My DIY Pre/phono Pre/Active XO/tube buffer

ben62670

It is kinda a kit. You get some bare boards, a transformer, remote, and a case. The case has just the holes for putting the case together so I had to do some drilling. The relay board is not attached yet. I also upgraded the caps. The pre uses 3 12au7's in it.
Thanks for the compliment.
Ben

engtaz

Looks great Ben.

heiney9

Nice looking piece of gear Ben. What tubes are you running?

H9

hearingimpared

Sounds good over the phone with your turntable!:D

ben62670

heiney9 wrote: »

Nice looking piece of gear Ben. What tubes are you running?

H9

Right now some Chinese 12AU7's. I will upgrade them for the customer before I send it out. I need knobs and stand offs too.
Ben

hearingimpared

I want one!!!!

heiney9

What kind of cost ball park? Why is the tranny so close to the input/output board? Shouldn't it be as far away as possible?

Those Auricaps are very sweet sounding caps.

H9

ben62670

The actual transformer is next to the power supply part of the pre. It is set up to have maximum space to add a phono stage, or a DAC at a later date. The thing is dead quiet.

ben62670

This one is mine. I had to drill and cut all the holes on this one.

Regulated PS with DC heaters.

There are 3 inputs plus separate inputs for MM/MC


I need to touch up near the IEC hole. This thing isn't done yet so there are a few loose boards.

Big Dawg

Very nice. I've been contemplating building a tubes4hifi pre. Can you share where you got the "kit?"

Toolfan66

WOW!!! Looks great Ben. Both of them that is. That is a bunch of holes.

engtaz

Very very nice Ben. Congrats on a job well done. Hope your doing well.

FTGV

Nice work Ben.You even have room left over for one of these.

Face

Looks like a DAC.

zingo

Dac.

punk-roc

looks super good Ben. Strong work!

Jason

TECHNOKID

ben62670 wrote: »

Here is a Pre I built for a Polkie.

Great job Ben! You've been at it for a long time now, you've got to push some out to recoupe some $$$. You've mentioned 60 hours work at one point, how many more hours have you added since? Now that the worse is done (implementing, rearranging and testing) how many hours would you figure it need to put one up? If you intend to sell them, labor is the most expensive part of the project and nobody works for peanuts! That might put a hefty price tag on the units, have you tought of the possibility of selling kits with detailed instructions for the DIYers? That could chop the price tag substantially and allow you to make a few bucks without going into extensive labor on your part... Just food for tought....

Cheers!
TK

ben62670

Hey Fred. Yes I do have room for a DAC in there, and here it is.
http://cgi.ebay.com/High-Grade-24bit-192khz-DAC-fully-assembled-kits-/120551270004?pt=LH_DefaultDomain_0&hash=item1c116a6674#ht_7884wt_822
I have been looking at a solution for playing Flac and MP3's on my system, but none of the players have all the features I wanted. A puter in another room will become the source and a coax will run the digital to the DAC in my Pre.

FTGV

Cool,I bet youll like it and it's tweak friendly.When you get it check the schamatic to verify the cap and res. values in the low pass filter section.I have the old version shown in the bottom pics in your link and as you can see in the pic I posted in post #108 I have changed a number of parts in the LPF.This because the stock values used caused the high frequency roll off to start well below 20k.Replacing the surface mount parts with standard hole through types was a bit of a challenge.

ben62670

I am sure I will like it. The price is silly low for what you get. I'll share the schematic with you if it comes with one. I plan on tubing it with a switch to choose between SS and tubed. I really liked the DAC I got from you, but it is just too big to fit in my case.
Take care and Merry Christmas.
Ben

Toolfan66

So where did you get that heavy duty powder coated aluminum box to build that pre?? :biggrin::cool:

FTGV

Mine came with a schem. so yours should as well.I know that BB eval.board is good but bulky.I look forward to yoUr impressions.


Merry Christmas to you and yours.

FT

ben62670

From one of the most handsome men here on CP:eek: We need to talk about those tanks soon!
Cheers
Ben

ben62670

FTGV wrote: »

Mine came with a schem. so yours should as well.I know that BB eval.board is good but bulky.I look forward to yoUr impressions.


Merry Christmas to you and yours.

FT

I am thinking about using the BB board for some proto work on some different tube setups. There is plenty of real-estate for experimentation. When I am done I may put it all in a case and sell it as a standalone DAC.

Toolfan66

ben62670 wrote: »

From one of the most handsome men here on CP:eek: We need to talk about those tanks soon!
Cheers
Ben

We will I just need some time to get some things caught up at work. We just got the new laser up and running and had a few problems with one of the other ones. They have kept my hands full..

ben62670

Well here I go. Santa dropped by the post office with a package for me
The boards are very small which will make it a little harder for me to mod, but I have good directions for this specific DAC.

ben62670

This is a pia. All the caps are surface mounts. The pic of the middle board is actually larger than real life. This mod is really screaming tube. Another member was asking about how the project was going, and I wanted to first try it SS with some cap mods, but I think I will stick with stock parts for the first test. I do have a low voltage tube buffer that I think would fit the bill for this tube job. I shall be running it fairly soon. BTW the OpAmps are AD827's. I am not familiar with these.
Cheers
Ben

Edit:What Opamp do you recomend here. The voltage is 12-0-12

ben62670

Well I got some caps(6) in there for the OpAmps.

ben62670

Well I have it together now. It is resting on my circuit board(get circuit board(MDF(ya I'm retarded))) and running now. At first it sound awful! I was ready to take all the caps off it and see if I messed up somewhere. It smoothed out in about 5 minutes. I have no idea why it sounded so bad. Another thing is this is putting out more than 2vrms on the analog outs. I know that is not a digital cable. I will make one tomorrow. For now I will let it burn in all night. I have some OPA2134's here too. I may swap them in if I don't like the AD627's. Even though it is fresh out the box it is sounding pretty good. I'll post some more tomorrow. Oh yeh the tubes are doing nothing for now. They were just on my test board.
Ben

ben62670

Well I am very pleased now that things have settled. I had my DAC hooked up to my Modded Denon 2900 and it was amazing how close the sonic signatures were. I would give the nod(just by a hair)to the DAC. If the Denon wasn't used for SACD I would use it as a transport and would have skipped the mods. I have my PC hooked up to it now. I made a custom cable out of RG6 copper shielded cable. I have no complaints about the 40' cable. I have music ripped to FLAC and WMA lossless. I will do some more serious comparo's latter. While I was at it I also made a composite cable the same length so I could use my media center to the fullest. There is a TV/FM tuner card in there too so I can use it as a dvr. The digital out is sent at resolutions up to 192:biggrin: and my DAC connects at that speed:biggrin::biggrin: I hope to have all my Cd's ripped to my hard drive soon. With the large data cache of a puter I feel it is a better transport than most low to mid level CDP's. Also my machine does HDCD. I don't have any so I don't know how well it works. I look forward to downloading some HiRez media soon. The good $hit. 24/96 and better! BTW the imaging is great via puter DAC/2 channel system.
Thanks guys for all your help and advice. I almost dropped some coin on WDTV media player(western Digital(the most formats of all the players and wireless capable)). Glad I didn't Win7 has a great media center.
Cheers
Ben

Edit: I am still thinking tubes for the DAC