Author Topic: Sugden a21  (Read 912 times)

Offline ALF

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Sugden a21
« on: May 11, 2018, 03:27:16 PM »
Just a few pictures of this lovely vintage amp that I am busy with re capping and a few upgrades, this might be very old but play as smooth as class A single ended can be

"the fostex thang".....

Offline grumpybear

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Re: Sugden a21
« Reply #1 on: May 12, 2018, 12:06:48 PM »
Lovely old amp and cosmetically great as well.

We used to sell these with B&W DM2a or DM4s and usually with a Thorens TD124/SME/Shure V15 and the package sounded just great.

Offline afroaudio

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Re: Sugden a21
« Reply #2 on: June 13, 2018, 08:23:29 PM »
I think this was mine... via fredeb?? Regardless great to see this been given a new lease of life with fresh caps and bridge rectifier etc.. Hope you enjoy for many years to come!  :dop:

Offline Agaton Sax

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Re: Sugden a21
« Reply #3 on: June 13, 2018, 08:48:38 PM »
I posted this elsewhere. The speakers discussed was a pair of  QUAD corner ribbons.

I heard a pair years ago in a wonderful non-audio room with timber floors,overstuffed leather couches and thousands of books and cds everywhere. Amp was an ancient Sugden a21. No idea what the source was or how to describe the sound in hifi terms but it was one of the most pleasant music listening evenings l ever had.
« Last Edit: June 13, 2018, 08:56:31 PM by Agaton Sax »

Offline ALF

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Re: Sugden a21
« Reply #4 on: June 22, 2018, 01:32:54 PM »
This was one of Andre`s amps that he was hiding away from me for a long time, I think my timing was good to take this amp over from him.
Because he loves this specific little amp so much I need to treat her with respect if it comes to upgrading & modifying and to keep it close to original but also try to get the best out of this old design. ( adopting some of Nelson Pass amp technics )
Currently I disconnected the internal pre amp just by pulling out a DIN cable to the main amp and connected the main amp to the back DIN connectors and using the amp as a power amp only, the reason is I do have a very nice Hafler HD101 and it sounds better with the Hafler that its own noisy pre stage.
Next upgrade will be a CRC setup for the power supply and Silver Mica for the Feedback cap, the only other upgrade would be to swap out those old resistors to new metal and carbon films but that might rob the original sound signature of this vintage amp.

Maybe some advice on signal resistor upgrading ??
"the fostex thang".....

Offline marantz123

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Re: Sugden a21
« Reply #5 on: June 22, 2018, 03:20:03 PM »
This amp has carbon composite resistors in the signal path. If these resistors (normally 10% tolerance) are within spec, or up to +-15%, then they are most probably ok. If out of spec, replace with carbon film 0.5w 5%. This is the most affordable and will keep the amp closest to the sound signature. Its a classic vintage piece and to keep its value and vintage sound signature, one should only change what needs to be changed. Its a personal choice though. Changing electrolytics, and if needed, upgrading to better safety capacitors is probably where I would go. Have personally experimented with revoicing preamp stages with metal film resistors and its just not a vintage amp anymore. I stress again...its a personal choice and up to the owner to decide what he wants to do with a classic amp, but respect for the original signature and maintaining the value of the piece should be considered.

Offline Agaton Sax

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Re: Sugden a21
« Reply #6 on: June 22, 2018, 03:44:02 PM »
Some of the biggest stuff-ups I made in audio was replacing vintage parts with modern-especially resistors but also wiring and un-sympatheticaly chosen capacitors. Suddenly a rich full sounding  vintage amp becomes a thin,lean sounding  piece of mid-fi mediocrity.

 Tonmeister? Not easy.

Offline Hi-Phibian

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Re: Sugden a21
« Reply #7 on: June 22, 2018, 04:19:15 PM »
Some of the biggest stuff-ups I made in audio was replacing vintage parts with modern-especially resistors but also wiring and un-sympatheticaly chosen capacitors. Suddenly a rich full sounding  vintage amp becomes a thin,lean sounding  piece of mid-fi mediocrity.

 Tonmeister? Not easy.


Spot on.
Proprietor of Croak Audio Exploration.
Fair, not crazy, cash paid for turntables and tonearms from Rega, Linn and Thorens.          http://www.croak.co.za

Offline marantz123

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Re: Sugden a21
« Reply #8 on: June 22, 2018, 05:09:55 PM »
Have a friend who many years ago changed resistors in his Quad2's and to this day he cries about it because at some point, wifey threw the "old" resistors away. He says that the amp lost its vintage colour signature, sterile sounding n was an appreciable difference in sound for a while. I feel his pain
.shame. If u have something with CCR's in them...think twice abt changing them out....it'll never sound the same.

Offline ALF

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Re: Sugden a21
« Reply #9 on: June 23, 2018, 09:42:48 AM »
I do agree 100% on that I will keep resistors as is, I just swapped the low value high watt resistors to new Vishay more stable resistors. I would love to A/B this old amp against some newer amps on HE type of speakers 94db and up because I am sure this amp punch very high up in the ranks.
"the fostex thang".....

Offline 2phat

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Re: Sugden a21
« Reply #10 on: July 21, 2018, 12:10:09 PM »
Really lovely! I had one in the 80's and sold it to buy crap!

Great amp!