I stuck the RIAA EQ in my PAS Phono stage back on the board when I rebuilt it. But it is still in the feedback of the circuit. It will still wander with tube age.
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Bottlehead vs. Dynaco Pas 3
- Thread starter bluepoint123
- Start date
JonL
Lunatic Member
I did those mods on my PAS-3x and thought it sounded different but not better. I actually fooled with the capacitor values on my own to try to tame the shrillness I was getting. I wound up with very close to the stock circuit values, but basically removed from the selector switch.
Geek
Nerd
Hi,
Make sure *everything* is matched... tubes, caps, resistors... everything and it just might work
Cheers!
Make sure *everything* is matched... tubes, caps, resistors... everything and it just might work
Cheers!
To the OP, keep your Pas and wrench it up, they rock!
This is mine---- now if I can figure out how to squeeze another board in there,, hmmm:scratch2:
http://www.audiokarma.org/forums/showthread.php?t=234673
Geek, I understand about the matching. I like that Norman set up, and as I said been droolin on the idea of a Hagerman Trumpet.
The thing I think the Pas lacks is the <super>dynamics, I kinda think it does most everything else within reason. When you start introducing the third stages is wbhen it opens up, well see.
This is mine---- now if I can figure out how to squeeze another board in there,, hmmm:scratch2:
http://www.audiokarma.org/forums/showthread.php?t=234673
Geek, I understand about the matching. I like that Norman set up, and as I said been droolin on the idea of a Hagerman Trumpet.
The thing I think the Pas lacks is the <super>dynamics, I kinda think it does most everything else within reason. When you start introducing the third stages is wbhen it opens up, well see.
Here you go, Kirk. Let me know if you need any at different angles or want a description of where a particular wire goes.
Best wishes,
Bruce
Bruce,
Thanks again for the close ups ...I finally changed my wiring to match yours and its working great!..I can't believe the difference....My volume pot now operates normally, 11:00 is quite loud... I'm curious though my balance pot is rated only 50k and I see yours is rated 100k...wonder why or if it makes a difference.
I'm going to carry on with my comparisons and will post my thoughts soon.
Cheers,
Kirk
wajobu
Boing Boom Tschak
I cannot comment on the Dynaco, but I built a Seduction with the C4S upgrade and stock tubes and it sounds just wonderful. I'm currently using a Grado Gold MM cartridge and plan on trying a high output MC shortly (after speaking with Doc Bottlehead!). The Seduction is dead-quiet and transparent.
The first thing I listened to was a second issue Stereo LP of the Brubeck Quartet's Time Out and it sounded splendid (like the musicians were in the room with me). I can't wait to try an alternate cartridge and TT that I have been working on. Like the Dynacos, there are other modifications that I have been encouraged to try, but I wanted to start dead-stock to trouble-shoot problems with my "build" last summer. I'm using a tubed preamp with no tone controls (Manley Shrimp).
The first thing I listened to was a second issue Stereo LP of the Brubeck Quartet's Time Out and it sounded splendid (like the musicians were in the room with me). I can't wait to try an alternate cartridge and TT that I have been working on. Like the Dynacos, there are other modifications that I have been encouraged to try, but I wanted to start dead-stock to trouble-shoot problems with my "build" last summer. I'm using a tubed preamp with no tone controls (Manley Shrimp).
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MaggieMaggie
Active Member
In case anyone stumbles in here, I had a Foreplay with c4s, then rebuilt it into a Transcendent grounded grid which was a step up, sold that when I got the Audio Research LS16 ( I miss you ). Now I have a 3 with tone controls bypassed and very good 1.0uf coupling caps on the output. Bottlehead is like 2 steps down from this. If you are looking at modern BH, that I haven't heard. You need to add a 1/4 fuse between the switch and power transformer or there will be weeping a wailing when you find out the transformer is almost utterly unobtainable. Triode hasn't had them in years.
trainbuffton
Active Member
My experience was that putting in new boards from tubes for hifi destroyed the bass response of the preamp.
Nothing i could do would bring it back and I eventually sold the unit.
I listen to reggae so bass is very important. I just couldn't do it.
The sound was exceptionally clean but without a good accurate bass response I lose interest.
I ended up building my own preamp based on the HH Scott phonostage and it's end game level gear for me.
Nothing i could do would bring it back and I eventually sold the unit.
I listen to reggae so bass is very important. I just couldn't do it.
The sound was exceptionally clean but without a good accurate bass response I lose interest.
I ended up building my own preamp based on the HH Scott phonostage and it's end game level gear for me.
old thread but I see mention of the RIAA "problems". I'll refer anyone who cares to read further to here for a lot more info.
down a bit on the left side is an article about the PAS phono and another about the PAS line stage in stock properly-functional form. The phono one gets into the supposed problem and correction along with both modeled and actually-measured results that refute it. TL;DR, the stock phono stage is pretty decent as-designed.
I put mine back to the stock phono stage, with the exception of mounting the parts directly to the board and getting them out of the switch. I'm never going to use tape head or the non-EQ mic input options.
Line stage is pretty similar to a Bottlehead Foreplay now, 12au7 per-channel, 1/2 gain, 1/2 cathode follower.
Audio Regenesis resources for Dynaco tube amplifier articles upgrades ST-70 PAS 2-3 ST-35 SCA-35 EFB
Dynaco vintage tube ampllifier technical articles, upgrade, restoration and repair resources for ST-70, PAS, SCA-35, ST-35
www.audioregenesis.com
down a bit on the left side is an article about the PAS phono and another about the PAS line stage in stock properly-functional form. The phono one gets into the supposed problem and correction along with both modeled and actually-measured results that refute it. TL;DR, the stock phono stage is pretty decent as-designed.
I put mine back to the stock phono stage, with the exception of mounting the parts directly to the board and getting them out of the switch. I'm never going to use tape head or the non-EQ mic input options.
Line stage is pretty similar to a Bottlehead Foreplay now, 12au7 per-channel, 1/2 gain, 1/2 cathode follower.