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Vintage threads from the first ten years

Questions for Speedracer.

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10/2/2000 8:45 AM
Mark Abbott	Questions for Speedracer. Dear Joe Could you give me Steven Delph's web address or email address. I wish to get him to wind a class"A" transformer for me. Also I've seen quite a few posts about JTM 45 amps, and I thought you said in a reply that the output transformer of these amps has a 8K primary impedience, is this true? Yours Sincerely Mark Abbott.

10/3/2000 3:03 AM

Hi Mark:

Stephen's address is:
flying.kiwi@paradise.net.nz

If I may, I would add that he does beautiful work.. He's really a craftsperson in the classic sense.

Also I've seen quite a few posts about JTM 45 amps, and I thought you said in a reply that the output transformer of these amps has a 8K primary impedience, is this true?

To the best of my knowledge, yes it is. I have a couple original OT's (RS Spares Deluxe) and have read up on newgroups etc.. the consensus seems to be 8K, and at first I was sceptical. But running listening tests at 6.6k as well as 8k there is no mistaking the correct primary load IMHO. 6.6k is nice, but a little buzzy and not quite right. 8k is just flat out unreal.. Also, the older of the 100W OT's we RI'd was 4K, which would be fatally high with EL34's (esp at >500Vg2!) .. it may be circumstantial evidence, but it makes sense to go with half of your 50W load.. The final answer is that I have not peeked under the hood of a real JTM45 to see. My $5 is on 8K though.

HTH,

Joe Pampel

10/4/2000 12:20 AM
Ian Anderson	Joe/Speed, Any news on a JTM45/Bluesbreaker OT becomming available soon? ... Ian

10/4/2000 4:46 PM

Hi Ian:

the JTM45 is coming along, but slowly. We have built and tested some prototypes but it's not where we want it yet. Having spent a lot of time with a real RS tranny, I guess I'm spoiled..

It's not always easy to get the same tonal & dynamic responses with modern materials, but we will. When ours is as good as the real one, I'll be happy and we'll start cranking them out. I am hoping to have them all tweaked up by year end.

10/4/2000 6:35 PM
Ian Anderson	Nice one Joe, I'll look forward to it. Email me when they're ready. ... Ian

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