I've just got hold of a gutted 32.5 , mother board only and the case. Now I intend to use Avondale 821 boards and a single input (CD) I'll fit phonos to the holes where the BNC's were, one pair for the input and one pair for the output. I'm going to ignore the selector switch ,the mono switch and the tape monitor switch. Is it OK to wire the input direct to the volume pot (50K Noble) , without using resistors inplace of the balance pot , then run the volume pot direct to the 821 boards , the 821's will be dual railed running off a TPX1 , then the output fed straight to the phono outs. All 0volts will go direct to the star erth point....cheers ...Jon
gutted 32.5 for single input
- Thread starter zener
- Start date
Jon,
Yes, din socket to vol pot input, vol pot output to 821 input, 821 output to output din. If you like, you could just tack the wires onto the back of the board, this is no bad thing, the motherboard is quite lossy.
Make sure to common the 0V between the boards, solder no connection more than two wires thick (IMPORTANT: try starring the 0V together but only touching in a small area, in other words, definately no big solder clumps)
Yes, din socket to vol pot input, vol pot output to 821 input, 821 output to output din. If you like, you could just tack the wires onto the back of the board, this is no bad thing, the motherboard is quite lossy.
Make sure to common the 0V between the boards, solder no connection more than two wires thick (IMPORTANT: try starring the 0V together but only touching in a small area, in other words, definately no big solder clumps)
Locked myself in the spare room for a couple of hours
The bits
http://i141.photobucket.com/albums/r51/fluffvogel/100_0218.jpg
the almost finised item, just the 5 pin DIN for power and the case earth to instal
http://i141.photobucket.com/albums/r51/fluffvogel/100_0220.jpg
Only one input , no switching , straight to the volume pot and then to the 821 then output , so simple.
Thanks to Mr Tibbs and also Les W ...Jon
The bits
http://i141.photobucket.com/albums/r51/fluffvogel/100_0218.jpg
the almost finised item, just the 5 pin DIN for power and the case earth to instal
http://i141.photobucket.com/albums/r51/fluffvogel/100_0220.jpg
Only one input , no switching , straight to the volume pot and then to the 821 then output , so simple.
Thanks to Mr Tibbs and also Les W ...Jon
Its up and running , works fine for something that was destined for the dust bin. I'd say what I'm hearing is.... what the 821 boards, a Noble pot and a bit of silver wire sound like , it sounds very very good for something that cost the price of £125 (821's) and about two hours work. I now have a pre amp for my Vintage tuner. 
Thanks Markt
and Markf , would i ever throw anything like that away , Its my job to keep these things going along with other DIY enthusiasts.
Oh I forgot to add .......now I've had a good chance to listen , its bloody good and not far behind a GRAD1 ..so a (insert your favourite expensive pre-amp here) ..beater ...hee heee ...bound to be really considering there are no compromises to facilities and sources.
and Markf , would i ever throw anything like that away , Its my job to keep these things going
along with other DIY enthusiasts.Oh I forgot to add .......now I've had a good chance to listen , its bloody good and not far behind a GRAD1 ..so a (insert your favourite expensive pre-amp here) ..beater ...hee heee ...bound to be really considering there are no compromises to facilities and sources.
mark, is this not the sort of you could try and let us know the results. As I have noticed that almost every post of yours seems to be on the same topic. Perhaps it would not be suitable for you though as we don't know what kit you run or where you are based.
It would help us if we knew if you were interested in buying or merely an intellectual excercise.
It would help us if we knew if you were interested in buying or merely an intellectual excercise.
Hi Rex,
I’m not sure that I know what kit you use and where you are based, does it matter?
Can you clarify just who the “us” and “we” are in your statement:-
“It would help us if we knew if you were interested in buying or merely an intellectual exercise.”
What do you want to sell to me?
Did you read Zener’s reply above ,I wonder, if you were in the hi-fi trade, would you give that man a salesman’s job talking gibberish like that.
To answer your question , it was an intellectual exercise ,although I am reluctant to give it that much credence more of an idle thought really but good to hear from you again, post more often Rex.
I’m not sure that I know what kit you use and where you are based, does it matter?
Can you clarify just who the “us” and “we” are in your statement:-
“It would help us if we knew if you were interested in buying or merely an intellectual exercise.”
What do you want to sell to me?
Did you read Zener’s reply above ,I wonder, if you were in the hi-fi trade, would you give that man a salesman’s job talking gibberish like that.
To answer your question , it was an intellectual exercise ,although I am reluctant to give it that much credence more of an idle thought really but good to hear from you again, post more often Rex.
you have a PM , explaining my situation.
As for the rebuild of a dead bit of kit , its for a tuner only based system , that I intend to instal in my spare room , I was given the parts , so the job was done. It sounds very very good and will be very suitable for what its intended for , I would suggest others should try it.
As for giving it credance , Markf , I suppose you have a vested interest elsewhere that would not allow you to believe something home built can possibly sound any good. Well I can think of at least one pre-amp its much better than , namely the doner unit , but then the doner unit would be better if you stripped out all those contacts , switches etc. All production HiFi is a compromise , user facilities being one of them , strip out the compromise and you have a better bit of kit.
As for the rebuild of a dead bit of kit , its for a tuner only based system , that I intend to instal in my spare room , I was given the parts , so the job was done. It sounds very very good and will be very suitable for what its intended for , I would suggest others should try it.
As for giving it credance , Markf , I suppose you have a vested interest elsewhere that would not allow you to believe something home built can possibly sound any good. Well I can think of at least one pre-amp its much better than , namely the doner unit , but then the doner unit would be better if you stripped out all those contacts , switches etc. All production HiFi is a compromise , user facilities being one of them , strip out the compromise and you have a better bit of kit.
Zener,
if "its bloody good and not far behind a GRAD1" then it might be reasonable to expect that with the audiophile 821 boards it will be closer if not equal or even better than the GRAD1 , as you have said, "no compromises to facilities and sources" so really for someone contemplating buying a GRAD1 they could consider your DIY route first and pocket the difference in price approx. 1000UKP.
The real question is would you be prepared to do that Dem., a straight audiophile 821 pre versus the GRAD1 do you not think people would be interested in that?
if "its bloody good and not far behind a GRAD1" then it might be reasonable to expect that with the audiophile 821 boards it will be closer if not equal or even better than the GRAD1 , as you have said, "no compromises to facilities and sources" so really for someone contemplating buying a GRAD1 they could consider your DIY route first and pocket the difference in price approx. 1000UKP.
The real question is would you be prepared to do that Dem., a straight audiophile 821 pre versus the GRAD1 do you not think people would be interested in that?
spent most of the morning listening to the 821 pre amp and about 30 mins this evening. Sounds good and getting better. I've arranged to lend it to a friend who will compare it to a well known pre amp with the no. 5 in its name , should be interesting , I will refrain from any comment about the outcome. I havent compared it to my GRAD1 yet as I've been too busy , that wil be in a couple of weeks time when I have a weekend free.
“This botched together pre-amp is good , but its no GRAD1.”
Zener,
That’s the answer I was expecting to hear. If you think about it ,it wouldn’t be fare
on customers who bought the GRAD1 if you could make a pre amp just as good using the
821 boards. And the audiophile version? again close but no cigar?
Zener,
That’s the answer I was expecting to hear. If you think about it ,it wouldn’t be fare
on customers who bought the GRAD1 if you could make a pre amp just as good using the
821 boards. And the audiophile version? again close but no cigar?
Intending doing this to mine. Last night I split the 24v rails coming from the power supply to feed the individual 821's. I ran a wire from the second 24v pin on the 5 pin DIN plug (I desoldered the one that was there, losing the light on the front of the preamp, but who cares) straight to the +ve connector on the second 821.
I was kind of disappointed at the result. I didn't really hear much difference, if any. Others have written here how it makes a huge difference. However, now I've decided to take out the motherboard altogether and just have the volume pot and the 821's. Not sure about two things though. The appropriate gauge for the signal and power wires and what to do with the grounds since I will be losing the star grounding point on the motherboard.
Any advice would be appreciated.
Colin
I was kind of disappointed at the result. I didn't really hear much difference, if any. Others have written here how it makes a huge difference. However, now I've decided to take out the motherboard altogether and just have the volume pot and the 821's. Not sure about two things though. The appropriate gauge for the signal and power wires and what to do with the grounds since I will be losing the star grounding point on the motherboard.
Any advice would be appreciated.
Colin