Dennis Had Inspire Amps

[Musica Amantem]

Originally Posted by x3workshop

Both good irons, a soldering stand is mandatory or you will be burning/melting your work surface and other things nearby!

Thanks, guys. I'll give the Weller a try, as I'm very clumsy and will probably need the station.

[Analog Addict]

Originally Posted by Simonatsea

What is the 3rd picture of? Looks like a preamp of sorts....

Sorry, I'm out of town at a family reunion, so I've not had a chance to check in. The third picture is my personally built 27 preamp that also uses a voltage regulator tube instead of Dennis' solid state approach. Dennis' pre amps also tend to use a cathode follower tube to lower the output impedance, but I didn't find this necessary because for my purposes, it will always be paired with a high impedance tube amp. This was my first preamp build, and despite a few brainfarts and gaffs, it fired up after a quick problem solving session at the shop on Monday before Bearcity arrived, and we had it playing the entire time he was there. Dennis was very complimentary, especially since it hadn't been burned in.

My next project will be a PSE 45 I think, although the temptation to build a 6550 based unit like Dennis' current offering is tempting, I wanted to try something different. Using the IIPS on a true single ended output tube would lose the advantages of the rock solid screen grid voltages, but might be useful in cleaning up other noise and hash that might be present in the signal path. If Dennis likes it, it may, ahem, inspire him to build his own version. However, I work a lot slower than Dennis does, so don't hold your breath...

[Rosco65]

I'm not sure I get the appeal of a PSE 45 amp. Doubling up a 45 tube won't get you more than 4 watts, and I am of the opinion that you can get 4 watts in other ways. Dual plate 2a3's are already pretty much two 45 tubes in parallel. If I were going to do something as unusual as a PSE 45, I might look at something like:

1. SE Type 50.
2. PSE Type 46.

[Musica Amantem]

In my humble opinion, and as an owner of a Decware Minitorii rated at 4 Watts at 8 Ohms and 3.3 watts at 4 Ohms, and having used it with 94 dB's at 4 Ohm speakers for a couple of years, I found the SPL in my setup was enough. The PSE 45 amp at 4 watts is already at a useful power range, and would combine the benefits of the cleaner IIPS and the famous DHT 45 sound. That same power rating in my Tekton Lore 2.0's would produce even higher SPL at 8 Ohms and 98 dB's. So, I for one would be interested. The difficulty here I guess is getting the right special transformers for the more complex PSE topography.

[FloridaBoy]

Originally Posted by Musica Amantem

In my humble opinion, and as an owner of a Decware Minitorii rated at 4 Watts at 8 Ohms and 3.3 watts at 4 Ohms, and having used it with 94 dB's at 4 Ohm speakers for a couple of years, I found the SPL in my setup was enough. The PSE 45 amp at 4 watts is already at a useful power range, and would combine the benefits of the cleaner IIPS and the famous DHT 45 sound. That same power rating in my Tekton Lore 2.0's would produce even higher SPL at 8 Ohms and 98 dB's. So, I for one would be interested. The difficulty here I guess is getting the right special transformers for the more complex PSE topography.

The 45 is a nice tube for acoustic and small scale music. The right 104db speakers would make it more viable as an all rounder. It worked with the 98db
single driver speakers I had but had limitations.

[Rosco65]

Originally Posted by FloridaBoy

The 45 is a nice tube for acoustic and small scale music. The right 104db speakers would make it more viable as an all rounder. It worked with the 98db
single driver speakers I had but had limitations.

I agree that the 45 is a great tube, but my point was a parallelling 45's doesn't make sense to me. Unless Dennis method of paralleling output tubes adds something really special there is little reason to do a 45 PSE. Double plate 2A3's are already two 45's in the same envelope, with twice the power and half the output impedance. Unless you wanted to treat each plate separately I see no advantage. If it is more output power from a true triode you want, there are more interesting ways to do it. The 421a/5998 sounds fantastic and puts our 4wpc. If you wanted to parallel these they are two channels in the same envelope. A Type 50 or AD1 tube would also be cool, but expensive.

At the end of the day, if you wanted a 4-5 watt single ended amp, I would stick with a 2A3, 6V6, or 300B. I would avoid a 421a (even though I own a 421a amp) because tubes are expensive and in demand from the headphone guys. If you wanted to get really fancy with the power supplies you can.

[deafbykhorns]

Who is winding the output transformers for Dennis?

[BearCityUSA]

Originally Posted by deafbykhorns

Who is winding the output transformers for Dennis?

A really good question. I understand from Dennis that it is a fella like him. A retired hobby-ist, maybe from CA, if memory serves. I'll bet Analog Addict or Straitwire may be able to add more.

[Rosco65]

Originally Posted by BearCityUSA

A really good question. I understand from Dennis that it is a fella like him. A retired hobby-ist, maybe from CA, if memory serves. I'll bet Analog Addict or Straitwire may be able to add more.

I was thinking the same thing yesterday. Given the fact that Dennis has been having output transformers made for him for 30 years with Cary and AES, it may be the guy(s).

Top quality output transformers are expensive, which is probably why the PSE costs as much as it does (along with Dennis supplying two sets of quality output tubes!). I'm sure that Dennis gets a "friend price" for his outputs. For reference, the well-price Hasimoto 2.5-3.5k 20W SE output transformer runs $478 per pair. My back of the envelope math says that Dennis' parts cost is at least 50% of his sale price.

[Comzee]

I talked about this 6sn7 in an earlier post, but to recap now that I've had about 50hr of listening using it.

The rca red base 6sn7 is a A+ tube! "red base" doesn't really help in looking for it, because bases can be "red" as a generic statement when searching for tubes.

It's 5 support rods, 3 mica, 2 top D getters.
I took some pictures to hopefully help identify these features if anybody where to look for it.