PRR-176 REV 4 Build Thread ***Manual up!***1/16/14 - (chk 1st post)

[mrdarwin]

[/quote]

Actually, I'm pretty sure you all can just replace the "1k 2watt" resistors in the power supply with "5k 2 watt" (actually 4K3 seems like a better value after simulating it) resistors and be fine using 240V instead of 120V...I've done the calculations and nothing *should* blow up. Some one try it for me, or correct me if this is a mistake!! That would be A LOT easier for you guys, us 120V can't have all the fun.

Also for reference, it will be about 40ma of current total for the tubes.


[/quote]


Can European DIYers use two toroidal transformers?

 

[e.oelberg]

dear Abe !

could you do us a favour an upload the schematics too. In my case, I'd like to modify the output section and schematcis would be very helpfull.

thank you very much

 

[Esoterimix]

Surprisingly close to done  8) Just need to get a chassis now... Might just DIY one or cannibalize some other piece of gear... @Abe, do the rev4's have any issues with vu's as opposed to mA meters? I know there was some issues in previous revisions... Thanks! Can't wait to get everything I need for the DOA's... Getting closer every day...

 

[mrdarwin]

One question...
Jumpers are only for left channel or do we have to copy 3 jumpers on right channel?
thanx

 

[shot]

Actually, I'm pretty sure you all can just replace the "1k 2watt" resistors in the power supply with "5k 2 watt" (actually 4K3 seems like a better value after simulating it) resistors and be fine using 240V instead of 120V...I've done the calculations and nothing *should* blow up. Some one try it for me, or correct me if this is a mistake!! That would be A LOT easier for you guys, us 120V can't have all the fun.

Does that mean that mains 230V can be connected directly to the PSU board (with fuse of course)?

 

[e.oelberg]

for sure you can, I wouldn't – still to dangerous

 

[abechap024]

Actually, I'm pretty sure you all can just replace the "1k 2watt" resistors in the power supply with "5k 2 watt" (actually 4K3 seems like a better value after simulating it) resistors and be fine using 240V instead of 120V...I've done the calculations and nothing *should* blow up. Some one try it for me, or correct me if this is a mistake!! That would be A LOT easier for you guys, us 120V can't have all the fun.

Does that mean that mains 230V can be connected directly to the PSU board (with fuse of course)?

NO!

You NEED galvanic isolation NEVER, EVER, EVER directly connect the mains to anything besides a transformer or switching power supply.

You just use a dual primary, dual secondary. Connect one of the 2 primary coils to mains and the other primary coil connect to the power supply HV input, change the resistors to 4.3K and you *should* be good to go.

Also, thank you for asking that question. It will hopefully clear it up for anyone else. We want people to be safe

 

[abechap024]

dear Abe !

could you do us a favour an upload the schematics too. In my case, I'd like to modify the output section and schematcis would be very helpfull.

thank you very much

I'll get them up tonight

 

[abechap024]

Surprisingly close to done  8) Just need to get a chassis now... Might just DIY one or cannibalize some other piece of gear... @Abe, do the rev4's have any issues with vu's as opposed to mA meters? I know there was some issues in previous revisions... Thanks! Can't wait to get everything I need for the DOA's... Getting closer every day...

Awesome! I would use VU's with the Rev 4.

I'll upload the BOM for the doas

 

[abechap024]

One question...
Jumpers are only for left channel or do we have to copy 3 jumpers on right channel?
thanx

Only as marked. Its actually 2 on the left channel and 1 on the right channel.

 

[mrdarwin]

Hi
another question:
I would like to build a stereo precision prr176 with stepped switchs instead pots. When stereo link is selected, which parameters are linked? input, output, attack, release? Do I have to build stepped switchs for all 8 pots?
thanx

 

[e.oelberg]

sidechain is linked. you still have to set all other parameters

 

[ding]

Surprisingly close to done  8) Just need to get a chassis now... Might just DIY one or cannibalize some other piece of gear... @Abe, do the rev4's have any issues with vu's as opposed to mA meters? I know there was some issues in previous revisions... Thanks! Can't wait to get everything I need for the DOA's... Getting closer every day...

Awesome! I would use VU's with the Rev 4.

I'll upload the BOM for the doas

Just making sure 1mA meters will still work since these are the ones I originally bought.

 

[abechap024]

sidechain is linked. you still have to set all other parameters

That is correct. You can mod it to where only the left channels controls work when stereo link - thats how all the other revs worked. but this one links both for more versatility. I'll be uploading info on how to do that.

 

[tazwolf]

Hi Abe!
My shipment was damaged , the envelope split so i didn't get any tube pcbs or opamp pcbs, i replied back to the invoice statement from acsound expaining what happened
but no reply so far. Do you have any tube mount pcbs left? i would also like 6 of your discrete opamps because i have already bought the 1U case so mounting from below
is not an option but I am more than happy to pay for  6x doa pcbs and the tube pcbs and shipping, really want to build this. So let me know.

Do any of the transistors on the opamps need to be matched for hfe? if so which ones?

Thanks
/taz

 

[abechap024]

Hi Abe!
My shipment was damaged , the envelope split so i didn't get any tube pcbs or opamp pcbs, i replied back to the invoice statement from acsound expaining what happened
but no reply so far. Do you have any tube mount pcbs left? i would also like 6 of your discrete opamps because i have already bought the 1U case so mounting from below
is not an option but I am more than happy to pay for  6x doa pcbs and the tube pcbs and shipping, really want to build this. So let me know.

Do any of the transistors on the opamps need to be matched for hfe? if so which ones?

Thanks
/taz

Hi Taz,
Sorry I thought we got back to you on that email. Thanks for making the extra effort to get ahold of me. Sometimes emails get lost in the cracks but it is not intentional! Yes I get send you some. Email me again or pm me with your address and what you need.

And on the discrete opamp, you do (can) match the 2 bc550 transistors on the input.

 

[tazwolf]

Hi abe

Should i reply back to the ac sound email address or pm you here on group diy with my details?
not your fault the package split, postal service must have been playing frisbee with it, split right through the
end of the envelope, almost like some one had cut it with a knife.

but i would like 6 opamp pcbs but most importantly the tube pcbs and am more than willing to pay for them as well as shipment.
Let me know the best way to get in contact, you should still have the email from me to acsound but i had not realised i was missing the tube pcbs when i wrote the email.

regards
/TAz

 

[ilfungo]

I'm sorry but I have a big doubt
I compato two toroidal DONAUDIO
specifications:
Primary: 2 x 115v (230v)
Secondarys:
18v 1.2A
18 v 0.4A
120v 50mA

the two secondary (18v)

Which one should I use for the filaments and which for the IC's?
thanks

 

[e.oelberg]

the one with the higher mA for filliament

 

[ilfungo]

sorry
and the other 50mA is sufficient for all the rest?
Thanks