Search found 894 matches

by JamesD
Fri May 28, 2021 3:07 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

DP-1000 is a nice DD motor unit but this looks like the right/top price to me as its a 110V unit and no arm.... having said that, serious vintage DD turntable prices are going up worldwide... But its up against things like the JVC QL-A7 which has a decent arm is 240V and is semi-auto for £450.00 to ...
by JamesD
Fri May 28, 2021 12:45 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

And here is the JVC
JVC QL-A7-2.png
JVC QL-A7-2.png (190.13 KiB) Viewed 1217 times
JVC QL-A7.png
JVC QL-A7.png (181.77 KiB) Viewed 1217 times
and close up of the AT cartridge
AT450E.png
AT450E.png (85.84 KiB) Viewed 1217 times
by JamesD
Fri May 28, 2021 12:43 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

I promised some pictures... Here is the Optonica (Sharp) Optonica RP7100.png Optonica RP7100.png Optonica RP7100.png One interesting observation about this deck is that the surface noise is more noticeable with this deck than any of the others and that is consistent with it being a lessor performer ...
by JamesD
Thu May 27, 2021 5:01 pm
Forum: Valves
Topic: SRPP stage useing a 5670
Replies: 19
Views: 5332

Re: SRPP stage useing a 5670

Does this make sense? With 6 mA quiescent current it could in theory in Class A swing from 0mA to 12mA so its not constant current but in practise the active device needs some headroom to stay in its linear region... so higher distortion as it gets nearer the current swing extremes and this swops be...
by JamesD
Thu May 27, 2021 2:48 pm
Forum: Valves
Topic: SRPP stage useing a 5670
Replies: 19
Views: 5332

Re: SRPP stage useing a 5670

Indeed - am I missing something? I think if you drive 14.14 V across 2500R you need 5.6mA that leaves 400uA for the triode - look at that on a 6922 plate curve and its well into the lower curvature region yielding high distortion - I know the SRPP is effectively PP but the valve is still pulled into...
by JamesD
Thu May 27, 2021 2:02 pm
Forum: Valves
Topic: SRPP stage useing a 5670
Replies: 19
Views: 5332

Re: SRPP stage useing a 5670

Ian, Many thanks for the reply - a shame your more detailed one was lost as I have enjoyed your longer posts on DiyAudio. I'm a Broadcast Engineer myself and have worked both Video and Sound - on the Sound side from valve EMI mixers, etc. forward so I appreciate the control of power draw in valve ci...
by JamesD
Wed May 26, 2021 2:46 pm
Forum: Everyones Projects
Topic: music production
Replies: 34
Views: 6034

Re: music production

What is established for hearing is the extent to which emotional state affects audio judgement and the unconscious bias that it generates during blind testing sessions and that this increases the longer a session continues and as the number of test samples increases... This is not an argument for Go...
by JamesD
Wed May 26, 2021 2:37 pm
Forum: Valves
Topic: Another insane valve for phonos
Replies: 12
Views: 4114

Re: Another insane valve for phonos

Thats a damn good point - particularly with the way that 1/f noise in a valve has a corner frequency ~ 1KHz rather than the 50Hz or lower that good low noise bipolars have...
by JamesD
Wed May 26, 2021 2:17 pm
Forum: Valves
Topic: SRPP stage useing a 5670
Replies: 19
Views: 5332

Re: SRPP stage useing a 5670

Hi Ian, I find I agree with JRB far more than I disagree with him... but that's just me and for an engineering subject audio circuit and system design is certainly a broad church.. His SRPP article has always drawn a lot of comment and criticism.. Welcome here, btw, its great to have another experie...
by JamesD
Tue May 25, 2021 7:24 pm
Forum: Valves
Topic: SRPP stage useing a 5670
Replies: 19
Views: 5332

Re: SRPP stage useing a 5670

Tubecad explaining what the SRPP stage is, how to design it and why not to bother except for some limited use cases :D

https://www.tubecad.com/may2000/

ciao

James
by JamesD
Tue May 25, 2021 5:14 pm
Forum: News
Topic: Patrick Turner
Replies: 2
Views: 1042

Re: Patrick Turner

A really big loss - I learned a lot from his pages and he had a really interesting take on how to setup pentode power valves for optimum quality/efficiency...
by JamesD
Tue May 25, 2021 3:11 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

I have had a play with the Optonica (Sharp) RP-7100 deck and it is better with the Ortofon M20E Super cartridge than the Audio Technica AT450E by about the same amount as the Kenwood is. It sounds like an 90% version of the Kenwood deck - mainly due to the arm being limited in quality. Its a strange...
by JamesD
Tue May 25, 2021 2:32 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

Good luck with the jab Mark!!!

It wasn't much fun but at least I didn't feel ill just exhausted... and miles better than getting COVID!

Got some design work completed for the mc head amp so its now ready to build rather than just a circuit simulation... might get it done in a week or so...
by JamesD
Fri May 21, 2021 8:09 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

Sorry to be quiet for a bit - I had my second COVID jab and went to sleep for a week and then no energy for another week... Feeling better the last couple of days - thank goodness... So synergy... I now understand Ants love for the Audio Technica MM cartridges... after finding them second place to t...
by JamesD
Mon May 03, 2021 8:17 pm
Forum: General Vinyl
Topic: Vinyl playback and synergy...
Replies: 26
Views: 3521

Re: Vinyl playback and synergy...

Hi Mark, Interesting observation on the platter construction... but both Kenwood and AIWA have single piece cast and machined metal oversized platters with a thick 'rubber' mat - the Kenwood is heavier but not by a lot with a flat platter surface and flat rubber mat over the playing surface. The Aiw...