1. Paramour: Top Level Link.
             10% Distortion Tables vs Frequency. Output impedance vs Frequency.

2. Paramour: Stock Output Transformer, Stock  Choke, AVVT 2A3 M tubes,
             Right Amp, 10% distortion pictures, No distortion curves.
             This link opens a new window so you can compare it to other pages.

3. Paramour: Stock Output Transformer, EXO-04 Choke, AVVT 2A3 M tubes,
             Right Amp, 10% distortion pictures, distortion curves.

4. Paramour: Stock Output Transformer, Stock  Choke, Sino 2A3 tubes,
             Left Amp,  10% distortion pictures, distortion curves and pictures.

5. Paramour: Stock Output Transformer, Stock  Choke, AVVT 2A3 tubes,
             Left Amp,  10% distortion pictures, distortion curves.

6. Paramour: EXO-45-VS Output Transformer, Stock Choke, AVVT 2A3 tubes,
             Left Amp,  10% distortion pictures, distortion curves, distortion curve comparison.

7. Paramour: EXO-45-VS Output Transformer, EXO-04 Choke, AVVT 2A3 tubes
             Right Amp,  10% distortion pictures, distortion curves, distortion curve comparison.

The full up beast!:

This is the Right channel with the EXO-45-VS Output Transformer, EXO-04 plate choke with an AVVT 2A3 at 10 kHz, 10 usec/ div, 8.2% distortion (output pot limitation.) (6.8 V rms)

This is the Right channel with the EXO-45-VS Output Transformer, EXO-04 plate choke with an AVVT 2A3 at 1 kHz, 100 usec/ div, 10% distortion. (6.94 V rms)

This is the Right channel with the EXO-45-VS Output Transformer, EXO-04 plate choke with an AVVT 2A3 at 100 Hz, 1 msec/ div, 10% distortion. (6.79 V rms)

This is the Right channel with the EXO-45-VS Output Transformer, EXO-04 plate choke with an AVVT 2A3 at 50 Hz, 2 msec/ div, 7.4% distortion. (6.55 V rms) The clipping on the top waveform is from running out of stored current in the choke. I'll need higher bias current to improve this. The clipping at the bottom of the waveform is from running out of voltage across the output tube. I'll need a higher B+ to help this problem out. Higher current + higher B+ = more power loss in the tube. The 2A3 is already being run at maximum rated power.

This is the Right channel with the EXO-45-VS Output Transformer, EXO-04 plate choke with an AVVT 2A3 at 20 Hz, 5 msec/ div, 10% distortion. (5.60 V rms) Notice how the voltage collapses at the zero crossing. This is usually indicative of running out of output iron. But hey, I'm getting 3.7W out of a 2W piece of iron.

Chart 7: Right channel, EXO-45-VS Output Transformer, EXO-04 plate choke, AVVT 2A3:
Distortion vs Output Voltage into 8.45 ohms on 8 ohm tap with AVVT 2A3 output tube. (Left Amplifier)
Note: 6.55 mV hum + noise on top of a 1.0V output adds 0.655 % distortion + noise with zero distortion.

A while ago I posted a comparison on the Bottlehead BBS of the EXO-45-VS with 10H choke on the plate vs. the stock Paramour output transformer with a 50H (real) plate choke. The 50H with stock output transformer had more bass than the 10H/ EXO-45-VS amp, but the bass (mids and highs) from the 10H/ EXO-45-VS were cleaner. Choosing between the two amps could cause a few "passionate dialogs (1)" between friends.

 (1) "passionate dialogs = arguments for those who use the old fashion political speak ;-) .

The newest 50H/ EXO-45-VS transformer installation is not fully broken in. Below is what I notice when comparing the 50H (real) plate choke with an EXO-45-VS output transformer (still breaking in)  to a 10 H choke on the plate with an EXO-45-VS output transformer (broken in). This comparison was done by just shutting one channel off at a time. I'll do a single speaker - single channel source comparison later.

50H choke = good bass, not boom car bass, bass that is effortless. Each note is more distinctly a different pitch.  The 10H choke just does not go as low in frequency or have the authority that the 50H choke provides.

50H choke = the midrange also does not change when bass notes play. I didn't notice this before, but I do now. It is subtle change, but noticeable.

50H choke = Resolution and focus. I can hear studio reverb on vocals as separate and sometimes bit horrid sounds in some cases. The main vocal is clean, the reverb is metallic with a hollow sound. The sound of the piano keyboard action is very audible with the 50H, the 10H masks these nuances.

10H choke = A bit more snap on wood hitting wood sounds. This may be because there is less bass information making the high frequencies sound relatively hotter.

10H choke = A little less horn sound from the "Horn" speakers.
1. This may because the 50H choke is presenting more detail so this sound is more noticeable.
2. This may be because the output impedance of the 50H choke/ EXO-45-VS is a little lower in the midrange. This lower impedance will boost the midrange.
3. This "horn sound" was a bit more annoying with zero break-in time, it is getting better with break-in time. It may go away completely with even more usage.
4. This also could be the change in harmonic spectrum that MQracing (Mikey) is talking about.
5. It could be now I can hear a peak in the Fostex drivers in my speakers that was masked before.
6. It could be the recordings.
7. It could be the rising input impedance of the Fostex FE108 Sigma at high frequencies causing HF boost because of the low damping factor of the amp. (This is a new observation not on BBS post.)

Even with this nit picking about the "horn sound", the full iron upgrade is clearly the better unit. The only "passionate dialog" that could occur is "Rats! I don't have $300!" for the all the new iron.

I want to recheck the 10% distortion output power levels with the 10H choke and then install the 50H choke into the other channel. The channel imbalance in the image is noticeable.

The 50H/ EXO-45-VS combination is a winner. I hope I get a chance to compare it to a Paraglow. I still wish that in  Sept. (at the show) for someone to have a good 5K and a good 2.5K transformer running off a 2A3 so we can compare the two.

I like the sound with the more expensive iron. I've got more expensive amps sitting around collecting dust at the moment so the money alone ain't making it sound better. I'll put my wallet with $73 in it on top of the amp [all the cash my wife and I have for the weekend] just to verify that money alone doesn't improve the sound ;-).

Doing both upgrades together is what I recommend. I wish I could compare what I've got to RBP's double output iron Paramour. A BCP-15 with double iron may be a way to slash cost. I have a sneaky suspicion that the resolution improvement from the EXO-45-VS won't be there with the double the stock iron. I suspect a good portion of the bass improvement will be there with the double iron. However, the old adage about "silk purses and "cow's ears" is true more often than not.

Note:  If you do RBP's double iron mod, I'd check the orientation of the iron to make sure the coupling to the 115V power transformer is minimized.

With the increased resolution I'm getting, I'm going to have to go through and re-tweek my system to see what other improvements are lurking behind untried mods. (Yes, I'll post what I find.)

I really like what is happening. I've got bass now I didn't know I was missing.
I have excellent detail and imaging. The extent of the improvements were masked when one amp had a 10 H plate choke and the other had an EXO-04 plate choke.

I still have the harshness I don't like; HOWEVER, I am beginning to believe more than half the harshness is in the recording and was masked before. Some recordings have no harshness. Some are horrid. I am listening to an artist that every third track is not harsh, go figure.

Note: (1/14/02) I've found the harshess. It was a combination of a slight HF peak in the speaker,  the 2A3's grid being driven too hard and not having the Paramour cathode mod.