Yorkshire Hi-Fi Club

Subjects that don't have their own home
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#346 Re: Yorkshire Hi-Fi Club

Post by Nick »

Some info. Ali left the Modwright phono with me. Measurements are interesting. The RIAA has a rising response above 2k, will post some graphs later, one channel shows a rising response below 500Hz as well, but the other shows a falling response. I will investigate further. Distortion also shows much higher on one channel (0.12% against 0.06% at 1v output 1kHz), so the two things may be related and might be a valve issue, I will do some swapping later today and see what I find.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
JohnG
Old Hand
Posts: 418
Joined: Sat Mar 25, 2017 10:59 am

#347 Re: Yorkshire Hi-Fi Club

Post by JohnG »

Being one who was very impressed with the performance of the the ModWright presented by Ali.
Are the measurements being reported a falling away from the as new models measurements ? .
Would it be possible to report back if any works carried out, have a audible effect on the sound quality that can be heard, if corrections that are deemed required are put into place ?.
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#348 Re: Yorkshire Hi-Fi Club

Post by Nick »

Well, I have no idea what the as new model measurements would be as I don’t have such a unit on hand. I have not removed the case yet, my plan was the swap the valves between channels and see if the higher distortion and rolled off bass followed the valves.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#349 Re: Yorkshire Hi-Fi Club

Post by Nick »

I also measured the input impedance of the preamp used last week, and its as previously said, 3k (I wanted to check it wasn’t a typo on the web site as all their other preamps have a higher value for the single ended inputs). So a good spot there, and it will certainly affect the valve stages performance.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#350 Re: Yorkshire Hi-Fi Club

Post by Nick »

Modwright frequency response. input set as MM, 1mv input. Same with MC.

Image
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#351 Re: Yorkshire Hi-Fi Club

Post by Nick »

Ok, the droopy response follows the 6n1p, so probably worth getting a couple more and picking the best pair. Nicely built as I remember from repairing Modwright kit in the past. The MC input is handled by three 2sk170's for each chan it seems. I also remember now that they like battery bias so the output stage has a 3.6v lithium cell for each channel. I think that may explain the sonic signature of the unit. Battery bias was always a bit of a Marmite thing.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Ali Tait
Eternally single
Posts: 4374
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#352 Re: Yorkshire Hi-Fi Club

Post by Ali Tait »

The valves were all new NOS Nick, will get some more.

Thanks for taking the time, it’s appreciated. Any thoughts on mods?
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#353 Re: Yorkshire Hi-Fi Club

Post by Nick »

Ali Tait wrote: Sat Jun 02, 2018 7:58 pm The valves were all new NOS Nick, will get some more.

Thanks for taking the time, it’s appreciated. Any thoughts on mods?
I would leave well alone. Its very possible that the distortion I heard at David’s was down to the 3k load from the preamp. I don’t hear it here. Could try and get the RIAA flatter, but I would get the two channels to match first.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
The Stratmangler
Shed dweller
Posts: 2890
Joined: Fri Aug 24, 2007 1:50 pm
Location: Rossendale, Lancashire

#354 Re: Yorkshire Hi-Fi Club

Post by The Stratmangler »

Nick wrote: Sat Jun 02, 2018 8:02 pmIts very possible that the distortion I heard at David’s was down to the 3k load from the preamp
The Soulution preamp used has the built in phono stage?
Chris :happy3:
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#355 Re: Yorkshire Hi-Fi Club

Post by Nick »

No.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
The Stratmangler
Shed dweller
Posts: 2890
Joined: Fri Aug 24, 2007 1:50 pm
Location: Rossendale, Lancashire

#356 Re: Yorkshire Hi-Fi Club

Post by The Stratmangler »

Chris :happy3:
User avatar
Ali Tait
Eternally single
Posts: 4374
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#357 Re: Yorkshire Hi-Fi Club

Post by Ali Tait »

Nick wrote: Sat Jun 02, 2018 8:02 pm
Ali Tait wrote: Sat Jun 02, 2018 7:58 pm The valves were all new NOS Nick, will get some more.

Thanks for taking the time, it’s appreciated. Any thoughts on mods?
I would leave well alone. Its very possible that the distortion I heard at David’s was down to the 3k load from the preamp. I don’t hear it here. Could try and get the RIAA flatter, but I would get the two channels to match first.
Ok thanks Nick.
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#358 Re: Yorkshire Hi-Fi Club

Post by Nick »

The Stratmangler wrote: Sat Jun 02, 2018 8:27 pm
Nick wrote: Sat Jun 02, 2018 8:02 pmIts very possible that the distortion I heard at David’s was down to the 3k load from the preamp
The Soulution preamp used has the built in phono stage?
I stand corrected, its the 520 so it has got the phono stage.

But not sure what bit of "I measured" you were unsure about?
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
The Stratmangler
Shed dweller
Posts: 2890
Joined: Fri Aug 24, 2007 1:50 pm
Location: Rossendale, Lancashire

#359 Re: Yorkshire Hi-Fi Club

Post by The Stratmangler »

Nick wrote: Sat Jun 02, 2018 10:30 pmBut not sure what bit of "I measured" you were unsure about?
Nothing whatsoever.
There's nothing to question about "I measured".

I thought I'd ask, just because of the oddity in the specification in that particular preamp.
3kΩ input impedance is what I'd expect to see on a microphone preamp, not a linestage preamp - the loading is likely to tilt the EQ of line level equipment plugged into it.
Chris :happy3:
User avatar
mainscablesrus
Old Hand
Posts: 638
Joined: Thu Jun 16, 2011 12:13 pm
Location: Huddersfield
Contact:

#360 Re: Yorkshire Hi-Fi Club

Post by mainscablesrus »

Its this baby

https://soulution-audio.com/series5/sou ... amplifier/

Never thought to try the built in phono stage!! Bummer.
You can't change how people treat you or what they say about you. All you can do is change how you react to it.
Mohandas Karamchand Gandhi
Post Reply