hvyj
3240 posts
Mar 05, 2017
2:12 PM
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Anyone familiar with this amp? It's not the head that is current producrtion. It's the 1x10 combo that was made in the 90s. Ostensibly 15 watts, but nowhere near as loud as a Princeton Reverb, and certainly not loud or powerful enough to play out. I picked one up at a good price to use at home.
Supposed to be class A, but I'm not sure that it actually is. It's tubed like a Fender Pro Junior: 2 12AX7s and 2 EL 34s. But it has a volume and a master volume, three tone controls (treble, midrange and bass) and a boost switch. No reverb, but pretty nice tone. I retubed it with JJs and put a 5751 in v1 and an ECC83MG in V2, and I can get a variety of nice sounding overdriven tones out of it using an Audix D1 snare drum mic with an in line volume control. The Audix D1 seems to be a better match for this amp than my usual 545 Ultimate. Anyway, I'm having fun playing through it at home.
Anyone have any experience with this amp? Is it really class A? Does anyone know anything else about it? Just curious.
Last Edited by hvyj on Mar 05, 2017 2:14 PM
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SuperBee
4563 posts
Mar 05, 2017
9:15 PM
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2 EL84s i think
if it is claiming 15 watts for a pair of el84s, that is gonna be a class AB amp.
i understand they were issued with eminence speakers at first, later production used Blue Marvels. i think the eminence are more highly regarded
seem to be well thought of in terms of audio output but perhaps prone to problems. however, since yours has survived this long maybe that's not really a thing, or maybe its had a sheltered life
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SuperBee
4564 posts
Mar 06, 2017
5:24 PM
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Schematic shows a cathode biased power section which is probably why it's not so loud as a PR.
Has a preamp volume between stage 1 and 2 and the tone stack comes later. There's a master volume after stage 3 and a line out from the preamp.
I read someone said they'd seen a lot with overheating problems so might be worth running a little fan or at least not sitting stuff on it or covering it while it's running.
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hvyj
3242 posts
Mar 06, 2017
6:51 PM
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Thanks. I don't understand how it can have 3 stages if it only has 2 preamp tubes. There is a headphone jack and an ext speaker jack. It does run hot, but my Peavey Delta Blues also runs VERY hot, but from what I understand, it's supposed to.
It's nowhere near as loud as a PR. Not in the same league.
Last Edited by hvyj on Mar 06, 2017 7:50 PM
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SuperBee
4565 posts
Mar 06, 2017
6:59 PM
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Each preamp tube is a twin triode. So 1 tube gives two stages. The 4th stage is used as a phase inverter to drive the power tubes.
The schematic shows the signal tapped off for the headphone from the preamp.
Yes, an amp can run hot and be ok, but the comment I read was specific to overheating-related failure. Only a comment, I have no personal experience with the amp. Have known a few 30s but they are different amps.
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hvyj
3243 posts
Mar 07, 2017
12:57 PM
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Looking at the schematic, I suppose you are able to confirm that this amp is class A/B, not class A?
You don't usually find 3 band EQ on tube amps this small. That's one of the features I like about it.
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SuperBee
4566 posts
Mar 07, 2017
1:31 PM
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If it's 15 watts from 2 el84s (which it is, according to schematic) it's certainly not biased for class A. You won't get 15watts from a pair of EL84 tubes operating in class A.
Had me going for a moment with the OP stating EL34s, which possibly could deliver 15 watts in Class A, but it's clearly an EL84 class AB amp.
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hvyj
3244 posts
Mar 08, 2017
5:29 AM
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Yeah, the power tubes are EL84s. I went brain dead for a minute and made a typo. But the ostensible 15 watts seems very questionable. This amp is only a fraction as loud as my 15 watt Princeton Reverb RI. Fun little amp, though.
Thanks for all the info!
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