick
Tue Aug 20, 2019 3:11 pm
Forum: Valves
Topic: Recommendations needed for high quality valve bases
Replies: 0
Views: 71

Recommendations needed for high quality valve bases

The last valve bases I used looked great (black bakelite) but have screw in pins. I thought that was a benefit until I overtightened a couple after they kept coming loose.

So I'm after recommendations. Ideally copper or gold plated copper contacts, ceramic for low capacitance. What do you all use?
by RhythMick
Tue Aug 20, 2019 3:08 pm
Forum: Beginners
Topic: Help interpreting 2nd/3rd Harmonic values on WE datasheet
Replies: 11
Views: 161

Re: Help interpreting 2nd/3rd Harmonic values on WE datasheet

Many many thanks. I use a calculator called HandyCalc on Android and it allows me to create functions which are really quick and easy. I'll create one for this.
by RhythMick
Tue Aug 20, 2019 9:14 am
Forum: Beginners
Topic: Help interpreting 2nd/3rd Harmonic values on WE datasheet
Replies: 11
Views: 161

Re: Help interpreting 2nd/3rd Harmonic values on WE datasheet

Nick wrote:
Mon Aug 19, 2019 9:53 pm
Yes, so for example 40dB is 1%, 20dB is 10%
Ok thanks Nick. How do you convert dB to %
by RhythMick
Mon Aug 19, 2019 9:44 pm
Forum: Beginners
Topic: Help interpreting 2nd/3rd Harmonic values on WE datasheet
Replies: 11
Views: 161

Help interpreting 2nd/3rd Harmonic values on WE datasheet

I stumbled across a WE datasheet for the 300B which included a table of operating points showing 2nd and 3rd harmonics, expressed in dB. Screenshot attached. Now I'm reasonably competent with maths, but will readily accept to dB being a weakness of mine. As a measurement it's a ratio, right ? So in ...
by RhythMick
Mon Aug 12, 2019 8:36 am
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

Ok I overstated. Fair cop. I'm well chastised. "Everything should be made as simple as possible, but not simpler" isn't right either - it references what's possible but not what is optimal. And of course everyone will have their own view of what is optimal. I was simply trying to say that if it work...
by RhythMick
Sat Aug 10, 2019 2:18 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

Simplicity rules
by RhythMick
Sat Aug 10, 2019 12:49 am
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

I'm a ways behind you in terms of really developing my understanding of the behaviour of my amp in all conditions. However my ears have told me similar things. I prefer the sound of interstage coupled, all DHT, PP architecture. I prefer to minimise caps in favour of iron and I instinctively avoid si...
by RhythMick
Fri Aug 02, 2019 10:01 am
Forum: Everyones Projects
Topic: Guitar Amp for Granddaughter
Replies: 22
Views: 933

Re: Guitar Amp for Granddaughter

Plus I'm sorry but I haven't heard any digital amp sound anything like as good as a proper valve amp. Call me old fashioned. No, but they can sound 95% as good as 20 amps and 20 cabs, and a floor full of pedals, are easy to carry to gigs, can sound good at both bedroom practice and playing with dru...
by RhythMick
Fri Aug 02, 2019 8:01 am
Forum: Everyones Projects
Topic: The Nemesis 813 PP Amplifier
Replies: 332
Views: 19203

Re: The Nemesis 813 PP Amplifier

OK, so one side ( 'E' ) is connected to the 440R resistor ( or a suitable value for 4P1L's ) and you can connect one Lehane supply across E-F ? I think things have moved on a bit from that post due to Paul's comments. I will need 2 Lehane regs but quite how I use them is up for grabs at the moment....
by RhythMick
Thu Aug 01, 2019 10:26 pm
Forum: Everyones Projects
Topic: Guitar Amp for Granddaughter
Replies: 22
Views: 933

Re: Guitar Amp for Granddaughter

Thanks Nick/Ed, That Blackstar looks awesome :D @Ed I can’t justify building something when that Blackstar exists, so I guess that’s that. Bloody digital! Is nothing sacred? :lol: Sure you can. You'd enjoy the design and build, and how much better to be able to give your granddaughter a hand built ...
by RhythMick
Tue Jul 30, 2019 12:56 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

I would also be worried about those SMPS directly connected to the TX that serves the GM70 bias. Aren't they really noisy?
by RhythMick
Sun Jul 28, 2019 10:07 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

Just a thought Steve, but with my transformer coupled all DHT PP amp I started with shared cathodes and found a big improvement from switching to separate (bypassed) cathodes. Maybe something to try one day, if you do I'd be interested in the result.
by RhythMick
Fri Jul 26, 2019 8:02 am
Forum: Everyones Projects
Topic: Guitar Amp for Granddaughter
Replies: 22
Views: 933

Re: Guitar Amp for Granddaughter

Sounds great and is a project I'm interested in myself. Most amps are way over powered and as a result never get used in that wonderful sweet spot where the output stage starts overdriving. That's where the brown sound lives. I have it on my list to create a flea powered amp. I'd be very interested ...
by RhythMick
Wed Jul 17, 2019 9:02 am
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2348

Re: GM70 PP

Well, if its regulated, one end will be the emitter of a transistor, the other the ground or a sense resistor for the supply. Remember Mark found that he could hear the cap in the integrator. It may also be a case that connecting the resistor may alter the conditions the DC supply sees. Both intere...