I posted this on another forum as well hoping to get some information in time for my project due date. I am not sure if this is the right place to ask this but I am hoping that if its not you guys can lead me in the right direction at least. I am working on a project and i was wondering what are the amps that hammond transformers work in as drop in replacements or upgrades with little or no mods...Thank you very much anticipated.
peace&love
peace&love
I'm no tube expert at design level, but as Junkie says, the design of the amp dictates what kind of transformer to use. Hammond makes transformers to suit most of the common classic combinations of PP output tubes, like EL34s, KT66s, 77s and 88s, 6550s, EL84s etc. etc. Pinpointing specific amps is a major task and will make a very long list! Forget about McIntosh, though, - most of them use special transformers.
I buy Hammond PTs and Chokes almost exclusively for my amplifiers. Are the best? Maybe not, but if one of them ever goes south, a replacement is just a click away.
I've used various output iron (Audio Note, One Electron, Electraprint) and haven't used any of Hammond's iron until now. I'm using the 1627SEA in my latest amplifier project - so far I've been very pleased for the money.
I've used various output iron (Audio Note, One Electron, Electraprint) and haven't used any of Hammond's iron until now. I'm using the 1627SEA in my latest amplifier project - so far I've been very pleased for the money.
ipop07 said:
I designed a project based on PP 807s, and used a Hammond 1650H. This is rated at 30W, 6K6ct (PRI), 4-8-16 (SEC). It promised f(l)= 20Hz and f(h)= 30KHz, and that's what I measured open loop. Sure, may not the the "best", but then, again, Hammonds don't cost what Lundahl, Magnequest, &c cost. I got somewhat better performance from a NOS Stancore OPT, but that one was a 4K4ct primary, so not really a fair comparison.
The straight PP OPTs (no ultralinear taps) work just great. Can't vouch for other Hammond xfmrs, and I have heard that they have been having difficulties with their SE OPTs (wonkey frequency behaviours) and UL OPTs (miswired primaries).
Take your pick: YMMV.
ipop07 said:
Tell us more about your project, and maybe we can better answer your question. You ask which amps will accept a Hammond transformer, but you have no specific amp or Hammond transformer in mind. This is a diy forum - I'd expect that there are lots of "Hammond compatible" amplifiers built by the forum members. I've got a 6L6/EL34/KT88 single ended amp with a Hammond power transformer, and I've also built a push-pull EL84 amp with Hammond outputs. Would they count? The Hammonds weren't really "drop in replacements" - the Hammonds were the original transformers the amps had from the day they were built.
wg_ski said:
hey-Hey!!!,
Depends on what power you want. Class A, or close to it would want ~360V and 110 mA idle per tube( slightly less if you rig it U-L ). More power means more B+ and less idle current. Where you feel like drawing the line is quite open to discussion I think.
cheers,
Douglas
What kind of power? Why, the most I can realistically expect to get, of course. I have several matched quads, so I'm not opposed to the idea of paralleling to make the best use of those OPTs. At 5k P-P, that's not exactly the easiest way to get 75 or more watts - the plate voltages will have to be high and currents low. I'm not sure just how high I can push it. My prior experience with tube amps stops somewhere around 350V, but that's with EL34's. As for plate supply, I have a number of 600-900 VA toroids that I can put a secondary on.
wg_ski said:
So this is a max-power effort. Not my idea of fun. 30W of Class A is about it. I don't see the benefit to all the cuts I'd have to make in order to double the power. I'd rather go for a moderate amount of excelelnt over more of the same sort of amp that delivered the stellar reputation the max-power, comercial, AB U-L amps delivered to PP. No thanks...
cheers,
Douglas
I am curious about thoughts anyone might have on one I am building soon. I am planning to use a Hammond 1627SEA rated at 30W, 2500 ohms, 160ma in a single ended amp using the 40% taps with either a large bottle 6CA7 or an EL34 cathode biased. This is a guitar amp I am talking about with my own breed of front end design, probably a JTM45 style PT, a 5AR4 or 5U4 rectifier tube, star grounded design, with DC filaments, small box style head design. Should be curious, loud, but friendly... ~Philly
I very like OT Hammond....I use only this brand, 125FSE-90 ma for my 300B and 2A3 RCA/they keep 20-30000 with the same form and same amplitude/ and sound is amazing, clear, very pleasant ...., 1608 for PP 6005GE /really 30-30000Hz/,... 125E for PP 6P1P, 1650 for PP 6P3S-E/20-30000/. I used in my project SE 6V6Silvania & 12AT7Silvania only transformers OT, PT, chokes and enclosure from Hammond. https://picasaweb.google.com/azazello52/Amplifiers#5539473862692374338
I can tell you that it won't sound like a normal guitar amp. It will also be rather heavy. The 1627SEA is large and weighs over 10 pounds. You will not get any transformer distortion unless you operate the output tube in the meltdown region, and maybe not even then. I built a guitar amp using a 1628SE and I didn't like it. The amp was just too clean.
Much of the "sound" of a guitar amp is due to an under sized OPT. This one is oversized for any guitar application within its power ratings. If you want a clean amp for an acoustic guitar or keyboard then use it, otherwise I would go for one of the 125 series.
I came across an old set of 1650H, no UL taps in beat up red and white cardstock boxes, probably from the 60's. The PO had restacked the EI plates to try to make a SE transformer with a paper gap, I was afraid that I would not be able to restack it and return it to its original condition. It took most of an afternoon to unstack, flatten and restack it. I have new found appreciation for transformers.
I've tried them against a set of modern 1650H and 1650P's with 2 amps in triode mode, a ST70 style clone SV6550-C-'s and sweep tube amp with 6LB6's. With both amps, the older iron won, don't misunderstand the current 1650H + 1650P's are a very good transformers in both UL and triode mode, I prefer triode mode...... Does anyone know what the differences are in the construction, plate thickness, wire used etc???
I've tried them against a set of modern 1650H and 1650P's with 2 amps in triode mode, a ST70 style clone SV6550-C-'s and sweep tube amp with 6LB6's. With both amps, the older iron won, don't misunderstand the current 1650H + 1650P's are a very good transformers in both UL and triode mode, I prefer triode mode...... Does anyone know what the differences are in the construction, plate thickness, wire used etc???
Have a Hammond 1627SE (thats the old version, the 1627SEA is the new one) in daily use in my EL38 SE (UL-mode). Primary inductance is gigantic and so is the low frequency response. On the other hand, leakage inductance and capacity is rather high, but since I use feedback this isn't a big problem. This Hammond iron is really great.
I think what everyone is assuming you know is that hammond treansformers are primarily sold to DIYer who are building their own amps from scratch, not necissarily as an OEM replacement. However Hammond makes a very large variety of Trannies so they probably have one to fit most projects. It's like asking what cars champion spark plugs are made for.
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