Search found 7769 matches

by Paul Barker
Mon Nov 29, 2021 9:16 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Ray and I were togetherat VSAC was it in 2003? I know we all look a lot different, peoples films and stills of me at first eggborough show a much younger looking person without hardly any lines. But I saw this character 18 years on showing really deep analytical sort of conscentration interest in al...
by Paul Barker
Mon Nov 29, 2021 9:01 am
Forum: Everyones Projects
Topic: Poundland 45
Replies: 146
Views: 9048

Re: Poundland 45

I have never seen Steve do what I find is needed for regulated supplies, add a small resistor (say 5-10 ohm) feeding a high quality film cap (say 1uf) on the output to isolated the HF from the regulation. Just saying. The chip manufacturers used to show this on their suggested schematics. Possibly ...
by Paul Barker
Mon Nov 29, 2021 8:48 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Ray P wrote: Sun Nov 28, 2021 9:33 pm Good stuff Paul, I can picture you with a nice big grin now...
You know me well OB1
by Paul Barker
Sun Nov 28, 2021 6:10 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

I’ll take youre analysis, thank you Nick. Im going to see if I have any knickel laminations to fit these Hammond’s, possibly not , and they may have to parafeed, though perhaps with 15mA the Nickel lams will stand up to dc. I haven’t! No repeatable sources either. I bought my Niclel lams on eBay, no...
by Paul Barker
Sun Nov 28, 2021 4:44 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Here is the data, showing as 3 watts but it’s two valves per channel, so 6 watts. Distortion profile showing less than 1/2 a percent. https://i.postimg.cc/mZPLngnc/5190-A1-E0-FFDE-4-C4-D-8148-E1416-BD93-C6-E.png https://i.postimg.cc/65R991tt/6-F661-FC2-52-C5-46-B2-8-A7-A-35-FDE765241-C.png https://i...
by Paul Barker
Sun Nov 28, 2021 4:33 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

This amp is so good I seriously might go into production and sell them through Dave. After Ive found current production valves of a quality not lacking.
by Paul Barker
Sun Nov 28, 2021 4:29 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Bartoli Valves, quoting Andy Evans, who I dont know, understated the phsing issue of Hammond IT’s. It copletely ruins the sound, they should come with a HMgov warning like bacca!

They are grossly wrong out of phase!

Which makes you look a pratt at Owston!
by Paul Barker
Sun Nov 28, 2021 4:17 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

It was the IT phasing. I also changed the D3a cathode resistor @15mA. Those remaining this morning heard it was fixed. At home now I take it back Ant, the speakers you gave me are very good match for this amp. I’m using cheap Chinese titanium compression bullet tweeters about £35 delivered from Chin...
by Paul Barker
Sun Nov 28, 2021 7:59 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

I’ve found suitable resistor to bias D3a at 15mA. Discovered AE interstate is 50mA tolerant , but inductance halted compared to Hammond. So I’ll put in the bias alteration and correct phase of of Hammond first. I’ll take the AE’s in case that doesn’t work. https://i.postimg.cc/gjLgrrzt/152-D110-C-C7...
by Paul Barker
Sun Nov 28, 2021 7:10 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Turned out to recess the voicing significantly and rolled off chronically. Early hours today googled for phasing issues as Andrew Le and Nick both in help mode independantly suggested phase issues. Up early doors today and found at Bartoli Valves and found “ Andy Evans suggested that secondary green...
by Paul Barker
Fri Nov 26, 2021 11:22 pm
Forum: Assorted Stuff
Topic: Owston ‘21: What Are You Bringing?
Replies: 43
Views: 1751

Re: Owston ‘21: What Are You Bringing?

As of just now, 801a amp is coming, warts and all.
by Paul Barker
Fri Nov 26, 2021 11:20 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

It’s finished it’s safe the operating point is bang on with normal mains voltage. Obviously I brought it up on the variance. Found it beneath the operating voltage maybe 10 v at variacs max. So plugged direct to mains took it to bang on. 72mA two valves plate voltage 561 620 ohm resistor combined pa...
by Paul Barker
Fri Nov 26, 2021 11:11 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

Wish the opts had same inductance as that choke. But at 27h for one, 30h the other (you’d be quite shocked how common that variance is, hardly any Leak Stereo 20 opts match but nobody ever hears the variance) likewise these transformers were used on the best sounding amp I’ve ever hooked up. The oth...
by Paul Barker
Fri Nov 26, 2021 8:59 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 95
Views: 4806

Re: 801a amplifier

If I’m to get this done, need to start with a clean up. https://i.postimg.cc/NF35c3TW/30-C8-F7-EB-EA74-4161-AB38-F4-CB1-A14-AF50.jpg https://i.postimg.cc/1R2gwqTJ/6-F055-A8-F-30-DA-4-D74-A0-CC-84-AD977-D7027.jpg https://i.postimg.cc/63Q7LLt1/724-CC3-EC-7284-4-CF5-940-F-78-B614925-DD6.jpg
by Paul Barker
Fri Nov 26, 2021 6:35 am
Forum: Assorted Stuff
Topic: Owston ‘21: What Are You Bringing?
Replies: 43
Views: 1751

Re: Owston ‘21: What Are You Bringing?

As a matter of knowledge sharing Ive decided to bring more Glass Audio comic’s on trust that noone blatantly publicly ignores copyright, or forgets to put them back. I have just those, I have done no copies, so don’t forget they are a reading resources while youre there only. There is one extremely ...