Search found 747 matches

by RhythMick
Sun Mar 05, 2023 5:48 pm
Forum: Everyones Projects
Topic: Ground fault in old CD player?
Replies: 3
Views: 4000

Re: Ground fault in old CD player?

Not sure what you mean about meter resistance. 70mv is more than enough to generate the 30ma that will trip the rcb. I would check any live to case caps in the ac input of the teac. Maybe worth looking at the 70mv with a scope to see just what sort of shape the DC is. Ok thanks for input Nick, I've...
by RhythMick
Sun Mar 05, 2023 2:16 pm
Forum: Everyones Projects
Topic: Ground fault in old CD player?
Replies: 3
Views: 4000

Re: Ground fault in old CD player?

I thought of another explanation, a fault in the Variac earth post connection. Unlikely because the Variac wasn't in circuit when it first tripped.

Eliminated by using a different earth post.
by RhythMick
Sun Mar 05, 2023 2:09 pm
Forum: Everyones Projects
Topic: Ground fault in old CD player?
Replies: 3
Views: 4000

Ground fault in old CD player?

I was testing a passive balanced preamp I've built for a friend, but on playing music through it and attempting to scope the output my RCD trips. I was taking a balanced output from an old TEAC VRDS player and after much elimination I think I've identified there's a ground fault somewhere in the TEA...
by RhythMick
Fri Mar 03, 2023 2:04 pm
Forum: Computer Audio
Topic: Streaming DAC/ Pre with Balanced Outputs
Replies: 7
Views: 6912

Re: Streaming DAC/ Pre with Balanced Outputs

Me too ref all these ultra neat solid state builds. My projects going forward only in my head of course are: Must build an AD1 amp….. Must build with those idh valves a bit like px4 Must build another 6em7 amp something about it dht’s cant do Must cut the magnet off my ae1’s and bolt on a field coi...
by RhythMick
Fri Mar 03, 2023 7:51 am
Forum: Computer Audio
Topic: Streaming DAC/ Pre with Balanced Outputs
Replies: 7
Views: 6912

Re: Streaming DAC/ Pre with Balanced Outputs

Check out Tony's 'New Dilemma' thread https://www.audio-talk.co.uk/phpBB3/viewtopic.php?t=8633 I've been watching those DAC build threads, fascinating but it took me years to get my head around valves, I think that fiddly stuff is beyond me. My soldering tool of choice is a D24 Hakko bit. Although ...
by RhythMick
Wed Mar 01, 2023 5:10 pm
Forum: Computer Audio
Topic: Streaming DAC/ Pre with Balanced Outputs
Replies: 7
Views: 6912

Re: Streaming DAC/ Pre with Balanced Outputs

Nick wrote: Wed Mar 01, 2023 9:02 am
I think Nick of this parish manufactures or did at one time
I did, but it was very much a DAC, no volume control, no apps, certainly no streaming :-)
Ok thanks Nick worth asking.
by RhythMick
Wed Mar 01, 2023 8:34 am
Forum: Computer Audio
Topic: Streaming DAC/ Pre with Balanced Outputs
Replies: 7
Views: 6912

Streaming DAC/ Pre with Balanced Outputs

Hi all. My main system, which uses my DIY power amp with balanced inputs, uses the Cambridge Audio Azur 851N for all digital sources. It's a very convenient device, with multiple digital sources, network streaming and volume attenuation. I very much like the sound, though of course I'm always up for...
by RhythMick
Mon Feb 06, 2023 8:43 pm
Forum: Valves
Topic: What are the oldest affordable valves you can still buy?
Replies: 13
Views: 8203

Re: What are the oldest affordable valves you can still buy?

I use old globe DHT triodes for my builds and I have quite a boxes of Cunningham, RCA, and many others dating from 1920s, 30s. My opinion they sound great, I like the 26 for input with 71A driver and 45 output. 01A are similar to 26 with half the anode current and there are absolutely tons of them d...
by RhythMick
Wed Jan 18, 2023 8:09 am
Forum: Everyones Projects
Topic: Fun with Feedback
Replies: 239
Views: 54621

Re: Fun with Feedback

Cressy Snr wrote: Fri Jan 06, 2023 10:24 pm Ooh look! Pentodes in the parlour (good name for an arty band) you know, just to see how it sounds with the Mission 773 floor standers like:
73E179F8-08DE-4414-A353-DF10215E41E7.jpeg
Nice build. Late query. I like the circular grill valve bases, where are they from?
by RhythMick
Sun Jan 15, 2023 9:45 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

In this page...http://www.valvewizard.co.uk/heater.html Merlin Blencowe states... Rule number one is that the heater supply must have a DC connection to audio ground. This may be a direct connection or an elevating circuit (see shortly). This is equally true for AC or DC supplies. Leaving the heater...
by RhythMick
Sat Jan 14, 2023 9:37 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

I'm still intrigued by the original fault. The missing earth connection can't have caused that can it?
by RhythMick
Sat Jan 14, 2023 8:50 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

Good to have a variac. One problem might be that getting a Champ right in the first place might be part of the process. Guitar amps are not like hifi amps. If you build something hifi-ish and put a guitar through it, it can sound pleasant. But guitar amps have enormous gain and Champs use one valve...
by RhythMick
Sat Jan 14, 2023 7:58 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

And the final test for tonight, with plate connections restored and secondary fuses in place, DC voltage across the bleed resistor measures 452V with about 160mV ripple.
by RhythMick
Sat Jan 14, 2023 7:51 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

Did the fuse go on the wind up from 0? I'll repeat the test. I may have only done the wind up with heaters only, which was successful. Interesting. Firstly, after a rest I reviewed the physical connections against the circuit I posted. The earth to power ground was missing. I added that (at the far...
by RhythMick
Sat Jan 14, 2023 7:45 pm
Forum: Everyones Projects
Topic: Help before I lose my sanity
Replies: 17
Views: 7897

Re: Help before I lose my sanity

This may not be helpful but having built several 'fender champs' the 'simple' psu is a feature of its erm, magic. One ecc83 and one el84 ( or 6sl7/ 6v6) really doesn't need much to get rocking but otoh it is only a tiny on/off sort of amp. 8 inch speaker sounds crap too! The fender deluxe is hugely...