AudioRoundTable.com - RDF feed
type: channel
description: Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
items: Thank You!
items: Re: Thank You!

Thank You!
type: item
description: Wayne: Thank you for this new Forum! I'll definitely post here and encourage others to do so. Would it be OK for a small, startup tube guitar amp company owner to plug his new product line here? I don't mean that he would spam the readership, but just include a link to his site in a post. I'll also use this opportunity to thank you for your generosity, in general. I certainly appreciate the technical information you share with the readers.
creator: DMW
date: 2004-07-08T18:00:11-00:00

Re: Thank You!
type: item
description: Personally, I think if it is tastefully done, it shouldn't be a problem. I see links to commercial websites all the time. Of course, the posters are usually the ones who own the website... But, then again, I am not the last word on the subject. :)
creator: Paul Marossy
date: 2004-07-08T18:56:25-00:00

Re: Thank You!
type: item
description: Nobody wants to see the place become too strict, but then again, nobody wants it to be a free-for-all either. Here are the rules: Posting Rules
creator: Wayne Parham
date: 2004-07-08T19:38:17-00:00

Re: Thank You!
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description: I'd just like to say thanks for inviting me to post here. I hope to see some interesting posts in the future. :) Brian Marstran.com </ul(.*)
creator: Brian Wallace
date: 2004-07-08T22:28:29-00:00

Re: Thank You!
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description: I'm glad you have visited, and I hope you'll keep coming back. It looks to me like you have the low-down scoop on the iron.
creator: Wayne Parham
date: 2004-07-09T06:00:49-00:00

Re: Thank You!
type: item
description: I know a little bit about iron and Marshall's. ;) I'll check in here from day to day to see what's up. Brian Marstran.com </ul(.*)
creator: Brian Wallace
date: 2004-07-09T23:51:13-00:00

Re: Thank You!
type: item
description: I understand that the transformers on the website you linked are for Marshall amps. But I'm wondering what the difference is between them and the iron used for hi-fi applications? Are there response differences? Perhaps less need for response at frequency extremes? Or are they made "industrial strength" for high current through the windings and things like that?
creator: Wayne Parham
date: 2004-07-11T05:34:12-00:00

Re: Thank You!
type: item
description: Hi again Wayne, Hello Brian & good to see this forum on its feet! Brian seems quite up on the Marshall iron and doesn't mind publishing useful data for those who might need it. I, too, recently saw Brian's site earlier while researching an upcoming amp project. I found a Bell Carillon PA amp pushing two 6CA7's (USA version of EL34) to 75 woppers. Hmmmmm.... Anyway; To answer simply, typical Vintage guitar amp bandwidth is only about 60 Hz to 6kHz. Most vintage amp makers would buy the cheapest output iron that got the job done and High Fidelity was not on the spec sheet. They are generally stronger reluctance cores that naturally add harmonic and intermod distortion. Some would add more secondary windings for more 5-10% more numerical (salesman watts) output at the further expense of highs. Construction varies a lot and some of the flimsiest looking little OPT's will sound the coolest (because they are so nonlinear). Modern era tube designs are becoming more full range. Boutique manufacturers can afford to put higher quality components with the prices they can get. Some (actually do) go for wider bandwidth and more controlled distortion characteristics! Most higher fidelity design goes toward Fenderish clean tones as one would expect. Sometimes the faster impulse response alone while using limited BW speakers is enough to give more bite and growl. Brighter and deeper 12" speakers are becoming popular as they are more buildable and adopted for modern playing styles. Some boutique makers are gravitating to smaller drivers with more high end. Triple and quad 8" driver combo models are appearing. Classic plexi era Marshalls, in fact, initially came with 5881 or 6L6 output tubes before settling on the rightously grainy EL34 powerplant. Clean tubes--just not "chimey" enough it seems. Plexis will play with relatively little preamp and output stage distortion, before onset of clipping, but nobody cares for their "clean" sound-- preferring to run LOUD enough to get OT distor…
creator: martinleewin
date: 2004-07-20T03:11:15-00:00

Re: Thank You!
type: item
description: Interesting and informative reply, thanks. So if I understand you, it appears that one of the biggest differences between guitar amps and hifi amps is the transformers used.
creator: Wayne Parham
date: 2004-07-20T16:37:28-00:00

Re: Thank You!
type: item
description: That and equalization. Guitar amp bass, middle and treble eq center frequencies are much different and with less loss. There is often simple low pass filtering added to prevent oscillation. Plate resistor HF bypass caps and caps across the transformer primary are very un hifi like. Martin W.
creator: martinleewin
date: 2004-07-20T18:32:42-00:00

Re: Thank You!
type: item
description: Hey Wayne/Martin, Lots of info in your response Martin. The early Marshall RS Spares OT was a cheap Hi-Fi OT made for RS by various companies. It was only rated at 30W though and the JTM45 will push a little more than that. This gives a great saturated sound to the amp when it's cranked. The laminations in this OT were M6 as opposed to the junk steel used later on. The next generation OT's from Drake were rated at the same wattage so the same saturation occurs but they used low grade steel and were interleaved completely different. This effects the tone of the OT and the amp. There was definitely a lean towards less need for response at frequency extremes. This OT was also made with a higher reflected primary Z and this alters the amp sound as well. Hi-Fi amps and OT's are, in my opinion, designed around a wider frequency response than guitar amps and proper loading for optimum power and fidelity. I haven't considered how the newer breed of amps are made as far as a wider frequency range in their OT's. I would imagine that a better speaker setup would be required to take advantage of this as opposed to the standard 2x12 and 4x12 setups. I'm sure I'm just repeating the previous response here but I'd thought I'd answer anyway. Yup, any fool can build an amp. ;) Brian Marstran.com </ul(.*)
creator: Brian Wallace
date: 2004-07-20T20:59:44-00:00