New Posts New Posts RSS Feed - 1970s Design Indulgence
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Welcome to the Graham Slee Audio Products Owners Forum

 

Open to all owners plus those contemplating the purchase of a Graham Slee HiFi System Components audio product and wishing to use this forum's loaner program: join here (Rules on posting can be found here)

This website along with trade marks Graham Slee and HiFi System Components are owned by Cadman Enterprises Ltd


1970s Design Indulgence

 Post Reply Post Reply Page  <1 343344345
Author
RichW View Drop Down
Senior Member
Senior Member


Joined: 21 Jan 2013
Location: UK
Status: Offline
Points: 1471
Post Options Post Options   Thanks (0) Thanks(0)   Quote RichW Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2024 at 10:34am
Hi Jon,

A loan of the 7eventy would be great - can I get in touch in a few weeks?
Thanks.


Majestic/Enigma, Accession MM & MC.
Back to Top
dave View Drop Down
New Member
New Member


Joined: 04 Sep 2023
Status: Offline
Points: 3
Post Options Post Options   Thanks (0) Thanks(0)   Quote dave Quote  Post ReplyReply Direct Link To This Post Posted: 31 Jan 2024 at 12:36pm
Originally posted by Graham Slee Graham Slee wrote:

In all unregulated single supply transistor power amplifier circuits, the output's DC level is bound to change gradually with load. Now, where have I heard that before? I haven't!

Why didn't JLH say it? Did Self say it and I didn't understand? All they ever said was the output capacitor caused distortion, as well as saying class-B causes distortion.

JLH did say that it appears that there's more bass when a regulated power supply is used, but without explanation.

All I did was put a DVM between the OP stage DC and ground, and swept the signal amplitude up and down, and noticed how the DC changed with the droop on the HT (due to load).

And all I've done (with Bruce's measure thrice to the power of lots - to cut once) is to stop that happening by giving the voltage stage a regulator.

But I do understand they didn't have TL783's in the 60's or 70's, after which amplifier design had moved on anyway. And here it only just fits the required voltages. And you do have to fully grasp what a bootstrap does (negative current on positive swings).

It hasn't broke yet after being on for 24 hours, so I hope it has dealt with the unmeasurable distortion my ears were complaining of.


humour me several years out of time.... This is very exciting, and a personal preoccupation of mine. don't like seeing cones flapping around, and I have unstable mains in my house to add to the joy. It gets everywhere, so I try and regulate / stabilise input / driver stages in my tube amps when ever I can. 

Must read on to see how it sounds. The suspense :)
Back to Top
Fatmangolf View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 23 Dec 2009
Location: Middlesbrough
Status: Offline
Points: 8960
Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 31 Jan 2024 at 1:44pm
Originally posted by RichW RichW wrote:

Hi Jon,

A loan of the 7eventy would be great - can I get in touch in a few weeks?
Thanks.



That works for me Richard.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
Back to Top
 Post Reply Post Reply Page  <1 343344345
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.141 seconds.