Any Experiences with Gennlab Test Tapes? Need Guidance from Seasoned Techs

ThomOfYorke

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#1
Hi all,

I'm looking to buy the test tapes I need for my decks, and Gennlab has been a name I've seen mentioned a lot in these discussions. From what I've gathered, there's only three worthy sources for new test tapes these days: A.N.T., Gennlab, and Hanspeter Roth (HPR). I already have HPR's tapes, but I wanted to get some more accurate ones. From ANT's website, it looks like tape production is on hiatus for a while, so that leaves Gennlab. But as a beginner, I find his website a bit difficult to parse. I've gleaned that I need his Nak equivalent tapes, but when I asked on another forum, I got advice about which tapes to get that seems to conflict with what Gennlab said about his tapes, leaving me unclear as to what to get. While I trust the advice I got from the other tech (in fact, they're the person whose advice I followed in accumulating all separate, analog bench components), it was stated in a way that I didn't fully understand and when I asked for clarification, the receiving party apparently took offense, took me to be suggesting that they don't know what they're talking about, and told me I was on my own from now on.

From what I've been told, the PB FR tapes need to be exactly 20dB lower than the level tape, and that the level tape needs to be 200 wBn/m ANSI. Gennlab has such a level tape, but the website states that it is 'not suitable for Nakamichi decks' and his Nakamichi equivalent level tape doesn't have specified reference fluxivity stated. So the tech on the other forum recommended to just get the 200 wBn/m one and ignore the claim that it isn't suitable. But then he said that since this is the case, I'd need to get different PB FR tapes than the Gennlab Nak equivalents, since the ref. flux of those is not stated either, and so to ask whether there is any tape that "can be used to make a chart of Play FR with 70 uses EQ. For example a tape that has 400hz, 5k, 10k, and 15k tones on it. All recorded at the same level like -20db." Gennlab doesn't offer such a tape. So I asked whether I should get different tapes elsewhere if I couldn't get any of the PB FR tapes from Gennlab, at which point the tech helping me threw his hands up and said I was on my own. I understand it's frustrating helping someone new to something, especially online where communication is more difficult, but I assume that I am failing to understand something very basic in what was told to me such that this person took me to be insulting him by asking further questions rather than simply being confused.

Basically my question was, if I can't get the PB FR tapes from Gennlab, then where should I get them? And as a beginner, I was unsure why the 200 wBn/m level tape was stated to be unsuitable for Naks by one guy who knows what he's talking about, and stated to be the tape I need by another guy who knows what he's talking about. (I think this is what provoked the latter person, but it's an honest question.)

So at this point, I just want to hear from any techs who've used Gennlab tapes with good results, especially with Nakamichi decks. In particular, could someone confirm that I should get the 200 wBn/m level tape and possibly recommend other sources for PB FR tapes, or at least tell me which models of FR tape would work so I can look out for them on eBay? Or if the Gennlab Nak-equivalent tapes are indeed good, could someone maybe help me understand the disagreement mentioned above? I'm out of my depth.

Thanks all.
 
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#2
Just get the HPR tapes for €60 off ebay Thom. They're all you need, seriously. I feel like you're chasing your tail and looking for things you don't absolutely need. I'd place your focus on actually getting down to practicing refurbing decks at this stage. Use the tools you already managed to get and get cracking. You can finesse the toolbox requirements later.
;)
 
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#3
@ThomOfYorke did you update your TH thread?
I just posted asking for advice on buying a (real) Nak T100.

Anyone here have any tips on purchasing one? What to look out for etc?
I'm assuming that taking a known calibrated deck and some cal tapes and cross-referencing might be a good idea. Seller has a scope so I might also be able to hook it up and do some checking too.
 

ThomOfYorke

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#4
I posted on my TH thread asking for advice on the Gennlab test tapes the day before yesterday and yesterday. But after the above misunderstanding, it hasn't gotten any further replies.

I managed to score an original ABEX THG-801 gauge which is out for delivery today, so when it arrives I might update the thread again.
 

ThomOfYorke

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#5
Just get the HPR tapes for €60 off ebay Thom. They're all you need, seriously. I feel like you're chasing your tail and looking for things you don't absolutely need. I'd place your focus on actually getting down to practicing refurbing decks at this stage. Use the tools you already managed to get and get cracking. You can finesse the toolbox requirements later.
;)
I'm sort of just researching and accumulating the gear I need right now since I haven't had any extended periods of time to actually work on anything. I'm currently working on my dissertation so I'm just trying to get the necessary tools I'll need once I eventually get time to work on a deck. I tend to get obsessive about things and right now I have to dedicate most of my time to writing. But since a lot of this equipment requires searching and waiting, I figure it's worth doing in the short moments I have now.
 

nakdoc

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#6
As long as your goal is semi-pro level repairs, any of the 3 "test tape" producers are fine. Typically they record tapes on a dragon, but a better choice is a deck with manual record head azimuth so you can compensate for cassette shel differences. There are 3 tapes you need (or one tape with these 3 recorded; Dolby operating level aka 0Vu/0dB at 400 Hz., 15kZ recorded at -20dB, and 3kHz recorded at -5dB or 0dB or whatever. PB frequency response is a waste of time. A 10kHz azimuth tape isn't good enough for decks that can do 20kHz. I would choose from the 3 tapes the one with longest 15kHz time you can get. 10 minutes of azimuth test one isn't quite enough. Also note that none of the 3 tapes are full width mono, so head and guide height have to be correct or you'll be trying to fix tape path issues by turning electronic pots.
 

George S.

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#8
As am I.
I'm currently rebuilding a Phase Linear 7000 Series 2 deck and the specified test tapes the service manual calls for have different specs than the Hanspeter Roth tapes I have.
So, I found this thread and printed it out. Good info about test tapes beginning around post #9.
Using the HPR tapes should be a non issue.
I'll have this on the bench along with the service manual when I begin alignment.
https://www.tapeheads.net/threads/pioneer-ct-a1-phase-linear-7000-saga.83726/
 

J!m

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#12
The Tascam 0dB meter indication is 250 nwb/n. Dolby level is at -3 (from my memory) which I have confirmed with a Teac dolby level test tape I happen to have.
 

ThomOfYorke

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#13
Thanks, George. The more I've trawled the forums for clarification on the Dolby level/Nakamichi question, the deeper the rabbit hole becomes. Renowned techs are arguing about stuff I don't understand, citing white papers making theoretical claims I don't have the background to verify. It gets confusing when you know less about a particular issue than both parties debating that issue! Deference to experts is the reasonable default in such scenarios, but when the experts disagree, it's a difficult spot to be in.

SO, I finally just decided to order the suite of Gennlab Nak-equivalents (among which there's a 15kHz azimuth tape and a 3kHz speed/W&F tape), plus a standard 400hz, 200nWb/m 0Vu/0dB Dolby level tape as well, so that way I'm covered on either side. If it turns out I spent more than I needed to, whatever, I just don't want to go through the hassle of ordering internationally, and paying international shipping, then still not having the right tapes. Though I do gather that as long as you know the ratios/conversions for the tapes you're using, you can get by in some (most?) cases. But since I don't know that stuff yet, figured I'd go the simpler route and get the Nak-equivalents so I can just follow the SM if needs be.

I'm going to use the HPR tapes on entry-level decks until I improve and learn more, since they were only $60 for the set, but I wanted to get some nicer tapes from Gennlab now since who knows when these guys making good tapes are going to stop, or go on hiatus, or have something happen that prevents them from making them available. (That's what happened when I was looking to get an alignment gauge: I figured, hey, Willy Hermann is producing copies, I can get one of those any time. Then sure enough, right when I finished accumulating the relatively rare bench gear, and was ready to purchase a gauge, WH stopped producing and selling the WHS-300 gauge. So I had to scan eBay everyday until I luckily found an original ABEX THG-801 and snapped it up in a millisecond. Don't want to make the same mistake in sourcing these tapes.)
 
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George S.

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#14
Thom, I hear you.
I suspect that if one has decent experience with the test equipment, then aligning a deck really isn't that hard.
 

vince666

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#15
The Tascam 0dB meter indication is 250 nwb/n. Dolby level is at -3 (from my memory) which I have confirmed with a Teac dolby level test tape I happen to have.
if 0dB is 250 nwb/m (aka 0dB DIN) then dolby level is at about -1.2dB

and if 0dB is 160 nwb/m (aka 0dB VU) then dolby level is at about +2.8dB

last, there are meters where the 0dB is just the dolby level (i.e. Nakamichi decks and a few others)

....

of course, the difference between the 0dB 160 nwb/m (aka 0dB VU) and the 250 nwb/m (aka 0dB DIN) is about 4dB

there was an useful plot I had made several years ago and shared elsewhere... but I can share it here too, because looking at it helps keeping levels on the various different scales in mind.

here it is:

meter-levels.jpg
 
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