Dennis Had Inspire Amps

[Analog Addict]

Originally Posted by BlackBess

If Mr. Had is calling the slammer a fabulous sounding amp, it must be a winner. If it was reconfigured to incorporate a volume pot, would it need a pre-amp to get that fabulous sound cooking correctly? BTW digging the pic AA posted on Flickr of the KT-88 sep with Groove tubes labeled A-7. A while back I was rooting through old guitar amp gear & saw some spare tubes I had stashed away. Among these were some 6L6 Groove tubes marked H-2 that I had purchased back in ‘79 or ‘80. I thought why not see what my old R&R back-up tubes sounded like in a SEP stereo rig. At first they seemed OK but a little harsh on female vocals & removed them thinking gosh darned guitar amp tubes. After listening to other tubes (& amps) I rolled them back in to give them a proper break-in. While they’re no WE300B’s, they sound surprisingly sweet after some real burn-in. But I would really like to hear the slammer sing with her Vagas PS. When is Hadfest? J/K

Heh, you joke, but I have been trying to twist Dennis' arm to see if we could figure out a way to be able to exhibit at the Capital Audiofest. So far he seems uninterested in the idea. Too bad, because I think we could blow the place away with a complete Inspire system or two including speakers. But Dennis doesn't really want to be a whole lot busier either. I can completely understand. This was supposed to be a retirement hobby for him, but he loves building amps that make people happy, and he can't say no when a whole herd of Bennys are talking....

As far as the groove tube thing, those are actually GE 6550s, a gift of mine to Dennis some years ago. I would personally recommend them if you can find them, but they have to be the GE versions....

[C10]

Hi All, I am about to take possession of an Inspire Fire Bottle 45/2a3 SET amp. It was built 8/22/2019. Curious if anyone has the bias settings requirements and procedures for the 45 and the 2a3 tubes. Know that it takes a 6SL7GT input tube. Do any other work? Any additional information much appreciated too. Looking forward to hearing it! Thanks in advance!

[Isaacc7]

Originally Posted by C10

Hi All, I am about to take possession of an Inspire Fire Bottle 45/2a3 SET amp. It was built 8/22/2019. Curious if anyone has the bias settings requirements and procedures for the 45 and the 2a3 tubes. Know that it takes a 6SL7GT input tube. Do any other work? Any additional information much appreciated too. Looking forward to hearing it! Thanks in advance!

Congrats! Don’t know about that particular amp but typically the Fire Bottle amps are automatic bias. I assume there is a switch to choose between the two kinds of output tubes. The Fire Bottles can also typically use either 6sn7 or 6sl7. I’m sure Dennis will eventually see your question and have the answer put up for you. Might be a little bit since Analog Addict (the usual poster of Dennis’s thoughts)is on vacation.

[cgn-dt-n]

@C10

I found this on the Internet for the 45/2a3 amplifier from the item description in eBay.

PURE CLASS A TRIODE
2 WATT TO 5 WATT OUTPUT WITH VARIOS OUTPUT TUBES

45 OUTPUT TUBES WITH 80 RECTIFIER
2A3 OUTPUT TUBES WITH 5Z3 RECTIFIER

6SL7/6SN7 INPUT TUBES

AUTO BIAS FOR PLUG AND PLAY TUBE ROLLING

Maybe this will help you

[Analog Addict]

I wish I was on vacay, but instead I'm working this week out of town. However, as I suspected, the amplifier is auto biasing, with the only caveat being use an 80 rectifier with the 45 tubes and a 5Z3 with the 2A3s.

And any of the 6Sl7/6SN7/6BX7 tubes can be used on the front end. You'll have to experiment to see what sounds the best to you...

[C10]

Originally Posted by Analog Addict

I wish I was on vacay, but instead I'm working this week out of town. However, as I suspected, the amplifier is auto biasing, with the only caveat being use an 80 rectifier with the 45 tubes and a 5Z3 with the 2A3s.

And any of the 6Sl7/6SN7/6BX7 tubes can be used on the front end. You'll have to experiment to see what sounds the best to you...

Thanks for all the responses so far! Interesting. The person I traded the amp from seems to believe there is some biasing involved. Also in terms of tubes info that I believe they got from Dennis there is no mention of the input tubes but does show combinations of 45 with 5z3 and 2a3 with 83. Here some pictures. I think the bias post they is referring to are those "screws" between the OPT and power tubes. I guess I will know more once the amp arrives. Here some pictures in the meantime.

[cgn-dt-n]

The 83V is a 4 pin version of the 5V4G octal and should not be confused with the HG 83 mercury vapor rectifier.

The screws are more like hum Control pot

[C10]

Originally Posted by cgn-dt-n

The 83V is a 4 pin version of the 5V4G octal and should not be confused with the HG 83 mercury vapor rectifier.

The screws are more like hum Control pot

Helpful! Thank you!

[C10]

Originally Posted by cgn-dt-n

@C10

I found this on the Internet for the 45/2a3 amplifier from the item description in eBay.

Can you link me to this? Searched high and low and can't seem to find it. Thanks in advance!

[rich66]

I have the same amp, has anyone try the 83V rectifier tube for more power?