Hey peoples,
Anyone know much about this pre amp? I aquired it not long ago and cant find any info at all on the web about it.
Its a fantastic preamp mind, dont use the phono stage as i have a heavy modified CA 640p which i use instead (from details posted on here).
Tx muchly!
Anyone know much about this pre amp? I aquired it not long ago and cant find any info at all on the web about it.
Its a fantastic preamp mind, dont use the phono stage as i have a heavy modified CA 640p which i use instead (from details posted on here).
Tx muchly!
Yes, read that not long ago.. cant find much for this particular preamp though.
Im trying to work out what the circuit layout is and also what opamps are used, so i can do some upgrading to maybe discreate versions but cant find nothing!
All the opamps in the preamp seem to have heatsinks glued onto them, which is making it rather hard to see what they are. Also ive noticed every resistor in it is holco.
Im trying to work out what the circuit layout is and also what opamps are used, so i can do some upgrading to maybe discreate versions but cant find nothing!
All the opamps in the preamp seem to have heatsinks glued onto them, which is making it rather hard to see what they are. Also ive noticed every resistor in it is holco.
Have you considered contacting Tom Evans Audio Design directly and enquiring whether Tom would be interested in assisting you?
Many audio designers will answer an e-mail that they consider interesting.
Yes, unfortunately before i posted here i sent him an e-mail asking about the preamp and whether he has any info on it, or remember what components he used.
Im still waiting for an e-mail back 🙁
Im still waiting for an e-mail back 🙁
Ive found yesterday 2 JFET opamps which i think power the phono stage. Cant see any circuit layout at all on the board and maybe will need to resort to testing with a multimeter for continuity between components to work out a circuit.
Here is a link to the patent filed in the EC days:
espacenet - Bibliographic data
The Finestra may, or may not, use this circuit.
In his later designs (Michell ISO, Argo, the TEAD stuff), Evans used
an opamp-wrapped-around-opamp trick that came from an application note: Analog Devices AN-107 (James Wong).
espacenet - Bibliographic data
The Finestra may, or may not, use this circuit.
In his later designs (Michell ISO, Argo, the TEAD stuff), Evans used
an opamp-wrapped-around-opamp trick that came from an application note: Analog Devices AN-107 (James Wong).
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It does look like it may apply, as the main layout is 2x 8pin opamp, followed by a 16pin chip (maybe quad opamp?, no writing on it) and then followed by another 2 opamps.
An externally hosted image should be here but it was not working when we last tested it.
This is the basic layout from what i can see. I dont believe any components are under the board.
It seems to be a pretty stable layout, so i reckon maybe LM4562HA for first 2, and also LM4562HA on browndog quad adapter. Then to finish 2 Newclass D duals for final opamps and maybe phonostage.
Well during testing pinouts for the chips (confirmed 4 dual opamps and 1 quad opamp) i realised that the supply rails were slightly out (+16.28v...0v...-15.75v). Can anyone think of a reason for this offset other than just the age? I set the pots in the PSU section so i now have +16.00v....0v....-16.00v and its made a big difference to the soundstage and overall depth of the sound. I dont think this would have been set manually to have this offset as i cant think of a reason why... what do you guys reckon?
Just an update on this... ive replaced most of the opamps with single LT1028 and 2x LT1028 on browndogg adapters where dual opamps were placed. The sound is much better than before, much more defined vocal and massive soundstage. Also i replaced the quad in the middle with 2x4562 SOIC on browndogg adapter.
Only issue is massive oscillation on the LT1028 which hopefully i will fix with 33pf between pins 5 and 6 tomorrow and also 0.1uf wima between + & - Pins.
Only issue is massive oscillation on the LT1028 which hopefully i will fix with 33pf between pins 5 and 6 tomorrow and also 0.1uf wima between + & - Pins.
Hey guys, just a quick one.
Seems ive managed to get the opamps stable (not hot anymore anyways, just warm to touch after 12hrs burn in). However my scope is giving me a strange reading of a sine wave.
I dont have a picture on me to show, but basically its a nicely formed sinewave of 60hz going into the opamp, but coming out looks very bloated. The structure of it is still good and no clipping has occured, but seems to be alot fatter of a wave form compared to the original.
Seems ive managed to get the opamps stable (not hot anymore anyways, just warm to touch after 12hrs burn in). However my scope is giving me a strange reading of a sine wave.
I dont have a picture on me to show, but basically its a nicely formed sinewave of 60hz going into the opamp, but coming out looks very bloated. The structure of it is still good and no clipping has occured, but seems to be alot fatter of a wave form compared to the original.
Finestra Pre Amp
I have a Finestra. Finest Pre amp. short of daft money. shame you don't use the phono as it is very good indeed. Tom Evans phono amps retail for £4k++
bought my Finestra from Nick - HiFi Emporium UK he is an absolute encyclopeadia on vintage hifi. known him for years. if you need info / spares etc go to - Hi Fi Emporium Hall Road, Ellingham West, Nr Bungay, Norfolk, NR35 2EN UK
Telephone Nick on: 0044 1508 518468
Email: admin@emporiumhifi.com Facebook: Emporiumhifi Twitter: @emporiumhifi
Happy listening. Telesis.
I have a Finestra. Finest Pre amp. short of daft money. shame you don't use the phono as it is very good indeed. Tom Evans phono amps retail for £4k++
bought my Finestra from Nick - HiFi Emporium UK he is an absolute encyclopeadia on vintage hifi. known him for years. if you need info / spares etc go to - Hi Fi Emporium Hall Road, Ellingham West, Nr Bungay, Norfolk, NR35 2EN UK
Telephone Nick on: 0044 1508 518468
Email: admin@emporiumhifi.com Facebook: Emporiumhifi Twitter: @emporiumhifi
Happy listening. Telesis.