Tube Amp Archive

Thanks all for your comments.
As I said, I will try to get something better out of this.
Unfortunately, secondary power transformer voltage is pretty low, B+ is 375V only.
I need to check output transformer primary impedance to see if it is worth spending time...
Both transformers are MM made.

JTM45 style? I can't tell what all is going on at the input end of the front panel... No, this amp should be something between plexi and Soldano. Information I found regarding MV45, probably from Joe Morgan: "The MV45 is my take on the small box 50 watt design. It has more gain than a plexi avail b...

Yes, loop is from Tube Town and it is very good solution, as are other their KITs. I upgraded a few amps with their KITs, also tube loops, tested and reviewed, very good. Well, amp just doesn't sound good, from blocking distortion to noise, I would not dig into details here. There are a few online r...

Hi, asking for a help, if you wish to step in... Any owners here, of Morgan MV45? Friend asked me to restore whole amp wiring to stock, but schematics is impossible to find. Amp has been modified, FXloop aded, ... Morgan amplification can not help, they said... At least some detailed photos of untou...

Thanks.
Well, for devices as valve amps are, it really is important, I see now.

Good, so heating is still on safe side. "rhinson", what do you think is better- -to build vintage voltage adapter or to give PT to proff. to change number of windings on (decreasing primary I suppose?)? Actually I never checked Mains voltage before... now I see it also move between 216-219V... :x So...

OK, you get 300-0-300 if you put 240V on pri. But, in schematics is, for 240V pri., 280-0-280. If this is a rule then OK. But, with 240V pri. you get 6,65V on heaters...too much? Ratio is not correct in this case, should be probably 6,3V? As maximum. Paulster, with yours 250V pri. you'll get barbequ...

Thanks rhinson! I didn't know that... I was sure that at prim.240V - sec. will show 280x2=560V, as show their schematics. PT is pretty warm at 240V pri. - it wasn't case before, with different one. And one more info for Ceriatone's Ex. - both trannies are fixed in original holes - no changes needed....

As prommised, here is report with Pacific transformers TW Expr.: PT 32310 OT 25525 Mains AC (wall outlet V=220V) - increased with variac: 1. (Measured with standby switch on, no input signal) Mains to pri.: 230V (not high enough) Output on sec.: 567V B+1 378V B+2 364V B+3 290V B+4 273V B+5 259V Heat...

@Paulster Thanks for your data, my target is to get the one from schematics. We'll find a way:-) @geetarpicker Sound from your CD is my bibel :shock: :D Pretty hard homework to come close to your sound -:) Therefore I'll do everything to assure the same basis (B+ and the rest) @M Fowler It's nothing...

Thanks Paulster,

I think I'll try to find a company which will adapt "new Pacific" PT primary to 220V. In the afternoon I'll check B voltages with 240V from wall outlet (UPS).

@Paulster I'll try today to increase 220V to 240V with my UPS. Do you have any report with values for yours? To compare. Aren't those voltages too low? What's your bias set to? @Allynmey Yes, Pacific told me they're identical to K&M and originals: " The parts are identical to originals and all K&M k...

I'd like to see your comments, advice maybe...thanks in advance :) I replaced my old transformers with Pacifics. (Ceriatone Express) Before were voltages low (comparing to schematics), but now are even lower. Standby switch ON, no Input signal: Tubes are JJ, 3x ECC83S, 2x EL34 PT version EU: 240V OT...

If I have my statistics correct then one curiosity between the Heyboers and Pacifics is that in the chosen windings used for an Express they supply different voltages: Heyboer = 300-0-300 Pacific = 280-0-280 Is there any adjustment in the dropping string between these two? thanks, rj My Pacifics ar...

Hey Gargoyle, I had the same problem. Big Thanks to MFowler - I've got codes for Pacific transformers (and other great help too). Yesterday I received both, OT and PT, EU version, 240V (from Pacific) Transformers were made by the same person who did them for Ken, they told me. At the moment my conta...