Modifications on ASL Hurricane 200 DT ?

Thanks for good tips! I am currently using Electro-Harmonix tubes in all positions, but have been thinking about NOS for the input, as well as tube dampers from Herbie's Audio Lab. I will definitely investigate the caps you recommend!

Hurricanes Forever!

Dimitry, I summarized my thoughts on couplers for the 'Canes here http://www.audioasylum.com/forums/tubediy/messages/94704.html . If you were ready to spend upwards of $5K at Bill's, you definitely can afford the SoniCap Platinums. And...they're $23 each less expensive than the V-Cap TFTFs, = $460 for the 2 amps.

Do you have detailed notes on modifications already performed? If so, if you share them, probably I can give you more to consider. Pls e-mail me at jeffreybehr(at)cox(dot)net. I've ordered the couplers and other parts and am currently co-designing a serious upgrade of the main PS. I'll let you know how that goes with my advisor who has LOTS more experience at this than I.

Where are you? Maybe I can physically help you improve your amps.

I've bought about 4-dozen* 'N7s, NOS and used, and I know they work in the amps, but I've yet to characterize them.

* Just another example of why my wonderful wife calls me Mr. Excess.
.

Wow, you seem very involved in improving your amps. Keep me posted on you endeavors. I am a sometimes tweaker, but some of the things you are contemplating are a bit above my level. However, there is always something to learn from knowledgeable people ! I am in Massachussetts, by the way. If you decide to go commercial, let me know. I am especially interested in you 6SN7 experiments.

On 6SN7s, here's what I wrote to my audio buddies tonite:
"Wow are my ears and brain (?) tired. Just listened carefully to a half-dozen samples of 'N7s in the frontend* of the 'Canes. Of the 6 samples, I made notes on only 4, that is, I think I heard character in only 4 tubes--3 were a little edgy/bright, and one seemed a little warmer. After listening to all 6, several more than once, I replaced the 2 Chinese inverter/driver tubes** with RCAs and left them in; that seemed to increase the spaciousness a bit.

I hope Pat's coming over tomorrow to help!

* 2 Voltage-gain stages in series...cascade, I believe it's called.
** one section of the dual triode is half of the amp's long-tail phase splitter and the other section is the cathode-follower driver."

Listening carefully to stuff like this is WORK for me. Oh well...it must be a labor of love or I wouldn't be doing it.

My 'Cane mods are in 4 general areas--the coupling caps, the decoupling (= frontend) dropping resistors and storage caps (currently 4 'lytics), the main PS, and the grounding wiring and rest of chassis. For the decouplers, I'll be tossing all the 'lytics and replacing them with Solen 'propylenes bypassed with SoniCap-2s. I've ordered them, but I'll soon be determining if the sizes I chose will work. On the PS, I'll be increasing the total capacity a little and putting most (about 80%) in the 1st pole and using only 200µF of Blackgate 500s in the 2nd pole, probably with a little MC-RTX bypass.

I'm going to try to install one piece of 14g. solid copper wire as the ground wire and run it around the chassis instead of having all those little (18g.? 20g.?), stranded wires running all over. I thought about using solid silver but decided that was overkill. I will be using double-20g. solid-silver conductors in teflon airtubes for signal or high-Voltage wiring I feel like replacing. Probably will be replacing few resistors, as resistors generally have far less character than caps, and the resistors ASL uses are plenty good enough for me.

Did you get details on your amps' mods done by Mr. Bogdan?
.

Sounds like you have great plans !

The modifications on my amplifiers were all coupling caps (front and side, so to speak) to MIT RTX and silver wire to from the jacks to the front end. I don't think he did anything else. I replaced the binding posts, some of which had cracked bases (flipping them over, if you are not careful, can put a big bending moment on the posts), with the same kind from the manufacturer. The tops of the transformers have scuffs on them (apparently from several trips to the repair place, where the amps were placed upside down to work on them), which I need to paint.