Dennis Had Inspire Amps

[FloridaBoy]

[quote=pstrisik;732057]

Originally Posted by FloridaBoy

Correct. Mine is a 1969 "7 notch". Too bright for me.

So FB, what do you think are the desirable variants of the Mullard GZ34, besides the metal base kind that cost a fortune?

Peter, in these amps I'm not sure. I have 2, a metal base and a double D getter Bugle Boy and they sound the same...because they are identical internally one just has the metal base. No kidding, just a little known fact. I also have a Westinghouse, not sure who made it and it is quite good. I will try a Gold Lion or reissue Mullard and post after the new one settles in.

[FloridaBoy]

Steve, the best thing to do is Google a tube you are interested in and also search the Tubes Asylum on Audio Asylum. This will give you a pretty good idea if a given tube will work for you. It's not exact science but better than simply rolling the dice.

Regarding speakers, after 30 years the caps dry out and replacing them never hurts.

[SteveSem]

Thanks Florida Boy, I appreciate the guidance.

Edit -- Apparently, it was the tube. I had purchased a 274B and saw that it can typically be used in place of a GZ34. I plugged it in normally with no special pushing or twisting, and it powered up just fine. I guess the JJ GZ34 is bad. Maybe a bent pin or something?

I am having a problem with my non-Had preamp, and I'm hopeful that some of you guys with lots of tube rolling experience may recognize it.

The rectifier tube in my preamp does not seem to sit correctly. It will work if I press and twist until it sits just right. But the next time I turn on the amp, the rectifier will not power up until I again fiddle with it again. The two smaller tubes are fine.

Any ideas on simple fixes?

[pstrisik]

edit: oops, too late!

Steve,

Just the obvious..... try a different rectifier first. If no problem, likely the tube. If same problem good chance it's the socket. I had a socket do something similar with my LP-2 a while back. Dennis swapped out the socket and all was good again. It was one of those little metal retainer collars inside one of the pin holes that came loose. I now use socket savers to avoid the problem. I think the risk of socket problems gets greater the more your swap tubes.

If it isn't the tube, you could use a flash light and an unfolded paper clip (amp off of course) to gently probe those retainers in the pin holes to see if one seems to be loose. Also check inside the unit and check the soldering at the bottom of the socket. If you have a multimeter, you can test more conclusively for poor connections.

Beyond that, I wouldn't know.

[pstrisik]

Originally Posted by Simonatsea

I have the Gold Lion GZ34, I thought from the reviews it would impress however it was a little harsh/grainy for my tastes. I found my holland made 5Y3 had just as much power and drive but also was a lot more refined.
Again, my top tube is the USAF 596. Beats my EML 5u4 mesh and destroys the Sophia 274b. I just wish I had Two of them so I wouldn't have to decide between putting it in the LP2 or the 6V6 amp. I paid less than $70 on the bay. They do pop up from time to time.

596, Tube 596; Röhre 596 ID33408, Full-Wave Vacuum Rectifier

It seems this rectifier is rated at 3 amps. Most of the rectifiers we have been using are 2 amps or less. Is this tube ok in the SEP Inspires?

Edit: Well, I see that the 5U4 is 3 amps also, so there's one that has frequently been used.

[BearCityUSA]

Anyone try a ting sol 26E6WG? A 6L6 variant with an octal base. Listed on a bulk sale on that auction site at the moment.

[SteveSem]

This thread has become a massive collection of information about the Had Inspire amps. I've been putting together some notes for my own use in getting the best out of my 6L6 amp, and I thought others might enjoy having the overall wisdom of the thread posted in one place. So, to start with the 6V6 - apx 5 watt configurations here are tubes that were either recommended by contributors throughout the thread or supplied by Dennis with particular amps. Please feel free to add to this.
Sovtek 5Y3 (from Dennis)
RCA black plate 5Y3GT
EML mesh plate 5U4
Sylvania 5Y3G
Rodgers 5Y3 (Holland)

Pope 6V6
Visseaux 6V6
RCA 6V6GT/VT-107A
Genelex 6V6
Hytron 6V6
Gold Lion Reissue(from Dennis)

Telefunken E88CC
RCAsn7
Full Music 6SL7
Voskhod “Rocket”
Zytron labelled Tung-Sol 6SL7
NOS ZENITH 6BX7GT (from Dennis)
BRIMAR 6SN7 (from Dennis)
BRIMAR 6SL7 (from Dennis)

[FloridaBoy]

Originally Posted by SteveSem

Thanks Florida Boy, I appreciate the guidance.

Edit -- Apparently, it was the tube. I had purchased a 274B and saw that it can typically be used in place of a GZ34. I plugged it in normally with no special pushing or twisting, and it powered up just fine. I guess the JJ GZ34 is bad. Maybe a bent pin or something?

I am having a problem with my non-Had preamp, and I'm hopeful that some of you guys with lots of tube rolling experience may recognize it.

The rectifier tube in my preamp does not seem to sit correctly. It will work if I press and twist until it sits just right. But the next time I turn on the amp, the rectifier will not power up until I again fiddle with it again. The two smaller tubes are fine.

Any ideas on simple fixes?

I think there is a problem with the socket. It could be loose..as in not secured to the chassis or there may be a an issue with the wiring. BTW, the JJ GZ34 can be problematic and I would replace it. The Sovtek 5AR4 is a better, more durable choice and it is not expensive. Are you using the JJ in the preamp?

[SteveSem]

Originally Posted by FloridaBoy

I think there is a problem with the socket. It could be loose..as in not secured to the chassis or there may be a an issue with the wiring. BTW, the JJ GZ34 can be problematic and I would replace it. The Sovtek 5AR4 is a better, more durable choice and it is not expensive. Are you using the JJ in the preamp?

Yes, it did turn out to be the tube, and it was in the pre-amp. The pre-amp came to me with JJ tubes. The only spare rectifier that I had was a Sophia 274B, which I was planning to try in the Inspire. But when this happened, I tired it the pre-amp and it worked fine, though my sense was that it placed a lot of emphasis on imperfections in the source. For example, records that weren't perfect and an FM jazz station that has a moderately weak signal. It sounded much better on perfect records than the JJ had. I have no digital sources for this system yet.

I am looking for other rectifier alternatives and have an older used Mullard 5a4 on order. I'd like to try a 5Y3 as well. Do you recommend the Sovtek as an alternative to the Mullard?

[x3workshop]

Originally Posted by FloridaBoy

Steve, the best thing to do is Google a tube you are interested in and also search the Tubes Asylum on Audio Asylum. This will give you a pretty good idea if a given tube will work for you. It's not exact science but better than simply rolling the dice.

I'd respectfully disagree and say that it isn't any better than rolling the dice unless it is used in the same amp. Since Dennis's designs are continuously evolving even the differences within the same 'model's transformers (PT&OPT) are significant enough to question the usefulness of these comparisons. Everyone's systems are different and tube choice/preference is subject to many, many factors.

I've always found it best to sit with a specific tube for a prolonged period of time before making a final judgement.

Also, regarding rectifiers, (or *any* tube) two tubes of the same brand/design can differ greatly between samples so a seven notch that sounds legitemately bad in your amp could sound wonderful in another or you might like a different seven notch sample.