Search found 374 matches

by PeteC
Sat May 18, 2013 5:22 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

.....Finished..... and beautiful to record with - very much recommend this as a recording preamp for anyone into diy recording. Forgive the poor quality of the hasty iphone pic. http://i55.photobucket.com/albums/g159/pedrocortez/14A788D1-3582-4B55-846B-83A61BD5740C-1107-00000104A6169E5E_zps2b1427db....
by PeteC
Sat May 18, 2013 5:18 pm
Forum: Everyones Projects
Topic: 6EM7 into EL34 ?
Replies: 18
Views: 13030

6EM7 into EL34 ?

Hi all, my main amp for last 2 years has been the 6EM7 into 300B. http://www.audiodesignguide.com/my/new300bxls2004/new300bxls.html Now pretty much the last pair of 300B's has packed in this week ( well one of the pair and I'm left with one lone EH300B ) - I've had bad experience of both EH 300B's a...
by PeteC
Thu May 16, 2013 10:20 pm
Forum: Everyones Projects
Topic: It is about time I built a push pull amplifier
Replies: 171
Views: 44710

Ed, I have just finished a dual channel mic pre with Phantom power. I used Ian Bell's simple phantom circuit off GroupDiy. Worth a go perhaps. I have a couple of Ian's phantom pcbs to use in future projects but built the current used circuit on perfboard and its works fine. It runs off a 2x25v toroi...
by PeteC
Thu May 16, 2013 11:49 am
Forum: Buying and Selling
Topic: TJ Meshplate PX25 - Pair
Replies: 2
Views: 1847

I have returned PM Paul

cheers
Pete
by PeteC
Wed May 15, 2013 10:38 pm
Forum: Buying and Selling
Topic: TJ Meshplate PX25 - Pair
Replies: 2
Views: 1847

TJ Meshplate PX25 - Pair

Hi all, I have a pair of lovely TJ Meshplate PX25s that I bought from Steve on this forum a couple of years ago, and I haven't been able to use them at all so far ( other studio projects taking all my time ) For sale for £60 the pair for collection from Leeds. ( Or post to cover costs, delivered con...
by PeteC
Tue Apr 30, 2013 9:36 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

Hi All, some progress on the dual REDD mic preamp for those that are interested in the muso studio side of things.....its all valves at the end of the day. http://i55.photobucket.com/albums/g159/pedrocortez/46645D56-B8C0-474A-B752-73382214EB31-417-0000003D6FF71E2A_zpscad7c7aa.jpg http://i55.photobuc...
by PeteC
Mon Apr 15, 2013 10:26 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

thanks Mike,
good idea - I will try that.

Rgds
Pete
by PeteC
Sun Apr 14, 2013 5:16 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

Many thanks again Mike , yes its the exact RED447 circuit. yes - I caught the 82K and reasoned that it needed to be 8.2K for the anode. I have 1K grid stoppers on the E88CC right at the pins, but have my plate and grid wires running from the tagboard about 1-1.5" long. Perhaps I should try scre...
by PeteC
Sat Apr 13, 2013 3:13 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

so perhaps grid stopper on the EF86 might be a good idea ?

Anything else worth doing to tame the RF ?

just tested my gain in dB with sig gen and all looking right vs the original EMI amplifier , so thats encouraging. 37, 43, and 47dB gain settings .

Cheers
Pete
by PeteC
Sat Apr 13, 2013 1:37 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

Thanks Mike that's really helpful - I hadn't considered that at all ! I may stick with the 390K screen R for now. Do you have any experience of of seeing voltages change in input circuits when the chassis is additionally earthed from the signal ground - even if the chassis inst electrically connecte...
by PeteC
Fri Apr 12, 2013 7:47 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

OK thanks Mike, I think I will play with a variable resistor in the srceen circuit and see what value gives a slightly lower screen and slightly increased plate voltage. I'm getting 108v across 390K - so about 0.3ma screen grid current which seems reasonable - maybe it was meant to be this way - but...
by PeteC
Fri Apr 12, 2013 4:49 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

At the moment I have around 24v higher on the screen than the plate.

Rgds
Pete
by PeteC
Thu Apr 11, 2013 10:17 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

thanks Phil - that was fast ! That's what I'm thinking too - based on fact that 0.3ma seems to be running through the screen grid and the 390K screen resistor - I'm assuming there will be a voltage drop of about 0.3ma x 390K = 117v vs the Ht which is at 205v . So a screen voltage of around 205-117 =...
by PeteC
Thu Apr 11, 2013 9:58 pm
Forum: Everyones Projects
Topic: REDD47 - Legendary Abbey Road preamp build - question !
Replies: 17
Views: 12149

REDD47 - Legendary Abbey Road preamp build - question !

Hi all, I have been building 2 channels of point to point microphone preamps for my little recording studio following the renowned REDD47 circuit used at Abbey Road on many, many Beatles recordings. Here's a link to a doc with the schematic which some of you will find interesting for its own sake as...
by PeteC
Thu Apr 11, 2013 7:47 pm
Forum: Buying and Selling
Topic: WTB - 2x High Quality EF86 or EF806's
Replies: 2
Views: 2451

Hi Steve, At the moment a couple of unbranded "Made in Russia" EF86's that came out of an old RadioVox PA chassis that I picked up second hand to convert to guitar amp. Thats all done , but I still had these EF86s in my stash. I thought I ought to try some different valves as the preamps I...