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shunt regulated upgraded ParamourII 45 project starts today

24.22.227.62

I got the components in yesterday for the conversion of my Paramour II with iron upgrade to a 45 amp with shunt regulation for both the driver and the output stage. I'll shoot pictures of the installation process, and if it works as well as we hope I'll take a survey and put together a production run of the conversion kit for iron upgraded Paramour II owners who want to try it. Perhaps PJ will pipe in here about the possibility of using this mod in earlier versions of the iron upgraded Paramour. If I'm not mistaken this would be the only production parafeed SE amp that is fully shunt regulated.

My plan is to try this amp on the ribbon tweeter in my S8s, and to build a separate Paramount for each of the eight woofers. I bet it would be equally useful on the super efficient slot loaded tweeter of the Climax, if not even better.

Follow Ups:

RE: shunt regulated upgraded ParamourII 45 project starts today - sven007 23:26:26 05/25/07 (0)
Please let me know when I can purchase this upgrade kit and schematic. Thanks, Paul
RE: shunt regulated upgraded ParamourII 45 project starts today - ironbut 17:19:30 05/24/07 (0)
Yup, just because I can. ;^)> I'll probably sell off most of the amps after I build them, unless it turns out to be a sound I can't live without.

'ata Boy Doc! Great project.
Go Man, Go!
success - Doc B. 07:17:27 05/24/07 (8)
I got the first SR45 running last night. Tubes were brand new so it needed some break in before I could really judge it. By late last night it was getting into a groove. The 45 type sonics we hoped for are there - the black background and very natural voices. And the cool part is the sucker has bass! I've usually considered the 45 a tweeter amp tube because it always sounds lean to me. But this shunt regulated setup has a bass balance more like our 300B amps, ample (within it's 1.9 watt output capability), extended and quick. Top end is very sweet and extended as we hoped also. Overall the impression is of a very natural, tonally balanced and relaxed sound, low on fatigue and very quick.

This is a conversion of a Paramour II with the MQ iron upgrade kit, so I had one of those playing in the other channel for comparison. There are some differences beyond sonics, like the fact that the SR45 amp is quite a bit less sensitive and has roughly half the power output. But once the levels are matched you can hear a distinct refinement to the sound from the fully regulated amp.

I'll be building and photographing the second amp today. If there is enough interest among upgraded Paramour II owners (like ten of you) I could invest the time to make up a kit. So let me know here if you are interested, and talk a few of your bottlehead buds into trying it too...
- RE: success -yes to the SR45 - awsjr 02:40:42 05/28/07 (0)
  Doc....I have the paramour II with iron upgrade and would be very interested in the SR45 conversion....please let me know the details....thanks -Al
- RE: success - Doc B. 08:06:34 05/25/07 (0)
  Second amp is assembled and ready to check out. After doing inventory this morning it looks like you guys have been buying Paramounts fast enough that there isn't enough iron left from the current production run for my multi-amp experiment. All I can say is - thanks!
  
  I'm pretty sure there's about three kits left. If you guys don't buy them in the next few days I'll build one kit into a pair of shunt regulated Paramount 2A3s.
- what tubes are you using? - xcortes 12:03:50 05/24/07 (3)
  nos or new?
  - RE: what tubes are you using? - Doc B. 14:13:36 05/24/07 (2)
    I ran a Cunningham globe 245 to verify operation and now there is an EML 45 in there. I have had TJs in the past and liked them. Don't seem to have any on hand to try. I suspect they ended up at the studio. Since I'm not seeing a lot of folks opting in for these I will go ahead and put the second one together without spending a lot of time to document for a manual. If folks want to try this I can always supply just a schematic and parts, and say "it's for advanced users".
    - Pleease! - xcortes 15:58:54 05/24/07 (0)
      Too many BH amps and upgrades waiting for the solder iron preclude me from buying a Paramour. I would love, however, to buy the kit if you think it can be retrofited to hombrew Excite amps. Also, if you supply an schematic and parts list I would love to try it.
      
      I assume that in order to do this mod the Excites would need to be RC coupled, right? There's, as always, a compromise between DC coupling vs RC coupling with shunt regulation, I guess.
      
      Well hopefully you will post more details and I'm willing to try it.
      
      BTW Doc, my five Paramounts project just took a turn when I decided to upgrade the iron with TFA-2004 nickels and EXO-003 chokes. We'll see how they stand vs my Parabees with DC heaters and JT Parabee 2 mod! Almost identical amps except for the driver tube?
    - RE: what tubes are you using? - AZ_Gary 15:14:20 05/24/07 (0)
      Doc,
      
      My Paramour II with Iron and Cap Upgrade is and always has been a 45 (Sophias) amp. I would appreciate the schematic and parts plus any tips you want to pass on.
      
      Gary
      
      Vinyl and Film Forever
- I am out 2 weeks ...now you are talking dirty -love it!!!... - Nutube 11:32:29 05/24/07 (0)
  BTW the PARAMounts are very very nice strong and musical for my midbass before the sub takes over...great synergy with my 2A3.
  I am watching you on this 45 trip....... :)
- RE: success - AZ_Gary 07:30:31 05/24/07 (0)
  Count me in.
  
  Gary
  
  Vinyl and Film Forever
RE: shunt regulated PG II - RPMac 06:04:49 05/24/07 (0)
Can shunt regulation for the output stage of Paraglow II work?
Hey Doc, how will you be implementing the crossover? - Mikey 06:42:13 05/23/07 (2)
Active I presume, correct?

Mike
- RE: Hey Doc, how will you be implementing the crossover? - Doc B. 07:37:53 05/23/07 (1)
  Egad man, I'm on the brink of my wildest adventure! Don't bore me with details! ;^)>
  
  I probably will use a line level crossover of some sort, and a preamp with a low output impedance and a s***load of drive (FPIII, anyone?). Rigging up a speaker level crossover for each woofer would be a PITA, plus it would be possible to tweak the filter curve for each driver within each amp, allowing for experimentation with frequency shading. All that said we may end up having to do some correction at the drivers as well. I would put a stepped level control on each amp as well, so that we can easily experiment with amplitude shading as well. I haven't turned PJ loose on this one yet. At some point he will analyze the setup and make a first cut at a crossover design.
  
  Another interesting idea for this project is that we could use Paramounts with the same fully shunt regulated circuit as the shunt reg 45. Instead of a direct coupled 2A3 amp we would build a cap coupled 2A3 amp. This leaves voltage headroom for the shunt regulator. So you are putting about 24W into each array rather than the 64W you would see with 300B Paramounts. You should still be able to hit something like 106dB peaks, and every tube in the signal chain would be shunt regulated.
  
  If I use the slot tweeter version of the S8 instead of the ribbon version, being driven by the 45 amp the slot tweeter should not have much trouble keeping up. The only issue is that the slot tweeter doesn't go as high as the ribbon. However it integrates at the crossover point better. I could put my plasma tweeters on top to add some HF extension, though they can't play very loud (maybe a good thing?). Or some ribbons could be crossed over at some very HF. Might be worth trying, or it might be a mess because of phase problems between the tweeters.
  
  Ooooh, this is going to be fun. Once this one is done I'll get back to my concrete near field monitor project.
  - Yep, that's cool... - Mikey 07:55:45 05/23/07 (0)
    In my experience, whenever you can connect the loudspeaker terminals directly to the amplifier binding posts the clarity and resolution improve immensely!
    
    Not only that, but you're not 'throwing away' any amplifier power like you would with a passive loudspeaker crossover....as I'm sure you already know.
    
    The frequency and amplitude shading possibilities are the icing on the cake!
    
    When are you getting started? Are you done yet? :-)
RE: shunt regulated upgraded ParamourII 45 project starts today - vanofmonks 16:54:04 05/22/07 (6)
I have a question in general. Is it really necessary to burn off the same current in the shunt as the output stage in a Class A SE parafeed stage? For example, for a stage biased at 55ma, with a plate choke, would a ccs to feed the shunt regulator set 75ma work? Or would you need to set it 110ma? I have seen many state that the shunt should shunt the same amount of current as the load, but never a reason why for a class a stage.

Thanks,
Chris
- RE: shunt regulated upgraded ParamourII 45 project starts today - Paul Joppa 20:30:36 05/22/07 (3)
  The "rule of thumb" comes about from series feed power stages, where all of the signal current flows through the power supply. The peak signal current, normally supplied from the last capacitor of the power supply, must then come from the shunt regulator shunting less current - essentially, the output stage and shunt regulator act like a class-A push-pull stage, swapping current back and forth.
  
  For all circuits, the shunt regulator must be able to supply the peak current demanded from the circuit being regulated. In parafeed, the power supply signal currents are small except at the lowest frequencies. For 2 watts output at 30Hz with a 3000 ohm load (the upgrade Paramour output stage) the current through the 40 henry inductor is 14.5mA peak. Assuming this is the worst case, that is the minimum shunt reg current. For driver and preamp circuits, the peak signal current is usually no more than 20% of the quiescent current.
  
  Of course there is always some virtue in operating circuits (such as shunt regulators) with some current overhead. So we don't really know how well this low current reg/parafeed combo will work - hence the experiment. Based on other experiments with shunt regulators over the years, we expect great things - but listening will tell.
  - RE: shunt regulated upgraded ParamourII 45 project starts today - vanofmonks 04:10:23 05/23/07 (2)
    Thanks for the explaination. Would you be so kind as to share the formula for determining the current swing through the choke?
    
    Thanks,
    Chris
    - RE: shunt regulated upgraded ParamourII 45 project starts today - Paul Joppa 10:21:45 05/23/07 (1)
      Sure, but you probably already know them!
      
      Voltage at the plate of the tube comes from:
      
      ** Power equals voltage squared over R
      
      R is the OPT impedance, 3000 ohms in this case. Power is a bit less than two watts, so voltage is the square root of 2*3000 or 77.5 volts. That is RMS voltage, so multiply be 1.414 to get peak plate voltage of 109.5 volts.
      
      Since the plate choke is at constant voltage at the top, and plate voltage below, apply Ohm's law to get the current in the choke:
      
      Current equals voltage over impedance
      
      Impedance is the inductive reactance, 2 * pi * frequency * inductance. The BH-6 plate choke is 40 henries, so at 30Hz this is 7540 ohms, and peak current is 109.5/7540 or 14.5mA.
      - RE: shunt regulated upgraded ParamourII 45 project starts today - vanofmonks 19:04:57 05/23/07 (0)
        
        In Reply to: RE: shunt regulated upgraded ParamourII 45 project starts today posted by Paul Joppa on May 23, 2007 at 10:21:45
        
        Thanks again. You were right, I did know them. It helps to know how exactly to apply them though.
        
        Chris
- RE: shunt regulated upgraded ParamourII 45 project starts today - Doc B. 17:35:53 05/22/07 (1)
  That idea of equal current levels is just a rule of thumb. We are shunting what is left of the available power transformer current capacity beyond what the driver and output stages draw, about 13 mA. The 45 is drawing about 36 mA and the driver a little under 4mA. And of course there is a C4S feeding the shunt reg and the driver and the output stages, and a C4S loading the driver stage as in the stock ParamourII. So there is a little more current drawn by the bias circuits for those active loads.
  - Got it, Thanks Doc.(nt) - vanofmonks 18:19:09 05/22/07 (0)
    .
What are the operating points - xcortes 15:23:53 05/22/07 (1)
What are the operating points of the Paramour under the 45 configuration? And also what's the MQ upgrade OPT primary impedance?

Oh, and cool project!
- RE: What are the operating points - Paul Joppa 10:27:37 05/23/07 (0)
  Regulated voltage is 320 volts; the currents and impedances are answered elsewhere in this thread. However, note that this is the first cut and currents especially may change.
a separate Paramount for each of the eight woofers - Caddis 13:40:26 05/22/07 (6)
What? A total of 18 amplifiers for a stereo setup?
- RE: a separate Paramount for each of the eight woofers - Doc B. 14:28:08 05/22/07 (5)
  Yup, just because I can. ;^)> I'll probably sell off most of the amps after I build them, unless it turns out to be a sound I can't live without. With the slot tweeter version of the S8s I should be able to hit about 108dB peaks throughout most of the speaker's range. With the ribbon tweeter version of the S8 the 45 amp amp will set the limit, somewhat. However we have found that you really don't need much power above 2kHz.
  - I smell an investment opportunity... - tonyb_2k 16:47:31 05/22/07 (2)
    I want to know who Doc's power company is; I have some funds that need investing.
    - RE: I smell an investment opportunity... - sunseeker 16:55:57 05/22/07 (1)
      Hydro, clean power, I love it.
      - RE: I smell an investment opportunity... - Doc B. 17:39:58 05/22/07 (0)
        
        In Reply to: RE: I smell an investment opportunity... posted by sunseeker on May 22, 2007 at 16:55:57
        
        "Hydro, clean power, I love it."
  - Are you thinking Doc might be going a liitle over the top? - Ian L 15:22:28 05/22/07 (1)
    Well, think again. . . .
    - and another one (Open in New Window)
    - and people wonder what's causing global warming... - caffeinator 10:18:48 05/23/07 (0)
      it's all those amplifiers!

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